A review on Bi₂WO₆-based photocatalysts synthesis, modification, and applications in environmental remediation, life medical, and clean energy

Highlights

● Recent progress of bismuth tungstate (Bi₂WO₆) as photocatalyst was summarized.

● The review reported the fabrication and modification of Bi₂WO₆-based materials.

● Bi₂WO₆-based photocatalysts have been widely used in multiple areas.

● Future perspectives on the use of Bi₂WO₆-based photocatalysts were discussed.

Abstract

Photocatalysis has emerged a promising strategy to remedy the current energy and environmental crisis due to its ability to directly convert clean solar energy into chemical energy. Bismuth tungstate (Bi₂WO₆) has been shown to be an excellent visible light response, a well-defined perovskite crystal structure, and an abundance of oxygen atoms (providing efficient channels for photogenerated carrier transfer) due to their suitable band gap, effective electron migration and separation, making them ideal photocatalysts. It has been extensively applied as photocatalyst in aspects including pollutant removal, carbon dioxide reduction, solar hydrogen production, ammonia synthesis by nitrogen photocatalytic reduction, and cancer therapy. In this review, the fabrication and application of Bi₂WO₆ in photocatalysis were comprehensively discussed. The photocatalytic properties of Bi₂WO₆-based materials were significantly enhanced by carbon modification, the construction of heterojunctions, and the atom doping to improve the photogenerated carrier migration rate, the number of surface active sites, and the photoexcitation ability of the composites. In addition, the potential development directions and the existing challenges to improve the photocatalytic performance of Bi₂WO₆-based materials were discussed.

Graphical abstract

Keywords

Bismuth tungstate / Synthesis and modification / Photocatalytic application / Environmental remediation / Clean energy / Medical science

1 Introduction

Currently, human beings are facing a variety of problems including environment pollution, global climate change, and energy consumption. The inexhaustible renewable energy of solar has been widely concerned by numerous researchers. To address the looming problems of environmental pollution and energy shortage, the photocatalysis technology has been recognized as a promising treatment method to convert solar energy into chemical energy (Fehr et al., 2023). By modifying photocatalyst, photocatalysis technology which is a potential technology for green development can effectively enhance solar energy utilization and pollutant removal, which is a potential technology for green development (Mao et al., 2022c; Shi et al., 2023). Photocatalysis technology mainly aims to form electrons and holes in the catalyst under light excitation and produce a series of active substances with high REDOX potential, which may destroy the internal chemical bonds of organic or inorganic pollutants in the environment through REDOX reaction degrade pollutants (Huang et al., 2019; Li et al., 2020a). After decades of research, photocatalysis has achieved significant breakthroughs in some crucial areas including the development and research of catalyst mechanism, removal of organic pollutants, water cracking to produce hydrogen, detoxification of highly toxic inorganic, as well as reduction of carbon dioxide (CO₂) into fuel (Liu et al., 2022; 2023; Monticelli et al., 2023). In the development and application of semiconductor photocatalysts, titanium dioxide (TiO₂) is one of the most investigated photocatalysts due to its non-toxicity, good stability, and low price (Cao et al., 2023; Haider et al., 2023). However, TiO₂ is not very responsive to visible light, seriously restricting its practical application. Therefore, it is of great necessity to develop a photocatalyst with high visible light responsive ability to enhance the utilization rate of solar energy.

Nowadays, numerous researchers have concentrated on the preparation of photocatalysts with narrow band gap and high-efficiency photogenerated carrier separation. Previous reports indicate that bismuth materials have promising applications in the field of photocatalysis due to their strong visible-light corresponding ability (Feng et al., 2022). Bismuth tungstate (Bi₂WO₆) is a kind of perovskite semiconductor material, which is characterized by good visible light excitation activity and suitable band gap energy (2.8 eV). Compared with other photocatalysts including BiVO₄ (Wang et al., 2022), CuO (Cao et al., 2021), MoS₂ (Lin et al., 2023), g-C₃N₄ (Mao et al., 2018; Wang et al., 2021a), CeO₂ (Huang et al., 2016b; Ye et al., 2019; Bai et al., 2020), and CuS (Mao et al., 2021b), Bi₂WO₆ not only effectively lowers the rapid recombination of photogenerated carriers, but also exhibits extreme stability, low environmental toxicity, and corrosive characteristic during the process of actual environmental application (Cao et al., 2021; Wang et al., 2022). Wang et al. extensively investigated the synthetic methods and the modification measures of Bi₂WO₆ to improve the photocatalytic performance of the composite (Wang et al., 2015; 2019; 2020b). To improve the photocatalytic performance of Bi₂WO₆ in environmental applications, Jiang et al. focused on enhancing the visible light response of Bi₂WO₆ by carbon doping modification (Jiang et al., 2023). The doping of nonmetallic elements, such as carbon, nitrogen, phosphorus, and sulfur, may form a strong electric field into the interface and show a more efficient photogenerated carrier transfer (Guo et al., 2023). Although numerous researches have already concentrated on the photocatalytic properties of Bi₂WO₆ and its application in environmental remediation (Fig.1), its comprehensive application in the fields of environmental remediation, medicine and clean energy has not yet been discussed. Therefore, reviewing and summarizing the current research results will exert a strong role in guiding the future synthesis of high-performance Bi₂WO₆-based photocatalytic composites. In this study, the photocatalytic properties and mechanism of Bi₂WO₆-based materials were also introduced. The photocatalytic performance of Bi₂WO₆-based material and its application in actual water were discussed. Finally, the potential research directions and applications of Bi₂WO₆-based materials in the future were prospected.

Fig.1 Graph showing the number of papers published annually on photocatalysis field by Bi2WO6 composites (Data extracted from Web of Science Database).

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2 Synthesis, structure, and characteristics of Bi₂WO₆

Recently, different preparation methods have been employed to synthesize Bi₂WO₆ nanoparticles to form different microstructure, including nano-flowers, hierarchical microsphere, nano-sheets, microspheres, nanorods, nano-plates, and nano-cuboids (Zhang et al., 2019; Wei et al., 2020; Orimolade et al., 2021). The morphology of Bi₂WO₆ influencing the photocatalytic abilities mainly is dependent on the synthesis methods (Meng et al., 2017). Up to now, the preparation methods of Bi₂WO₆ include hydrothermal synthesis, solvothermal, calcination, and electrodeposition (Hu et al., 2019; Wang et al., 2021b; 2023a). The preparation method tremendously determines the crystal lattice and morphology of Bi₂WO₆. For example, the hydrothermal reaction generally facilitates the formation of nano-like structure, while the calcination method usually results in an agglomerate structure, which may influence the photocatalytic performance by adjusting the number of active sites on the surface of the composite and the adsorption capacity of the treated object. Due to the large and stable specific surface area of the obtained composite, the hydrothermal/solvothermal method has been widely used to synthesize Bi₂WO₆ (Tab.1).

Tab.1 Summary of synthesis and photocatalytic properties of Bi2WO6

Photocatalyst	Synthesis method	Morphology	Specific surface area (m2/g)	Contaminant	Removal efficiency	Photocatalysis condition	Ref.
Bi2WO6	Hydrothermal	Nanoflowers	26.154	Ceftriaxone sodium	70.18%	C0 = 10 mg/L; t = 240 min; dosage = 1 g/L; LS: 300 W Xenon lamp	Zhao et al. (2018b)
Bi2WO6	Solvothermal	Nanosheets and microspheres	–	Rhodamine B	97%	C0 = 10 mg/L; t = 180 min; dosage = 0.2 g/L; LS: 420 W Xenon lamp	Ma et al. (2016)
Bi2WO6-g-C3N4	Microwave hydrothermal	Nanosheets	103.01	Atrazine	100%	C0 = 10 mg/L; t = 60 min; dosage = 0.8 g/L; LS: 500 W Xenon lamp	Yang et al. (2023a)
BPQD/BWO	Hydrothermal	Porous hollow spheres	67.03	Amoxicillin	94.5%	C0 = 20 mg/L; t = 60 min; dosage = 0.25 g/L; LS: 300 W Xenon lamp	Chen et al. (2023)
In2S3/Bi2WO6	Hydrothermal	Chrysanthemum-like	64.8	Tetracycline hydrochloride	96%	C0 = 20 mg/L; t = 120 min; dosage = 1 g/L; LS: 300 W Xenon lamp	He et al. (2022)
Bi2S3-Bi2WO6	Hydrothermal	Nanorods	–	Carbamazepine	92%	C0 = 5 mg/L; t = 30 min; dosage = 0.5 g/L; LS: 100 W Xenon lamp	Cheng et al. (2022)
CQDs/Bi2WO6	Hydrothermal	Petal-like	35.56	Tetracycline	89%	C0 = 20 mg/L; t = 40 min; dosage = 0.6 g/L; LS: 300 W Xenon lamp	Ren et al. (2023)
PPy/BWO	Solvothermal-calcining	Flower spherical	–	Cr(VI)	99.7%	C0 = 10 mg/L; t = 30 min; dosage = 0.15 g/L; LS: 300 W Xenon lamp	Song et al. (2022)

In many cases, the lattice and surface morphology of Bi₂WO₆ were regulated by adding surfactants, choosing different solvents, as well as controlling pH and temperature of the reaction system during synthesis. In the study performed by Mao et al. (2018), Bi₂WO₆ nanoparticles were prepared by adding sodium oleate with hydrothermal reaction (Fig.2(a)). Similarly, Yuan et al. (2019) fine-tuned the gas-sensitive properties and structure of Bi₂WO₆ nanoparticles during hydrothermal preparation by the addition of hexadecyl trimethyl ammonium chloride (CTAC) (Fig.2(b)). Ultra-thin nanosheets with a thickness of 6.5 nm were reassembled into a uniform three-dimensional layered nanoflower structures. It was found that the addition sequence of bismuth nitrate (Bi(NO₃)₃·5H₂O) and sodium tungstate made an impact on the synthesis of Bi₂WO₆, mainly due to the strong hydrolysis property of Bi(NO₃)₃·5H₂O. Moreover, the addition of CTAC would directly affect the assembly of Bi₂WO₆, and numerous atoms were generated at the crystal-amorphous boundary of the composite with excessive CATC. In the meanwhile, a three-dimensional microsphere of Bi₂WO₆ was effectively prepared by sol-gel hydrothermal method with EDTC as the reaction solvent (Liu et al., 2014). A nanoparticle of Bi₂WO₆ was synthesized by microwave-assisted pyrolysis in sequence (Phu et al., 2015). Zhao et al. (2018a) found that the Bi₂WO₆ exhibited a nanoflower morphology in a synthetic environment with a pH of 1–7, while the nanoplate structures dominated when the reaction liquid pH was 9–11 (Zhao et al., 2018a). Specifically, the structure of Bi₂WO₆ gradually changed from the nanoflowers, nodular, rod-like, and irregular shapes with the pH value of the reaction system ranging from 1 to 11, respectively. Bi₂WO₆ with a nanoflower structure exhibited the highest photocatalytic removal ability of ceftriaxone sodium, possibly due to the large specific surface area contributing to light capture. Moreover, microdisk, porous nanoplates, and ultrathin monolayer structures of Bi₂WO₆ can be synthesized by the assistance of acetic acid, egg white proteins (albumin), or the assistance of a cetyltrimethylammonium bromide, respectively (Yi et al., 2019). It is mainly caused by the fact that the addition of surfactants can lower the band gap energy of Bi₂WO₆, and hinder the accumulation of monolayer through coulomb repulsion, which may result in the production of unsaturated coordination and the active sites.

Fig.2 The synthetic path of Bi2WO6 (a and b), (c and d) SEM and (e) HRTEM images of Bi2WO6 microstructure. Reprinted from Ref. (Yuan et al., 2019; Mao et al., 2021a) with permission from Elsevier, Chinese Academy of Sciences, and National Natural Science Foundation of China.

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3 Modification of Bi₂WO₆

The intrinsic factors of influencing the photocatalytic performance of Bi₂WO₆ include the light absorption range, photoelectron migration rate, photogenerated carrier separation and recombination efficiency, band gap width, and the number of surface active sites (Bai et al., 2021; Zhang et al., 2023). Nevertheless, it is difficult for Bi₂WO₆ to fully satisfy the needs of photocatalysis, primarily due to its low visible light response, relatively wide band gap, and fast photogenerated electron-hole recombination. Therefore, it is essential to improve the photocatalytic performance of Bi₂WO₆ using a series of modification methods, including the construction of p-n heterojunction, carbon load, and atomic doping.

3.1 The construction of semiconductor heterojunction

The construction of semiconductor heterojunction is an effective modification method for Bi₂WO₆ enhancing the photocatalytic carrier separation efficiency and photocatalytic response. Semiconductor p-n heterojunction catalysts are generally formed by two or more P-type and N-type semiconductors closely linked through hydrothermal or other reactions. Meanwhile, the heterojunction interface of composite material promotes the effective separation of photogenerated electrons and holes, which may further enhance the photocatalytic performance. As shown in Fig.3, n-type semiconductor Bi₂WO₆ and p-type semiconductor BiFeO₃ successfully formed p-n heterojunction structure, possibly because of the electron migration from Bi₂WO₆ conduction band to BiFeO₃, which may lower and increase electron cloud density of Bi₂WO₆ and BiFeO₃, respectively. The photogenerated electrons transfer may induce the internal electric field to further promote the effective separation of photogenerated electron-hole, improving the photocatalytic performance of Bi₂WO₆/BiFeO₃. Similarly, through a simple hydrothermal reaction, the p-n heterojunction of Bi₂WO₆/BiOI was constructed (Xiang et al., 2016). XRD and XPS characterization indicate that p-n heterojunction of Bi₂WO₆/CuS has been successfully prepared by sodium oleate glycol system (Fig.4(a) and Fig.4(b)). The removal mechanism investigation showed that the photogenerated carrier directly oxidizes organic matter and reduces hexavalent chromium (Cr(VI)), as well as realizes the synchronous removal of Cr(VI) and organic matter (Fig.4(c)).

Fig.3 (a) Semiconductor heterojunction diagram of Bi2WO6/BiFeO3; Mechanism of photogenerated charge-separation and -migration (b), and photocatalytic degradation and oxygen evolution in Bi2WO6/BiFeO3 (c); Schematic diagram of charge separation and migration in (d) Bi2WO6/BiFeO3-1, (e) Bi2WO6/BiFeO3-2, and (f) Bi2WO6/BiFeO3-3 NFs. Reprinted from Ref. (Tao et al., 2020) with permission from Elsevier.

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Fig.4 (a) XRD patterns and (b) XPS spectra of photocatalysts; (c) photocatalytic removal mechanism of mixed RhB, TCH, and Cr(VI). Reprinted from Ref. (Mao et al., 2021b) with permission from Chinese Academy of Engineering and Tsinghua University.

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Although the construction of p-n heterojunction effectively improves the separation and migration of photogenerated carriers, the directional transfer of photogenerated holes to more negative valence bands and electrons to more corrected conduction bands will reduce the redox potentials of photon-induced carrier. Due to the electrostatic repulsion between the same charges, it is prevented from directional migration and enrichment of photogenerated electrons and holes (Chen et al., 2021). To overcome the p-n heterojunction defect, researchers have focused on a Z-type heterojunction similar to plant photosynthesis. During the process of heterogeneous structure construction, Z-type heterojunction can not only realize the efficient separation of photogenerated electrons and holes, but also maintain the original redox properties of photocatalyst.

In the Z-type heterogeneous structure construction, materials with strong conductivity are generally selected as electronic media, including metal atoms (Ni, Cu, Ag, and Au) and conductive carbon-rich materials (carbon nanotubes, graphene, carbon black, carbon fiber, and carbon quantum dots) (Li et al., 2018; Keerthana et al., 2020; Ng et al., 2020; Chen et al., 2021; Zhao et al., 2024a). A carbon quantum dot-decorated BiOBr/Bi₂WO₆ heterojunction was successfully synthesized with a mild hydrothermal method (Fig.5(a)), and nanoflower-like microspheres were obtained (Fig.5(b) and Fig.5(c)) (Zhang et al., 2022). Using a series of characterization and calculation, the valence and conduction bands of BiOBr were separately +1.20 and −1.49 eV, severally, and those of Bi₂WO₆ were +2.70 and −0.01 eV, respectively (Fig.5(d)). The photogenerated holes in the valence band of BiOBr can not directly produce hydroxyl radical, and the photoinduced electrons in the conduction band of Bi₂WO₆ can not react with oxygen to produce superoxide radicals (Fig.5(e)), mainly owing to the failure to reach the standard redox potential of hydroxyl radical and superoxide radical. Therefore, the introduction of carbon quantum dots lowers the band gap of CQDs/BiOBr/BWO by forming Z-type heterojunctions, which will further promote the effective separation of photogenerated carriers and inhibit the recombination of electron and holes (Fig.5(f)).

Fig.5 (a) Schematic representation of the fabrication of CQDs/BiOBr/BWO; SEM images of (b) BiOBr and (c) Bi2WO6; (d–f) Charge transfer modes of CQDs/BiOBr/BWO. Reprinted from Ref. (Zhang et al., 2022) with permission from The American Chemical Society.

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3.2 Carbon modification

Carbon-based materials are usually used as carriers of nanometer photocatalysts due to their rich carbon content, special electronic properties, conjugated π structure, and high electrical conductivity, which can act as a strong electron conductor and acceptor to promote electron migration and lower the recombination photogenerated carriers, remarkably improving the photocatalytic performance of the photocatalyst (Mao et al., 2022b; Kang et al., 2023; Yang et al., 2023b). Nowadays, numerous carbon-based materials have been widely used in the field of photocatalysis, including graphitic carbon nitride (g-C₃N₄), biochar (BC), graphene (PG), carbon nano tube, fullerene, and CQDs (Zhou and Zhu, 2012; Mao et al., 2018; Wang et al., 2020b; Li et al., 2021a; Zhao et al., 2022).

As a carbon-based material, g-C₃N₄ has exhibited excellent potential in photocatalysis due to its rich carbon nitrogen, simple preparation process, stable chemical structure, non-toxic and suitable band gap (Li et al., 2020c; Song et al., 2021; Ma et al., 2024). Bi₂WO₆/g-C₃N₄ nanoparticles were prepared by pyrolytic-hydrothermal reaction to realize carbon loading of nanoparticles and form p-n heterojunction interface, which is beneficial for the efficient separation of electrons and holes (Fig.6(a)–Fig.6(d)). Therefore, numerous active substances were produced, probably accelerating the degradation of organic pollutants. Moreover, Bi₂WO₆/g-C₃N₄ based multielement catalysts have been synthesized successively, including BWQ/g-C₃N₄/ATP (Zeng et al., 2022), SnTCPP/g-C₃N₄/Bi₂WO₆ (He et al., 2020), Bi₂WO₆/g-C₃N₄/CeO₂ (Bai et al., 2020), Bi₂WO₆/g-C₃N₄/BiFeO₃, and Bi₂WO₆/CuS/g-C₃N₄ (Bai et al., 2021). In addition, they can further increase the number of active sites and facilitate the separation of photogenerated electrons from holes because of the formation of multiple internal electric fields at the heterojunction interface.

Fig.6 SEM images of (a)–(b) Bi2WO6/g-C3N4; (c) XRD patterns and (d) HRTEM micrographs of Bi2WO6/g-C3N4; (e) Preparation flowchart of the fabrication of Bi2WO6/NSBC. Reprinted from Ref. (Mao et al., 2018; Mao et al., 2021a) with permission from Elsevier and SpringerLink.

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BC is a stable, carbon-rich, insoluble, porous, and fluffy substance formed by pyrolysis of biomass at varying temperatures under hypoxic or anaerobic conditions (Kochanek et al., 2022; Monisha et al., 2022). BC is of great interest due to its large specific surface area and wide range of raw materials, including agricultural waste (including peanut shell, pomelo peel, cotton straw, corn straw and animal manure), industrial organic waste, garden waste, and urban sludge (Osman et al., 2022). Therefore, BC has been chosen as the base material to modify Bi₂WO₆, which can enhance the adsorption and photocatalytic properties of the composite. Wang et al. modified BC by nitrogen doping and then loaded Bi₂WO₆ nanoparticles onto the porous carbon skeleton (BW/N-B) (Wang et al., 2020b). Due to the improved photoelectron migration efficiency and visible light response, the BW/N-B showed an extremely strong photocatalytic performance for the removal of RhB and Cr(VI). Moreover, N-doped BC has been shown to effectively improve the photocatalytic performance of Bi₂WO₆, possibly due to accelerated electron transfer through C-N bonds. To further improve the catalytic performance of Bi₂WO₆, N and S co-doped BC (NSBC) was prepared to disperse Bi₂WO₆. As displayed in Fig.7(a)–Fig.7(c), BC has a large specific surface area and Bi₂WO₆ nano-flowers were successfully loaded onto NSBC by hydrothermal reaction. The structure composition and chemical bond of elements of Bi₂WO₆ were not significantly changed after BC dispersion (Fig.7(d)–Fig.7(g)). Interestingly, photocurrent and electron hole separation rate were significantly increased by NSBC (Fig.7(h) and Fig.7(i)), probably due to the presence of graphite N, pyridine N, thiophene S, and oxidized S, providing numerous active sites, promoting electron migration, and improving the adsorption of pollutants.

Fig.7 SEM images of (a) BC, (b) NSBC1, (c) Bi2WO6/NSBC3; (d) XRD patterns of the different samples; (e) XPS survey scan, (f) N 1s, (g) C 1s of NSBC1; (h) Transient photocurrent responses and (i) PL spectra of synthesized photocatalysts. Reprinted from Ref. (Mao et al., 2021a) with permission from Elsevier.

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PG is usually used to construct photocatalytic materials due to its outstanding properties including stable chemical structure, fast carrier migration rate, and large specific surface area (Torres-Pinto et al., 2021). Cui et al. (2021) has successfully synthesized GQDs/BWO microspheres via hydrothermal reactions. The results showed that 10 GQDs/BWO had the best photocatalytic ability for degradation of nitrogen oxide (NO), and the conversion of NO by GQDs/BWO was 3.84 times higher than that by pure Bi₂WO₆, possibly owing to the excellent photogenerated electron transfer performance of GQDs (Cui et al., 2021). Additionally, Bi₂WO₆@GNRs nanocomposites were prepared by microwave assisted hydrothermal method, which not only had the excellent electron migration properties, but also exhibited an extremely strong sensing performance (Rajaji et al., 2018).

CQDs have attracted great attention due to its rich carbon content, non-toxicity, and strong photoresponse ability. Qian et al. combined highly stable CQDs with Bi₂WO₆ to enhance the photocatalytic oxidation of gaseous volatile organic compounds (VOCs) (Qian et al., 2016). CQDs/Bi₂WO₆ exhibited the absorption edge of visible light migration and promoted photogenerated carrier transfer, thus achieving efficient photocatalytic oxidation of toluene and acetone under both light and UV-light irradiation. Similarly, CQDs/Bi₂WO₆ was synthesized via in situ hydrothermal reaction, and demonstrated that the S-scheme heterojunction interface was connected by Bi-O-C bonds, providing an atomic-level interface channel for promoting photogenerated carrier migration (Ren et al., 2023). To investigate the interface mechanism of CQDs/m-Bi₂WO₆ from the microscopic level, density functional theory (DFT) calculation was employed to investigate the electronic properties of the interface structures (Wang et al., 2018a). As depicted in Fig.8(a)–Fig.8(c), in the interface, photogenerated electrons were accumulated in the CQDs region, while photoinduced holes were enriched in the Bi₂WO₆ region, primarily caused by the VB-edge hybridization and complementary conduction between CQDs and Bi₂WO₆. Meanwhile, CQDs can absorb near-infrared light (400–750 nm) to stimulate Bi₂WO₆ to form hole/electron pairs, and as an electron storage to capture photogenerated electrons emitted by Bi₂WO₆, suppressing electron and hole recombination (Fig.8(d) and Fig.8(e)). In summary, the modification of CQDs enhanced the photocatalytic removal of organic pollutants under visible light and infrared irradiation.

Fig.8 The distribution of partial charge density of valence band (a) and conduction band (b) of CQDs/m-Bi2WO6; (c) Deformation charge density of CQDs/m-Bi2WO6; (d) Schematic diagram of PL transformation in CQDs/m-Bi2WO6 heterojunction; (e) Photocatalytic mechanism diagram of CQDs/m-Bi2WO6 under visible and infrared light irradiation. Reprinted from Ref. (Wang et al., 2018a) with permission from The German Chemical Society.

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3.3 Atomic doping

Atomic doping can regulate the lattice of Bi₂WO₆, cause partial defects, improve the efficiency of electron and hole separation, and expand the absorption range of light. Atomic doping is categorized into nonmetallic (P, S, N, F, etc.) and metallic (Ag, Mo, Ce, Cd, Fe, etc.) element doping (Liu et al., 2021a).

The photocatalytic performance of the composites is positively influenced by nonmetallic element doping. Photocatalytic performance of S doped-g-C₃N₄/Bi₂WO₆ was explored by an ultrasonic approach (Murugan et al., 2021). The composite with 3 wt% S doping exhibits the highest photoelectric water oxidation performance, possibly due to the low charge recombination rate by forming heterostructure. Meanwhile, a novel N-CQDs/Bi₂WO₆ was also successfully constructed (Zhang et al., 2018b). Obviously, the photocatalysis and mineralization efficiency of N-CQDs/Bi₂WO₆ were significantly improved with nearly 97% (25 min) and 86.37% (90 min) removal of tetracycline, respectively. This was caused by the acceleration of charge transfer and improvement of molecular oxygen activation ability. Wang et al. (2020a) assisted the regulation of Bi₂WO₆ oxygen vacancy by iodine doping to introduce oxygen vacancy and induce photocatalytic oxidation of organochlorine pesticides. It was of note that the total organic carbon removal efficiency of sodium pentachlorophenol by iodine-doped Bi₂WO₆ was over 90% within 2 h, which was 10.6 times higher than that of Bi₂WO₆ under visible light. This is mainly caused by the fact that iodine doping weakens the introduction of sufficient oxygen vacancy in the Bi₂WO₆ lattice, thus significantly enhancing the molecular oxygen activity to degrade sodium pentachlorophenol. In addition, phosphorus-doped g-C₃N₄ modified Bi₂WO₆ and AgBr were successfully prepared using a simple in situ sedimentation-calcination-hydrothermal method (Xue et al., 2023). The removal efficiency of tetracycline by the composite reached 99.2% within 60 min, primarily because of the facilitation of photogenic carrier separation and low recombination rate based on the formation of mid-gap, Ag bridge, and multiple heterojunctions.

Metal doping improves the photocatalytic performance of composites through adjusting the band gap, and charge density distribution. Ding et al. reported that the photocatalytic removal efficiency of sodium pentachlorophenate was significantly enhanced by bismuth self-doping Bi₂WO₆ using a soft-chemical method (Ding et al., 2014). The results of structure characterization and DFT calculation indicated that bismuth self-doping Bi₂WO₆ improved photogenic carrier separation and transfer to produce more active substances. The introduction of Ti and Zr in Bi₂WO₆ resulted in structural defects and reduced the CB positions, enhancing visible-light responsiveness (Zhang et al., 2011; Arif et al., 2021). In brief, atom doping introduces defects to adjust the band gap and hole and significantly improves the photogenerated electrons and hole migration rate, aiming to increase the photocatalytic activity (Tab.2).

Tab.2 Comparison of photocatalytic properties of element doping Bi2WO6

Photocatalyst	Doping mode	Photocatalytic activity	Regulatory mechanism	Ref.
S, F-Bi2WO6	Nonmetallic	Methyl orange (MO) degradation: 95.4% (120 min) and Cr(VI) reduction: 94.3% (120 min)	Tuning oxygen vacancy	Peng et al. (2023)
CSs-Bi2WO6	Nonmetallic	TC degradation: 84.6% (60 min)	High visible light utilization	Jiang et al. (2023)
I0.50-Bi2WO6	Nonmetallic	Bisphenol A degradation: 78% (10 min)	Introducing reductive species I−	Xu et al. (2021)
N-CQDs/Bi2WO6	Nonmetallic	TC degradation: 97% (25 min)	Interfacial charge transfer	Zhang et al. (2018b)
Bi2 + XWO6	Metal	Sodium pentachlorophenate degradation: 97% (2.15 h)	Interfacial charge transfer	Ding et al. (2014)
Ti-Bi2WO6	Transition metal	Cr(VI) reduction: 100% (60 min)	Mediating oxygen vacancy	Arif et al. (2021)
Zr-Bi2WO6	Transition metal	RhB degradation: ~100% (20 min)	Mediating oxygen vacancy	Zhang et al. (2011)
Ag-Bi2WO6	Transition metal	RhB degradation: 94% (120 min)	Enhanced surface plasmon resonance	Phu et al. (2020)
Sm3+-Bi2WO6	Rare earth metal	RhB degradation: ~100% (40 min)	Tuning oxygen vacancy	Liu et al. (2020)
Yb-Bi2WO6	Rare earth metal	RhB degradation: 95% (180 min)	Introducing oxygen vacancies	Li et al. (2021b)
Eu-Bi2WO6	Rare earth metal	RhB degradation: 78% (60 min)	Influence morphology evolution	Xu et al. (2014)
Ba-Bi2WO6	Metal	RhB degradation: 96.3% (50 min)	Construction electron defect	Li et al. (2015)
La-Bi2WO6	Rare earth metal	RhB degradation: 90% (99 min)	Interfacial charge transfer	Ning et al. (2022)

4 Application of Bi₂WO₆-based materials in photocatalysis

4.1 Environmental remediation field

4.1.1 Degradation of organic pollutants

With the rapid development of industrial modernization, various organic pollutants, including pharmaceutical and personal care products (PPCPs), persistent organic pollutants (POPs), organic dyes, antibiotics, and pesticides, are constantly entering into the natural environment, posing serious environmental threats on human health and life (Chu et al., 2016; Huang et al., 2016a). As a novel energy-saving and environmental-friendly treatment method, photocatalysis has been considered as a prospective technology for the degradation of organic pollutants.

Zhao et al. (2024b) prepared an n-p type Bi₂WO₆/AgInS₂ S-type heterojunction based on hydrothermal method, and this Bi₂WO₆/AgInS₂ S-type heterojunction exhibited excellent photocatalytic activity for RhB, norfloxacin (NF), and levofloxacin (LEV) under visible light (Tab.3). Similarly, Guo et al. (2020) constructed Bi₂WO₆-BiOCl by hydrothermal reaction, revealing a highly efficient degradation pathway of oxytetracycline. Simultaneously, numerous Bi₂WO₆ based materials can remove multiple organic pollutants (Tab.3). The results are mainly attributed to the following two aspects: first, the separation and migration efficiency of photogenerated electrons and hole pairs significantly increased after the modification of Bi₂WO₆; secondly, the active substance was produced rapidly under the condition of light excitation. For example, Liu et al. (2022) constructed the Z-scheme Fe-g-CN/BiWO photo-Fenton system for efficient degradation of TC. In this study, the contribution of free radicals in organic degradation was determined by quenching experiment and EPR analysis. The TC degradation pathway of photo-Fenton system was indicated by LC-MS analysis (Fig.9(a)). With visible light excitation, photogenerated holes can react with H₂O to produce hydroxyl radicals, and O₂ was reduced by photo-induced electrons to generate superoxide radicals, thereby accelerating the oxidation of TC and interconversion between Fe(II) and Fe(III) to produce more free radicals (Fig.9(b)). Due to the high electron density, the amine groups, phenolic groups, and double bonds in the TC molecule were susceptible to be attacked by free radicals and holes (Wang et al., 2018b). Currently, pesticides have been widely used in agricultural production, causing excessive organic matter content in agricultural withdrawal water. GokulaKrishnan et al. (2024) anchored Bi₂WO₆ nanoparticles on the membrane by grafting through in situ polymerization for treating agricultural regression water.

Tab.3 Degradation of OP by Bi2WO6 based materials

Photocatalyst	Synthesis method	Photocatalytic activity	Photocatalysis condition	Ref.
Bi2WO6/AgInS2	Hydrothermal	RhB (92.24%, 60 min), NF (81.73%, 90 min), and LEV (87.46%, 90 min)	C0 = 10 mg/L; t = 90 min; dosage = 0.3 g/L; LS: 300 W Xenon lamp	Zhao et al. (2024b)
I-Bi/Bi2WO6	One-step solvothermal	Colorless BPA (30 mg/L, 93%), RhB (10 mg/L, 99.9%), anionic dye CoR (40 mg/L, 91%), sulfamethoxazole (SX, 10 mg/L, 55%), and atrazine (AZ, 10 mg/L, 60%)	t = 60 min; dosage = 0.2 g/L; LS: 300 W Xenon lamp	Hua et al. (2020)
Bi2WO6-BiOCl	Hydrothermal and solvothermal	Oxytetracycline (98.5%)	C0 = 20 mg/L; t = 80 min; dosage = 1 g/L; LS: 500 W Xenon lamp	Guo et al. (2020)
I0.30-Bi2WO6	Hydrothermal	2-chlorophenol (80%)	C0 = 10 mg/L; t = 300 min; dosage = 2 mg; LS: 150 W Xenon lamp	Wang et al. (2018c)
Oxygen vacancies enriched Bi2WO6	Solvothermal calcination	Decabromodiphenyl ether (BDE209, 98%)	C0 = 10 mg/L; t = 40 min; dosage = 0.3 g/L; LS: 300 W Xenon lamp	Yang et al. (2022)
CQD/BiOBr/Bi2WO6	Hydrothermal	Norfloxacin (k = 0.01717 min−1)	C0 = 15 mg/L; t = 120 min; dosage = 0.1 g/L; LS: 500 W Xenon lamp	Zhang et al. (2022)
Bi2WO6/RGO	Hydrothermal	RhB (99.5%), MO (78.5%), phenol (66.5%), SX (70.9%), and sulfanilamide (57.6%)	C0 = 10 mg/L; t = 8 h; dosage = 0.5 g/L; LS: natural sunlight	Dong et al. (2017)
Cu-Bi2WO6-Vo	One step solvothermal	TC (94%)	C0 = 20 mg/L; t = 30 min; dosage = 0.3 g/L; PMS = 0.3 g/L; LS: 300 W Xenon lamp	Zheng et al. (2023)

Fig.9 (a) Degradation path, and (b) photocatalytic removal mechanism of TC by composite materials. Reprinted from Ref. (Liu et al., 2022) with permission from Elsevier.

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4.1.2 Cr(VI) photocatalytic removal

As highly toxic substances, Cr(VI), may harm human health and damage the ecological environment. Meanwhile, Cr(VI) is 200 times more toxic than Cr(III) (Zhang et al., 2020b; Mao et al., 2022a). The photoelectrons and holes produced by photoexcitation can effectively lower Cr(VI), which has been regarded as a promising technology to address Cr(VI) pollution.

Arif et al. developed interface engineering of α-MnO₂/Bi₂WO₆ and regulated defect active sites for efficient photocatalytic reduction of Cr(VI) and degradation of TC (Fig.10(a)) (Arif et al., 2023). The photoinduced charge separation and conversion of α-MnO₂/Bi₂WO₆ were significantly enhanced by surface oxygen vacancies and defective sites Mn(III)/Mn(IV). As displayed in Fig.10(b), photoexcitation led to the generation of an internal electric field at the heterojunction interface, which could accelerate the migration of photogenerated electrons to the conduction band of α-MnO₂ and holes to the valence band of Bi₂WO₆. In this case, the electrons in the conduction band of α-MnO₂ can directly reduce Cr(VI), while the holes in the valence band of Bi₂WO₆ would probably be capable of producing hydroxyl radicals and oxidize TC, according to the previous study of Bi₂WO₆/CuS (Mao et al., 2021b). Z-scheme PPy/ Bi₂WO₆ composites were synthesized through a polymerization and deposition reaction (Fig.10(c)) (Song et al., 2022). Due to the internal electric field, the photogenerated electrons on the conduction band of Bi₂WO₆ quickly transferred to the contact interface and reunited with holes on the highest occupied molecular orbital of PPy, promoting the efficient separation and migration of photogenerated carriers on the valence band of Bi₂WO₆ and lowest unoccupied molecular orbital of PPy to produce free radicals. In summary, the photogenerated electrons and free radicals contributed to the reduction of Cr(VI).

Fig.10 (a) Preparation flowchart and (b) photocatalytic charge transfer mechanism at internal interface α-MnO2/Bi2WO6 heterostructure; Schematic diagram of (c) photocatalyst preparation of PPy/Bi2WO6. Reprinted from Ref. (Song et al., 2022; Arif et al., 2023) with permission from Elsevier.

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Bi₂WO₆ based materials can produce photoelectrons and holes in the photocatalytic reaction, which are characterized by strong reduction and oxidation properties, respectively. Therefore, it can achieve simultaneous oxidation of organic pollutants and detoxification of Cr(VI) in the reaction system. Meanwhile, the photogenic carrier reacts with water and dissolved oxygen to produce free radicals, which can possibly further promote the reduction of Cr(VI). Obviously, the synchronous removal of organic pollutants and Cr(VI) was significantly enhanced in the photocatalytic system. The results are primarily caused by the simultaneous consumption of photogenerated electrons and holes, accelerating the generation and migration of photogenerated carriers (Mao et al., 2021b). As displayed in Fig.11Bi₂WO₆ supported on nitrogen-sulfur co-doped BC by solvothermal reaction may promote the efficient transfer of photogenerated electrons, probably accelerating the oxidation of organic matter at the valence band and the reduction of Cr(VI) on the modified BC (Mao et al., 2021a). Similarly, Cai et al. (2023) reported that Bi₂WO₆/C₃N₄/carbon fiber cloth with oxygen vacancy (OV)-rich exhibited an excellent photocatalytic performance for removing antibiotics and Cr(VI).This is mainly resulted from the enhanced active center and accelerated charge carrier disintegration rate by constructing a fiber-shaped S-scheme photosystem with OVs.

Fig.11 Possible mechanism for photocatalytic removal of antibiotics and Cr(VI) on Bi2WO6/NSBC. Reprinted from Ref. (Mao et al., 2021a) with permission from Elsevier.

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4.2 Clean energy field

4.2.1 Reduction of CO₂ to high value-added products

Excessive CO₂ emissions from human activities have caused more extreme and frequent weather events including high temperature heat waves, dust storms in some regions, typhoons, and droughts (Hung et al., 2022). Bi₂WO₆-based materials can convert CO₂ into high value-added products under natural light such as CH₄, CH₃OH, CO, HCOOH, and C₂H₅OH (Fig.12) (Jiang et al., 2017; Li et al., 2020b; Liu et al., 2021b; Collado et al., 2023; Zhao et al., 2024a). During the process of photocatalytic CO₂ reduction, the photogenerated electrons are consumed to reduce CO₂, and the photogenic holes undergo water oxidation reactions. The two C = O (750 kJ/mol) bonds of CO₂ have obviously high bond energies when compared with the C–H (430 kJ/mol) and C–C (336 kJ/mol) bond (Wu et al., 2017; Shang et al., 2023). Therefore, the photocatalytic CO₂ reduction process needs to provide sufficient energy for ensuring that the reaction goes smoothly. As a result, the modification of Bi₂WO₆ has been widely used with two strategies being included. The photocatalytic performance of Bi₂WO₆ was improved by boosting photoabsorption, local surface plasmon resonance, and metallic photocatalysts, improving carrier separation capability, controlling the microscopic morphology, and so on (Zhao et al., 2023). Lu et al. (2021) constructed surface plasmon resonance on Bi₂WO₆ by electron doping to promote CO₂ selective reduction. It is of note that during the preparation and modification of Bi₂WO₆, the conduction band position should be lower than the reduction potential of CO₂, while the valence band position should be higher than the oxidation potential of H₂O (Zhang et al., 2012). In addition, the contact efficiency between Bi₂WO₆ and CO₂ was enhanced by improving the specific surface area and surface structure. Liu et al. (2021c) constructed a hydrophobic Bi₂WO₆ nanosheets by hexadecyl trimethyl ammonium bromide modification, significantly improving the adsorption and mass-transfer of CO₂ on the surface of Bi₂WO₆. Wang et al. (2023b) designed inner-to-outer tandem homojunctions through gradient cationic vacancies, which may significantly enhance W-vacant Bi₂WO₆ photoreduction of CO₂ through strong local internal electric field and reformed basic sites.

Fig.12 Schematic diagram of photocatalytic CO2 reduction mechanism: (a) ultrathin 2Ag-BWO nanosheets, (b) QDh-Bi2WO6, (c) chloride-modified Bi2WO6, and (d) Bi2WO6/TiO2. Reprinted from Ref. (Jiang et al., 2017; Li et al., 2020b; Collado et al., 2023; Zhao et al., 2024a) with permission from Elsevier, The Royal Society of Chemistry, and Catalysis Society of Chinese Chemical Society, respectively.

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4.2.2 Solar hydrogen production

Owing to its thin two-dimensional structure and electron-dominated lattice, Bi₂WO₆ has the potential to efficiently produce hydrogen gas. The redox potential and suitable band gap of Bi₂WO₆ are the vital factors for hydrogen evolution (Fig.13) (Wu et al., 2020; Yan et al., 2022). Xing et al. (2019) synthesized ultrathin 2D-2D heterojunctions Bi₂WO₆-Bi₂O₂S through a simple two-step hydrothermal method. A five-alternating-layer sandwich structure was formed by in situ growing of Bi₂O₂S, which could not only promote the interfacial charge transfer but also significantly improve the photocatalytic water decomposition efficiency. Some researchers assembled Bi₂WO₆ with other materials due to its excellent optical properties, improving the photocatalytic hydrogen evolution performance of composite materials. Hu et al. (2019) succeeded in introducing black phosphorus into Bi₂WO₆ (BP-Bi₂WO₆) to break down water molecules in the air. The photocatalytic hydrogen evolution rate of BP-Bi₂WO₆ was significantly improved, and was 9.15 times higher than that of pure Bi₂WO₆. Likewise, Murugan et al. (2021) designed S doped-g-C₃N₄/Bi₂WO₆ heterojunction by ultrasonic method. S doped-g-C₃N₄ was combined to form heterojunction structure, thereby accelerating the separation of photogenerated electron-hole pairs, and boosting the water oxidation kinetics on the surface of S doped-g-C₃N₄/Bi₂WO₆.

Fig.13 Schematic diagram of photocatalytic hydrogen production: (a) MBWO and (b) BP-Bi2WO6. Reprinted from Ref. (Hu et al., 2019; Wu et al., 2020) with permission from The American Chemical Society and The German Chemical Society.

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4.2.3 Ammonia synthesis by nitrogen photocatalytic reduction

Ammonia is a particularly important chemical product in the rapid development of the current industrialization, and has been widely used in agriculture, industry, and military fields. The Haber–Bosch method has been applied in industrial production to synthesize ammonia, which not only consumes 2% of global energy, but also accounts for 1% of the world’s annual CO₂ emissions. However, photocatalytic nitrogen fixation refers to the use of abundant clean solar energy input to produce ammonia, obviously meeting the clean production. Dhanaraman et al. (2024) reasonably inserted a Bi₂WO₆ into g-C₃N₄ to enhance photocatalytic antibiotic removal and nitrogen reduction reactions. Verma et al. (2023) successfully optimized the Bi₂WO₆–BiOCl heterojunctions by varying the molar ratio of chlorine: tungsten precursor. The ammonia yield of the Bi₂WO₆–BiOCl was 345.1 umol/(L·h), which was 2.6 and ~2 times higher than that of the original Bi₂WO₆ and BiOCl, respectively. To improve the efficiency of ammonia synthesis, numerous studies have chosen to combine photocatalysis with electrocatalysis to achieve efficient nitrogen reduction of ammonia production. Yang et al. (2021) doped cerium into Bi₂WO₆ by a defection-induced manner for electrochemical nitrogen reduction of ammonia production.

4.3 Medical science field

The Bi₂WO₆ nanoparticles had an extremely surface activity for photocatalytic oxidation reactions, producing active substances (·O₂^–, ·OH, and ¹O₂) under light excitation in the range of ultraviolet to near-infrared (Zhou et al., 2015). Thus, many researchers have applied Bi₂WO₆ in photodynamic therapy of tumor (Fig.14). Wang et al. indicated that Bi₂WO₆ could generate an active substance in the absence of oxygen consumption, opening up novel ideas for oxygen-free photodynamic treatment of tumors (Zhang et al., 2018a). Meanwhile, the Bi₂WO₆ nanoparticles were hired considering their capacity to induce both oxygen-independent type I photodynamic therapy and photothermal therapy (Zhang et al., 2018a). Zhang et al. (2020a) constructed a hybrid by loading oxygen-independent photodynamic Bi₂WO₆ onto a platelet membrane (PM-Bi₂WO₆ NPs). After the hybrid entered the tumor cells, photoexcited Bi₂WO₆ produces enormous quantities of active substances through photodynamic and photothermal processes, which could not only destroy platelet membranes in hypoxic conditions but also overcome the immunosuppression induced by myeloid-derived suppressor cells. Ding et al. synthesized oxygen-deficient and iron-doped Bi₂WO₆ nanosheets (BWO-Fe NSs) with Fenton reaction for enhanced sonodynamic therapy against breast cancer (Ding et al., 2023).

Fig.14 Schematic diagram of anti-tumor mechanism: (a) Bi2WO6-DOX-PEG NSs and (b) PM-BiW NPs. Reprinted from Ref. (Feng et al., 2018; Zhang et al., 2020a) with permission from Elsevier, and Wiley, respectively.

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5 Summary and future perspective

5.1 Summary

In this study, the photocatalytic properties of Bi₂WO₆-based materials were improved through adjusting the surface morphology, band gap and electron migration. In addition, the advanced applications in the fields of environmental pollution remediation, life medicine and clean energy were reviewed. The continuous breakthrough of controllable preparation and modification nano-structured Bi₂WO₆-based materials, including atomic doping, carbon loading and heterostructural construction, has brought specific surface area, photoelectron-hole migration ability, visible light response range and band gap width, etc., thus exerting a significant role in improving photocatalytic performance.

Since the photocatalytic properties of Bi₂WO₆-based materials are primarily influenced by photoelectron-hole migration and visible light absorption range, the effective improvement on their surface structure and bonding bonds are vital factors to determine the photocatalytic performance. For example, the successful loading of Bi₂WO₆ on the modified carbon-based material may achieve effective photogenic electron transfer and adsorption-removal of pollutants in the composite material, exhibiting strong chemical and structural advantages. The photocatalytic process produces strong oxidizing holes, which can achieve efficient removal of organic matter. In addition, the photogenerated electrons formed may achieve CO₂ reduction and water decomposition, effectively realizing the conversion of solar energy to chemical energy. During the photocatalytic process, the Bi₂WO₆-based material will release numerous active substances, which can also be used as a medium for tumor photodynamic therapy.

5.2 Future perspective

However, there are still some shortcomings in the research of Bi₂WO₆-based materials. The existing limitations should be further considered in the future studies.

1) Machine learning is expected to be incorporated into the construction process of Bi₂WO₆-based materials to assist in modifying photocatalysts in a data-driven manner, which can realize full exposure of active sites in the structure of Bi₂WO₆ perovskite.

2) Although atomic modulation can change the photocatalytic performance of Bi₂WO₆, it is difficult to accurately regulate the atomic sites. Therefore, it is essential to employ reasonable design and advanced characterization techniques to further show the mechanism of atomic sites in the photocatalytic reaction.

3) The modification of Bi₂WO₆-based materials mainly improves the electron and hole migration rate of composites. However, the mechanism of photogenerated carrier migration at the interface remains controversial. Therefore, the in situ characterization method needs to be developed to analyze the interfacial charge dynamics and identify the photogenerated electron-hole migration process at the interfacial of Bi₂WO₆-based materials.

4) The photocatalytic process mainly depends on the oxidation or reduction of photogenerated carrier, while the contact between Bi₂WO₆-based materials and water is limited. Thus, the active substances decrease one by one with the distance during the reaction. Moreover, it is essential to introduce an intermediate medium that can act as an energy medium to satisfy the homogeneous redox reaction in the system.

5) To improve the treatment effect, Bi₂WO₆-based materials may be effectively combined with electrocatalysis, ultrasonic and thermal catalysis to further enhance the release of active substances and photocatalytic activity.

References

[1] Arif M , Mahsud A , Ali A , Liao S , Xia J , Xiao H , Azam M , Muhmood T , Lu Z , Chen Y . (2023). Unraveling the synergy of interface engineering α-MnO₂/Bi₂WO₆ heterostructures and defective active sites for superdurable photocatalysis: mechanistic insights into charge separation/transfer. Chemical Engineering Journal, 475: 146458

[2] Arif M , Zhang M , Mao Y , Bu Q , Ali A , Qin Z , Muhmood T , Shahnoor X , Liu B , Zhou S . (2021). Oxygen vacancy mediated single unit cell Bi₂WO₆ by Ti doping for ameliorated photocatalytic performance. Journal of Colloid and Interface Science, 581: 276–291

[3] Bai Y , Mao W , Wu Y , Gao Y , Wang T , Liu S . (2021). Synthesis of novel ternary heterojunctions via Bi₂WO₆ coupling with CuS and g-C₃N₄ for the highly efficient visible-light photodegradation of ciprofloxacin in wastewater. Colloids and Surfaces. A, Physicochemical and Engineering Aspects, 610: 125481

[4] Bai Y , Wang T , Zhao X , Mao W , Liu S . (2020). Synthesis of novel ternary Bi₂WO₆/CeO₂/g-C₃N₄ composites with enhanced visible light photocatalytic activity for removal of organic and Cr(VI) from wastewater. Journal of Materials Science Materials in Electronics, 31(20): 17524–17534

[5] Cai M , Liu Y , Dong K , Chen X , Li S . (2023). Floatable S-scheme Bi₂WO₆/C₃N₄/carbon fiber cloth composite photocatalyst for efficient water decontamination. Chinese Journal of Catalysis, 52: 239–251

[6] Cao H , Liu F , Tai Y , Wang W , Li X , Li P , Zhao H , Xia Y , Wang S . (2023). Promoting photocatalytic performance of TiO₂ nanomaterials by structural and electronic modulation. Chemical Engineering Journal, 466: 143219

[7] Cao X , Yue L , Lian F , Wang C , Cheng B , Lv J , Wang Z , Xing B . (2021). CuO nanoparticles doping recovered the photocatalytic antialgal activity of graphitic carbon nitride. Journal of Hazardous Materials, 403: 123621

[8] Chen L , Wang C , Liu G , Su G , Ye K , He W , Li H , Wei H , Dang L . (2023). Anchoring black phosphorous quantum dots on Bi₂WO₆ porous hollow spheres: a novel 0D/3D S-scheme photocatalyst for efficient degradation of amoxicillin under visible light. Journal of Hazardous Materials, 443: 130326

[9] Chen T , Liu L , Hu C , Huang H . (2021). Recent advances on Bi₂WO₆-based photocatalysts for environmental and energy applications. Chinese Journal of Catalysis, 42(9): 1413–1438

[10] Cheng Y , Chen J , Wang P , Liu W , Che H , Gao X , Liu B , Ao Y . (2022). Interfacial engineering boosting the piezocatalytic performance of Z-scheme heterojunction for carbamazepine degradation: Mechanism, degradation pathway and DFT calculation. Applied Catalysis B: Environmental, 317: 121793

[11] Chu X , Shan G , Chang C , Fu Y , Yue L , Zhu L . (2016). Effective degradation of tetracycline by mesoporous Bi₂WO₆ under visible light irradiation. Frontiers of Environmental Science & Engineering, 10(2): 211–218

[12] Collado L , Gomez-Mendoza M , García-Tecedor M , Oropeza F E , Reynal A , Durrant J R , Serrano D P , de la Peña O’Shea V A . (2023). Towards the improvement of methane production in CO₂ photoreduction using Bi₂WO₆/TiO₂ heterostructures. Applied Catalysis B: Environmental, 324: 122206

[13] Cui Y , Wang T , Liu J , Hu L , Nie Q , Tan Z , Yu H . (2021). Enhanced solar photocatalytic degradation of nitric oxide using graphene quantum dots/bismuth tungstate composite catalysts. Chemical Engineering Journal, 420: 129595

[14] Dhanaraman E , Verma A , Chen P H , Chen N D , Siddiqui Y , Fu Y P . (2024). Bi₂WO₆ incorporation of g-C₃N₄ to enhance the photocatalytic N₂ reduction reaction and antibiotic pollutants removal. Solar RRL, 8: 2300981

[15] Ding X , Zhao K , Zhang L . (2014). Enhanced photocatalytic removal of sodium pentachlorophenate with self-doped Bi₂WO₆ under visible light by generating more superoxide ions. Environmental Science & Technology, 48(10): 5823–5831

[16] Ding Y , Zhao Y , Yao S , Wang S , Wan X , Hu Q , Li L . (2023). Enhanced sonodynamic cancer therapy through iron–doping and oxygen–vacancy engineering of piezoelectric bismuth tungstate nanosheets. Small, 19(24): 2300327

[17] Dong S , Ding X , Guo T , Yue X , Han X , Sun J . (2017). Self-assembled hollow sphere shaped Bi₂WO₆/RGO composites for efficient sunlight-driven photocatalytic degradation of organic pollutants. Chemical Engineering Journal, 316: 778–789

[18] Fehr A M K , Agrawal A , Mandani F , Conrad C L , Jiang Q , Park S Y , Alley O , Li B , Sidhik S , Metcalf I . . (2023). Integrated halide perovskite photoelectrochemical cells with solar-driven water-splitting efficiency of 20.8%. Nature Communications, 14(1): 3797

[19] Feng L , Yang D , Gai S , He F , Yang G , Yang P , Lin J . (2018). Single bismuth tungstate nanosheets for simultaneous chemo-, photothermal, and photodynamic therapies mediated by near-infrared light. Chemical Engineering Journal, 351: 1147–1158

[20] Feng X , Zheng R , Gao C , Wei W , Peng J , Wang R , Yang S , Zou W , Wu X , Ji Y . . (2022). Unlocking bimetallic active sites via a desalination strategy for photocatalytic reduction of atmospheric carbon dioxide. Nature Communications, 13(1): 2146

[21] GokulaKrishnan S A , Arthanareeswaran G , Devi D R . (2024). Bi₂WO₆ nanoparticles anchored on membrane by grafting via in-situ polymerization for the treatment of antibiotic and pesticides wastewater. Chemosphere, 351: 141214

[22] Guo M , Zhou Z , Yan S , Zhou P , Miao F , Liang S , Wang J , Cui X . (2020). Bi₂WO₆–BiOCl heterostructure with enhanced photocatalytic activity for efficient degradation of oxytetracycline. Scientific Reports, 10(1): 18401

[23] Guo X , Zhang F , Zhang Y , Hu J . (2023). Review on the advancement of SnS₂ in photocatalysis. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 11(14): 7331–7343

[24] Haider S , Nawaz R , Anjum M , Haneef T , Oad V K , Uddinkhan S , Khan R , Aqif M . (2023). Property-performance relationship of core-shell structured black TiO₂ photocatalyst for environmental remediation. Frontiers of Environmental Science & Engineering, 17(9): 111

[25] He Y , Lv H , Daili Y , Yang Q , Junior L B , Liu D , Liu H , Ma Z . (2020). Construction of a new cascade photogenerated charge transfer system for the efficient removal of bio-toxic levofloxacin and Rhodamine B from aqueous solution: mechanism, degradation pathways and intermediates study. Environmental Research, 187: 109647

[26] He Z , Siddique M S , Yang H , Xia Y , Su J , Tang B , Wang L , Kang L , Huang Z . (2022). Novel Z-scheme In₂S₃/Bi₂WO₆ core-shell heterojunctions with synergistic enhanced photocatalytic degradation of tetracycline hydrochloride. Journal of Cleaner Production, 339: 130634

[27] Hu J , Chen D , Mo Z , Li N , Xu Q , Li H , He J , Xu H , Lu J . (2019). Z-scheme 2D/2D eterojunction of black phosphorus/monolayer Bi₂WO₆ nanosheets with enhanced photocatalytic activities. Angewandte Chemie International Edition, 58(7): 2073–2077

[28] Hua C , Wang J , Dong X , Wang Y , Zheng N , Xue M , Zhang X . (2020). In situ plasmonic Bi grown on I-doped Bi₂WO₆ for enhanced visible-light-driven photocatalysis to mineralize diverse refractory organic pollutants. Separation and Purification Technology, 250: 117119

[29] Huang Y , Fan W , Long B , Li H , Zhao F , Liu Z , Tong Y , Ji H . (2016a). Visible light Bi₂S₃/Bi₂O₃/Bi₂O₂CO₃ photocatalyst for effective degradation of organic pollutions. Applied Catalysis B: Environmental, 185: 68–76

[30] Huang Y , Guo Z , Liu H , Zhang S , Wang P , Lu J , Tong Y . (2019). Heterojunction architecture of N-doped WO₃ nanobundles with Ce₂S₃ nanodots hybridized on a carbon textile enables a highly efficient flexible photocatalyst. Advanced Functional Materials, 29(45): 1903490

[31] Huang Y , Long B , Tang M , Rui Z , Balogun M S , Tong Y , Ji H . (2016b). Bifunctional catalytic material: an ultrastable and high-performance surface defect CeO₂ nanosheets for formaldehyde thermal oxidation and photocatalytic oxidation. Applied Catalysis B: Environmental, 181: 779–787

[32] Hung S F , Xu A , Wang X , Li F , Hsu S H , Li Y , Wicks J , Cervantes E G , Rasouli A S , Li Y C . . (2022). A metal-supported single-atom catalytic site enables carbon dioxide hydrogenation. Nature Communications, 13(1): 819

[33] Jiang X , Chen S , Zhang X , Qu L , Qi H , Wang B , Xu B , Huang Z . (2023). Carbon-doped flower-like Bi₂WO₆ decorated carbon nanosphere nanocomposites with enhanced visible light photocatalytic degradation of tetracycline. Advanced Composites and Hybrid Materials, 6(1): 47

[34] Jiang Z , Liang X , Zheng H , Liu Y , Wang Z , Wang P , Zhang X , Qin X , Dai Y , Whangbo M H . . (2017). Photocatalytic reduction of CO₂ to methanol by three-dimensional hollow structures of Bi₂WO₆ quantum dots. Applied Catalysis B: Environmental, 219: 209–215

[35] Kang F , Jiang X , Wang Y , Ren J , Xu B B , Gao G , Huang Z , Guo Z . (2023). Electron-rich biochar enhanced Z-scheme heterojunctioned bismuth tungstate/bismuth oxyiodide removing tetracycline. Inorganic Chemistry Frontiers, 10(20): 6045–6057

[36] Keerthana S P , Rani B J , Ravi G , Yuvakkumar R , Hong S I , Velauthapillai D , Saravanakumar B , Thambidurai M , Dang C . (2020). Ni doped Bi₂WO₆ for electrochemical OER activity. International Journal of Hydrogen Energy, 45(38): 18859–18866

[37] Kochanek J , Soo R M , Martinez C , Dakuidreketi A , Mudge A M . (2022). Biochar for intensification of plant-related industries to meet productivity, sustainability and economic goals: a review. Resources, Conservation and Recycling, 179: 106109

[38] Li C , Zhao Z , Fu S , Wang X , Ma Y , Dong S . (2021a). Polyvinylpyrrolidone in the one-step synthesis of carbon quantum dots anchored hollow microsphere Bi₂WO₆ enhances the simultaneous photocatalytic removal of tetracycline and Cr(VI). Separation and Purification Technology, 270: 118844

[39] Li J , Liang Z , Qin Y , Guo L , Lei N , Song Q . (2018). Defective Bi₂WO₆-supported Cu nanoparticles as efficient and stable photoelectrocatalytic for water splitting in near-neutral media. Energy Technology, 6(11): 2247–2255

[40] Li K , Lu X , Zhang Y , Liu K , Huang Y , Liu H . (2020a). Bi₃TaO₇/Ti₃C₂ heterojunctions for enhanced photocatalytic removal of water-borne contaminants. Environmental Research, 185: 109409

[41] Li W T , Huang W Z , Zhou H , Yin H Y , Zheng Y F , Song X C . (2015). Synthesis and photoactivity enhancement of Ba doped Bi₂WO₆ photocatalyst. Materials Research Bulletin, 64: 432–437

[42] Li X , Li W , Gu S , Liu X , Li H , Ren C , Ma X , Zhou H . (2021b). Efficient ytterbium-doped Bi₂WO₆ photocatalysts: synthesis, the formation of oxygen vacancies and boosted superoxide yield for enhanced visible-light photocatalytic activity. Journal of Alloys and Compounds, 851: 156935

[43] Li Y Y , Fan J S , Tan R Q , Yao H C , Peng Y , Liu Q C , Li Z J . (2020b). Selective photocatalytic reduction of CO₂ to CH₄ modulated by chloride modification on Bi₂WO₆ nanosheets. ACS Applied Materials & Interfaces, 12(49): 54507–54516

[44] Li Y , Gu M , Zhang X , Fan J , Lv K , Carabineiro S A C , Dong F . (2020c). 2D g-C₃N₄ for advancement of photo-generated carrier dynamics: Status and challenges. Materials Today, 41: 270–303

[45] Lin K T , Cheng W H , Cheng H L , Lin H H , Chou W Y , Hsu B Y , Mao C A , Hou Y C , Ruan J . (2023). Photocatalytic hydrogen evolution enabled by oriented phase interactions between monolayers of P3HT-wrapped MoS₂ and ferroelectric lamellar crystals. Advanced Functional Materials, 34: 2307262

[46] Liu C , Dai H , Tan C , Pan Q , Hu F , Peng X . (2022). Photo-Fenton degradation of tetracycline over Z-scheme Fe-g-C₃N₄/Bi₂WO₆ heterojunctions: mechanism insight, degradation pathways and DFT calculation. Applied Catalysis B: Environmental, 310: 121326

[47] Liu L , Liu J , Sun K , Wan J , Fu F , Fan J . (2021a). Novel phosphorus-doped Bi₂WO₆ monolayer with oxygen vacancies for superior photocatalytic water detoxication and nitrogen fixation performance. Chemical Engineering Journal, 411: 128629

[48] Liu S , Wang C , Wu J , Tian B , Sun Y , Lv Y , Mu Z , Sun Y , Li X , Wang F . . (2021b). Efficient CO₂ electroreduction with a monolayer Bi₂WO₆ through a metallic intermediate surface state. ACS Catalysis, 11(20): 12476–12484

[49] Liu X , Zhao Y , Ni Y , Shi F , Guo X , Li C . (2023). Hydroxylated organic semiconductors for efficient photovoltaics and photocatalytic hydrogen evolution. Energy & Environmental Science, 16(9): 4065–4072

[50] Liu Y , Shen D , Zhang Q , Lin Y , Peng F . (2021c). Enhanced photocatalytic CO₂ reduction in H₂O vapor by atomically thin Bi₂WO₆ nanosheets with hydrophobic and nonpolar surface. Applied Catalysis B: Environmental, 283: 119630

[51] Liu Y , Tang H , Lv H , Li Z , Ding Z , Li S . (2014). Self-assembled three-dimensional hierarchical Bi₂WO₆ microspheres by sol–gel–hydrothermal route. Ceramics International, 40(4): 6203–6209

[52] Liu Z , Liu X , Wei L , Yu C , Yi J , Ji H . (2020). Regulate the crystal and optoelectronic properties of Bi₂WO₆ nanosheet crystals by Sm³⁺ doping for superior visible-light-driven photocatalytic performance. Applied Surface Science, 508: 145309

[53] Lu C , Li X , Wu Q , Li J , Wen L , Dai Y , Huang B , Li B , Lou Z . (2021). Constructing surface plasmon resonance on Bi₂WO₆ to boost high-selective CO₂ reduction for methane. ACS Nano, 15(2): 3529–3539

[54] Ma D , Zhang Z , Zou Y , Chen J , Shi J W . (2024). The progress of g-C₃N₄ in photocatalytic H₂ evolution: from fabrication to modification. Coordination Chemistry Reviews, 500: 215489

[55] Ma Y , Liu Q , Wang Q , Qu D , Shi J . (2016). Insight into the origin of photoreactivity of various well-defined Bi₂WO₆ crystals: exposed heterojunction-like surface and oxygen defects. RSC Advances, 6(23): 18916–18923

[56] Mao W , Wang T , Wang H , Zou S , Liu S . (2018). Novel Bi₂WO₆ loaded g-C₃N₄ composites with enhanced photocatalytic degradation of dye and pharmaceutical wastewater under visible light irradiation. Journal of Materials Science Materials in Electronics, 29(17): 15174–15182

[57] Mao W , Zhang L , Liu Y , Wang T , Bai Y , Guan Y . (2021a). Facile assembled N, S-codoped corn straw biochar loaded Bi₂WO₆ with the enhanced electron-rich feature for the efficient photocatalytic removal of ciprofloxacin and Cr(VI). Chemosphere, 263: 127988

[58] Mao W , Zhang L , Wang T , Bai Y , Guan Y . (2021b). Fabrication of highly efficient Bi₂WO₆/CuS composite for visible-light photocatalytic removal of organic pollutants and Cr(VI) from wastewater. Frontiers of Environmental Science & Engineering, 15(4): 52

[59] Mao W , Zhang L , Zhang Y , Guan Y . (2022a). Simultaneous removal of arsenite and cadmium by a manganese-crosslinking sodium alginate modified biochar and zerovalent iron composite from aqueous solutions. Environmental Science. Nano, 9(1): 214–228

[60] Mao W , Zhang L , Zhang Y , Wang Y , Wen N , Guan Y . (2022b). Adsorption and photocatalysis removal of arsenite, arsenate, and hexavalent chromium in water by the carbonized composite of manganese-crosslinked sodium alginate. Chemosphere, 292: 133391

[61] Mao W , Zhang Y , Luo J , Chen L , Guan Y . (2022c). Novel co-polymerization of polypyrrole/polyaniline on ferrate modified biochar composites for the efficient adsorption of hexavalent chromium in water. Chemosphere, 303: 135254

[62] Meng X , Li Z , Zeng H , Chen J , Zhang Z . (2017). MoS₂ quantum dots-interspersed Bi₂WO₆ heterostructures for visible light-induced detoxification and disinfection. Applied Catalysis B: Environmental, 210: 160–172

[63] Monisha R S , Mani R L , Sivaprakash B , Rajamohan N , Vo D V N . (2022). Green remediation of pharmaceutical wastes using biochar: a review. Environmental Chemistry Letters, 20(1): 681–704

[64] Monticelli S , Talbot A , Gotico P , Caillé F , Loreau O , Del Vecchio A , Malandain A , Sallustrau A , Leibl W , Aukauloo A . . (2023). Unlocking full and fast conversion in photocatalytic carbon dioxide reduction for applications in radio-carbonylation. Nature Communications, 14(1): 4451

[65] Murugan C , Ranjithkumar K , Pandikumar A . (2021). Interfacial charge dynamics in type-II heterostructured sulfur doped-graphitic carbon nitride/bismuth tungstate as competent photoelectrocatalytic water splitting photoanode. Journal of Colloid and Interface Science, 602: 437–451

[66] Ng B J , Putri L K , Kong X Y , Teh Y W , Pasbakhsh P , Chai S P . (2020). Z-scheme photocatalytic systems for solar water splitting. Advanced Science, 7(7): 1903171

[67] Ning J , Zhang J , Dai R , Wu Q , Zhang L , Zhang W , Yan J , Zhang F . (2022). Experiment and DFT study on the photocatalytic properties of La-doped Bi₂WO₆ nanoplate-like materials. Applied Surface Science, 579: 152219

[68] Orimolade B O , Idris A O , Feleni U , Mamba B . (2021). Recent advances in degradation of pharmaceuticals using Bi₂WO₆ mediated photocatalysis: a comprehensive review. Environmental Pollution, 289: 117891

[69] Osman A I , Fawzy S , Farghali M , El-Azazy M , Elgarahy A M , Fahim R A , Maksoud M I A A , Ajlan A A , Yousry M , Saleem Y . . (2022). Biochar for agronomy, animal farming, anaerobic digestion, composting, water treatment, soil remediation, construction, energy storage, and carbon sequestration: a review. Environmental Chemistry Letters, 20(4): 2385–2485

[70] Peng D Y , Zeng H Y , Xiong J , Liu F Y , Wang L H , Xu S , Yang Z L , Liu S G . (2023). Tuning oxygen vacancy in Bi₂WO₆ by heteroatom doping for enhanced photooxidation-reduction properties. Journal of Colloid and Interface Science, 629: 133–146

[71] Phu N D , Hoang L H , Chen X B , Kong M H , Wen H C , Chou W C . (2015). Study of photocatalytic activities of Bi₂WO₆ nanoparticles synthesized by fast microwave-assisted method. Journal of Alloys and Compounds, 647: 123–128

[72] Phu N D , Hoang L H , Van Hai P , Huy T Q , Chen X B , Chou W C . (2020). Photocatalytic activity enhancement of Bi₂WO₆ nanoparticles by Ag doping and Ag nanoparticles modification. Journal of Alloys and Compounds, 824: 153914

[73] Qian X , Yue D , Tian Z , Reng M , Zhu Y , Kan M , Zhang T , Zhao Y . (2016). Carbon quantum dots decorated Bi₂WO₆ nanocomposite with enhanced photocatalytic oxidation activity for VOCs. Applied Catalysis B: Environmental, 193: 16–21

[74] Rajaji U , Govindasamy M , Chen S M , Chen T W , Liu X , Chinnapaiyan S . (2018). Microwave-assisted synthesis of Bi₂WO₆ flowers decorated graphene nanoribbon composite for electrocatalytic sensing of hazardous dihydroxybenzene isomers. Composites. Part B, Engineering, 152: 220–230

[75] Ren H , Qi F , Labidi A , Zhao J , Wang H , Xin Y , Luo J , Wang C . (2023). Chemically bonded carbon quantum dots/Bi₂WO₆ S-scheme heterojunction for boosted photocatalytic antibiotic degradation: Interfacial engineering and mechanism insight. Applied Catalysis B: Environmental, 330: 122587

[76] Shang Z , Feng X , Chen G , Qin R , Han Y . (2023). Recent advances on single-atom catalysts for photocatalytic CO₂ reduction. Small, 19(48): 2304975

[77] Shi Y , Zhao Z , Yang D , Tan J , Xin X , Liu Y , Jiang Z . (2023). Engineering photocatalytic ammonia synthesis. Chemical Society Reviews, 52(20): 6938–6956

[78] Song N , Zhang S , Zhong S , Su X , Ma C . (2022). A direct Z-scheme polypyrrole/Bi₂WO₆ nanoparticles with boosted photogenerated charge separation for photocatalytic reduction of Cr(VI): characteristics, performance, and mechanisms. Journal of Cleaner Production, 337: 130577

[79] Song J , Li C , Wang X , Zhi S , Wang X , Sun J . (2021). Visible-light-driven heterostructured g-C₃N₄/Bi-TiO₂ floating photocatalyst with enhanced charge carrier separation for photocatalytic inactivation of Microcystis aeruginosa. Frontiers of Environmental Science & Engineering, 15(6): 129

[80] Tao R , Li X , Li X , Liu S , Shao C , Liu Y . (2020). Discrete heterojunction nanofibers of BiFeO₃/Bi₂WO₆: novel architecture for effective charge separation and enhanced photocatalytic performance. Journal of Colloid and Interface Science, 572: 257–268

[81] Torres‐Pinto A , Silva C G , Faria J L , Silva A M T . (2021). Advances on graphyne-family members for superior photocatalytic behavior. Advanced Science, 8(10): 2003900

[82] Verma A , Dhanaraman E , Chen W T , Fu Y P . (2023). Optimization of intercalated 2D BiOCl sheets into Bi₂WO₆ flowers for photocatalytic NH₃ production and antibiotic pollutant degradation. ACS Applied Materials & Interfaces, 15(31): 37540–37553

[83] Wang J , Tang L , Zeng G , Deng Y , Dong H , Liu Y , Wang L , Peng B , Zhang C , Chen F . (2018a). 0D/2D interface engineering of carbon quantum dots modified Bi₂WO₆ ultrathin nanosheets with enhanced photoactivity for full spectrum light utilization and mechanism insight. Applied Catalysis B: Environmental, 222: 115–123

[84] Wang J , Zhi D , Zhou H , He X , Zhang D . (2018b). Evaluating tetracycline degradation pathway and intermediate toxicity during the electrochemical oxidation over a Ti/Ti₄O₇ anode. Water Research, 137: 324–334

[85] Wang L , Wang Z , Zhang L , Hu C . (2018c). Enhanced photoactivity of Bi₂WO₆ by iodide insertion into the interlayer for water purification under visible light. Chemical Engineering Journal, 352: 664–672

[86] Wang M , Zeng S , Woldu A R , Hu L . (2022). BiVO₄/Bi₂S₃ Z-scheme heterojunction with MnO_x as a cocatalyst for efficient photocatalytic CO₂ conversion to methanol by pure water. Nano Energy, 104: 107925

[87] Wang S , Xiong Z , Yang N , Ding X , Chen H . (2020a). Iodine-doping-assisted tunable introduction of oxygen vacancies on bismuth tungstate photocatalysts for highly efficient molecular oxygen activation and pentachlorophenol mineralization. Chinese Journal of Catalysis, 41(10): 1544–1553

[88] Wang T , Bai Y , Si W , Mao W , Gao Y , Liu S . (2021a). Heterogeneous photo-Fenton system of novel ternary Bi₂WO₆/BiFeO₃/g-C₃N₄ heterojunctions for highly efficient degrading persistent organic pollutants in wastewater. Journal of Photochemistry and Photobiology A Chemistry, 404: 112856

[89] Wang T , Feng C , Liu J , Wang D , Hu H , Hu J , Chen Z , Xue G . (2021b). Bi₂WO₆ hollow microspheres with high specific surface area and oxygen vacancies for efficient photocatalysis N₂ fixation. Chemical Engineering Journal, 414: 128827

[90] Wang T , Liu S , Mao W , Bai Y , Chiang K , Shah K , Paz-Ferreiro J . (2020b). Novel Bi₂WO₆ loaded N-biochar composites with enhanced photocatalytic degradation of Rhodamine B and Cr(VI). Journal of Hazardous Materials, 389: 121827

[91] Wang T , Mao W , Wu Y , Bai Y , Gao Y , Liu S , Wu H . (2019). Heterogeneous photo-Fenton degradation of Rhodamine B dye via a high visible-light responsive Bi₂WO₆ and BiFeO₃ heterojunction composites. Journal of Materials Science Materials in Electronics, 30(17): 16452–16462

[92] Wang T , Xiao G , Li C , Zhong S , Zhang F . (2015). One-step synthesis of a sulfur doped Bi₂WO₆/Bi₂O₃ composite with enhanced visible-light photocatalytic activity. Materials Letters, 138: 81–84

[93] Wang Y , Dai Z , Wang J , Zhang D , Zhou F , Li J , Huang J . (2023a). Scheme-II heterojunction of Bi₂WO₆@Br-COFs hybrid materials for CO₂ photocatalytic reduction. Chemical Engineering Journal, 471: 144559

[94] Wang Y , Hu J , Ge T , Chen F , Lu Y , Chen R , Zhang H , Ye B , Wang S , Zhang Y . . (2023b). Gradient cationic vacancies enabling inner-to-outer tandem homojunctions: strong local internal electric field and reformed basic sites boosting CO₂ photoreduction. Advanced Materials, 35(31): 2302538

[95] Wei J , Xia Y , Qayum A , Jiao X , Chen D , Wang T . (2020). Unexpected photoinduced room temperature magnetization in Bi₂WO₆ nanosheets. Small, 16(50): 2005704

[96] Wu J , Huang Y , Ye W , Li Y . (2017). CO₂ reduction: from the electrochemical to photochemical approach. Advanced Science, 4(11): 1700194

[97] Wu S , Sun J , Li Q , Hood Z D , Yang S , Su T , Peng R , Wu Z , Sun W , Kent P R C . . (2020). Effects of surface terminations of 2D Bi₂WO₆ on photocatalytic hydrogen evolution from water splitting. ACS Applied Materials & Interfaces, 12(17): 20067–20074

[98] Xiang Y , Ju P , Wang Y , Sun Y , Zhang D , Yu J . (2016). Chemical etching preparation of the Bi₂WO₆/BiOI p-n heterojunction with enhanced photocatalytic antifouling activity under visible light irradiation. Chemical Engineering Journal, 288: 264–275

[99] Xing Z , Hu J , Ma M , Lin H , An Y , Liu Z , Zhang Y , Li J , Yang S . (2019). From one to two: in situ construction of an ultrathin 2D–2D closely bonded heterojunction from a single-phase monolayer nanosheet. Journal of the American Chemical Society, 141(50): 19715–19727

[100] Xu S , Zhang Y J , Tang R , Zhang X , Hu Z H , Yu H Q . (2021). Enhancing Fenton-like catalytic efficiency of Bi₂WO₆ by iodine doping for pollutant degradation. Separation and Purification Technology, 277: 119447

[101] Xu X , Ge Y , Li B , Fan F , Wang F . (2014). Shape evolution of Eu-doped Bi₂WO₆ and their photocatalytic properties. Materials Research Bulletin, 59: 329–336

[102] Xue X , Chen X , Zhang Z , Fan G , Ma T . (2023). Improved ionic organic pollutant degradation under visible light by Ag SPR-promoted phosphorus-doped g-C₃N₄/AgBr/Bi₂WO₆ with excellent charge transfer capacity and high surface area. Journal of Alloys and Compounds, 930: 167457

[103] Yan T , Yang Q , Feng R , Ren X , Zhao Y , Sun M , Yan L , Wei Q . (2022). Highly effective visible-photocatalytic hydrogen evolution and simultaneous organic pollutant degradation over an urchin-like oxygen-doped MoS₂/ZnIn₂S₄ composite. Frontiers of Environmental Science & Engineering, 16(10): 131

[104] Yang C , Zhang Z , Wang P , Xu P , Shen T , Wang M , Zheng Q , Zhang G . (2023a). Ultrathin g-C₃N₄ composite Bi₂WO₆ embedded in PVDF UF membrane with enhanced permeability, anti-fouling performance and durability for efficient removal of atrazine. Journal of Hazardous Materials, 451: 131154

[105] Yang J , Wang L , Yang J , Li C , Zhong S . (2023b). Magnetic biochar coupled with bismuth tungstate for multiple antibiotic removal from contaminated water: characteristics, performance, and competitive adsorption synergistic photocatalysis mechanism. Journal of Environmental Chemical Engineering, 12(1): 111768

[106] Yang M , Xu T , Jin X , Shen Q , Sun C . (2022). Oxygen vacancies enriched Bi₂WO₆ for enhanced decabromodiphenyl ether photodegradation via C-Br bond activation. Applied Surface Science, 581(15): 152439

[107] Yang X , Ma Y , Liu Y , Wang K , Wang Y , Liu M , Qiu X , Li W , Li J . (2021). Defect-induced Ce-doped Bi₂WO₆ for efficient electrocatalytic N₂ reduction. ACS Applied Materials & Interfaces, 13(17): 19864–19872

[108] Ye K , Li Y , Yang H , Li M , Huang Y , Zhang S , Ji H . (2019). An ultrathin carbon layer activated CeO₂ heterojunction nanorods for photocatalytic degradation of organic pollutants. Applied Catalysis B: Environmental, 259: 118085

[109] Yi H , Qin L , Huang D , Zeng G , Lai C , Liu X , Li B , Wang H , Zhou C , Huang F . . (2019). Nano-structured bismuth tungstate with controlled morphology: fabrication, modification, environmental application and mechanism insight. Chemical Engineering Journal, 358: 480–496

[110] Yuan T , Li Z , Zhang W , Xue Z , Wang X , Ma Z , Fan Y , Xu J , Wu Y . (2019). Highly sensitive ethanol gas sensor based on ultrathin nanosheets assembled Bi₂WO₆ with composite phase. Science Bulletin, 64(9): 595–602

[111] Zeng Y , Yin Q , Liu Z , Dong H . (2022). Attapulgite-interpenetrated g-C₃N₄/Bi₂WO₆ quantum-dots Z-scheme heterojunction for 2-mercaptobenzothiazole degradation with mechanism insight. Chemical Engineering Journal, 435: 134918

[112] Zhang C , Ren J , Hua J , Xia L , He J , Huo D , Hu Y . (2018a). Multifunctional Bi₂WO₆ nanoparticles for CT-guided photothermal and oxygen-free photodynamic therapy. ACS Applied Materials & Interfaces, 10(1): 1132–1146

[113] Zhang C , Xia D , Liu J , Huo D , Jiang X , Hu Y . (2020a). Bypassing the immunosuppression of myeloid-derived suppressor cells by reversing tumor hypoxia using a platelet-inspired platform. Advanced Functional Materials, 30(22): 2000189

[114] Zhang J , Yuan X , Jiang L , Wu Z , Chen X , Wang H , Wang H , Zeng G . (2018b). Highly efficient photocatalysis toward tetracycline of nitrogen doped carbon quantum dots sensitized bismuth tungstate based on interfacial charge transfer. Journal of Colloid and Interface Science, 511: 296–306

[115] Zhang L , He F , Mao W , Guan Y . (2020b). Fast and efficient removal of Cr(VI) to ppb level together with Cr(III) sequestration in water using layered double hydroxide interclated with diethyldithiocarbamate. Science of the Total Environment, 727: 138701

[116] Zhang L , Yang C , Lv K , Lu Y , Li Q , Wu X , Li Y , Li X , Fan J , Li M . (2019). SPR effect of bismuth enhanced visible photoreactivity of Bi₂WO₆ for NO abatement. Chinese Journal of Catalysis, 40(5): 755–764

[117] Zhang M , Mao Y , Bao X , Zhai G , Xiao D , Liu D , Wang P , Cheng H , Liu Y , Zheng Z . . (2023). Coupling benzylamine oxidation with CO₂ photoconversion to ethanol over a black phosphorus and bismuth tungstate S-scheme heterojunction. Angewandte Chemie International Edition, 62(36): e202302919

[118] Zhang X , Han F , Shi B , Farsinezhad S , Dechaine G P , Shankar K . (2012). Photocatalytic conversion of diluted CO₂ into light hydrocarbons using periodically modulated multiwalled nanotube arrays. Angewandte Chemie International Edition, 51(51): 12732–12735

[119] Zhang Y , Li Y , Yuan Y . (2022). Carbon quantum dot-decorated BiOBr/Bi₂WO₆ photocatalytic micromotor for environmental remediation and DFT calculation. ACS Catalysis, 12(22): 13897–13909

[120] Zhang Z , Wang W , Gao E , Shang M , Xu J . (2011). Enhanced photocatalytic activity of Bi₂WO₆ with oxygen vacancies by zirconium doping. Journal of Hazardous Materials, 196: 255–262

[121] Zhao S , Chen C , Ding J , Yang S , Zang Y , Ren N . (2022). One-pot hydrothermal fabrication of BiVO₄/Fe₃O₄/rGO composite photocatalyst for the simulated solar light-driven degradation of Rhodamine B. Frontiers of Environmental Science & Engineering, 16(3): 36

[122] Zhao L , Hou H , Wang L , Bowen C R , Wang J , Yan R , Zhan X , Yang H , Yang M , Yang W . (2024a). Atomic-level surface modification of ultrathin Bi₂WO₆ nanosheets for boosting photocatalytic CO₂ reduction. Chemical Engineering Journal, 480: 148033

[123] Zhao L , Wang J , Yang W , Hou H , Yan R . (2023). Efficient photoreduction of carbon dioxide into carbon-based fuels: a review. Environmental Chemistry Letters, 21(3): 1499–1513

[124] Zhao Y , Fan X , Zheng H , Liu E , Fan J , Wang X . (2024b). Bi₂WO₆/AgInS₂ S-scheme heterojunction: efficient photodegradation of organic pollutant and toxicity evaluation. Journal of Materials Science and Technology, 170: 200–211

[125] Zhao Y , Liang X , Wang Y , Shi H , Liu E , Fan J , Hu X . (2018a). Degradation and removal of Ceftriaxone sodium in aquatic environment with Bi₂WO₆/g-C₃N₄ photocatalyst. Journal of Colloid and Interface Science, 523: 7–17

[126] Zhao Y , Wang Y , Liu E , Fan J , Hu X . (2018b). Bi₂WO₆ nanoflowers: an efficient visible light photocatalytic activity for ceftriaxone sodium degradation. Applied Surface Science, 436: 854–864

[127] Zheng X , Han T , Shi H . (2023). Cu-doped Bi₂WO_6–x photocatalyst with efficient charge separation ability for enhanced peroxymonosulfate activation. Journal of Molecular Liquids, 391: 123273

[128] Zhou F , Zhu Y . (2012). Significant photocatalytic enhancement in methylene blue degradation of Bi₂WO₆ photocatalysts via graphene hybridization. Journal of Advanced Ceramics, 1(1): 72–78

[129] Zhou Y , Zhang Y , Lin M , Long J , Zhang Z , Lin H , Wu J C S , Wang X . (2015). Monolayered Bi₂WO₆ nanosheets mimicking heterojunction interface with open surfaces for photocatalysis. Nature Communications, 6(1): 8340

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 52300209); the Guangdong Higher Education Institutions Innovative Research Team of Urban Water Cycle and Ecological Safety (China) (No. 2023KCXTD053); and the Shenzhen Science and Technology Innovation Commission (China) (Nos. WDZC20200821090937001 and KCXST20221021111401004); and the Scientific Research Start-up Funds from Tsinghua Shenzhen International Graduate School (China) (No. QD2023020C).

Conflict of Interests

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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