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  • RESEARCH ARTICLE
    Yixuan Chang, Fanwei Kong, Zihao Zhu, Ziai Wang, Chunxia Chen, Xiaobai Li, Hongwei Ma
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 966-975. https://doi.org/10.1007/s11705-022-2244-1

    The efficient utilization of natural lignin, which is the main by-product of the cellulose industry, is crucial for enhancing its economic value, alleviating the environmental burden, and improving ecological security. By taking advantage of the large sp2 hybrid domain of lignin and introducing amino functional groups, new lignin-derived carbon dots (SPN-CDs) with red fluorescence were successfully synthesized. Compared with green and blue fluorescent materials, red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability. The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite. Considering this feature, a portable, low-cost, and sensitive fluorescence sensing paper with a low limit of detection of 0.249 μmol∙L–1 was fabricated using the SPN-CDs for hypochlorite detection. Furthermore, a new type of visible-light and fluorescence dual-channel information encryption platform was constructed. Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus, as well as an information “eraser”, facilitating a safe and diversified transmission and convenient decryption of information. This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.

  • RESEARCH ARTICLE
    Chenxi Xu, Shunli Li, Zhaohui Hou, Liming Yang, Wenbin Fu, Fujia Wang, Yafei Kuang, Haihui Zhou, Liang Chen
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 679-690. https://doi.org/10.1007/s11705-022-2266-8

    The massive conversion of resourceful biomass to carbon nanomaterials not only opens a new avenue to effective and economical disposal of biomass, but provides a possibility to produce highly valued functionalized carbon-based electrodes for energy storage and conversion systems. In this work, biomass is applied to a facile and scalable one-step pyrolysis method to prepare three-dimensional (3D) carbon nanotubes/mesoporous carbon architecture, which uses transition metal inorganic salts and melamine as initial precursors. The role of each employed component is investigated, and the electrochemical performance of the attained product is explored. Each component and precise regulation of their dosage is proven to be the key to successful conversion of biomass to the desired carbon nanomaterials. Owing to the unique 3D architecture and integration of individual merits of carbon nanotubes and mesoporous carbon, the as-synthesized carbon nanotubes/mesoporous carbon hybrid exhibits versatile application toward lithium-ion batteries and Zn-air batteries. Apparently, a significant guidance on effective conversion of biomass to functionalized carbon nanomaterials can be shown by this work.

  • RESEARCH ARTICLE
    Yanli Fang, Hui Wang, Xuyun Wang, Jianwei Ren, Rongfang Wang
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 373-386. https://doi.org/10.1007/s11705-022-2223-6

    The bind-free carbon cloth-supported electrodes hold the promises for high-performance electrochemical capacitors with high specific capacitance and good cyclic stability. Considering the close connection between their performance and the amount of carbon material loaded on the electrodes, in this work, NiCo2O4 nanowires were firstly grown on the substrate of active carbon cloth to provide the necessary surface area in the longitudinal direction. Then, the quinone-rich nitrogen-doped carbon shell structure was formed around NiCo2O4 nanowires, and the obtained composite was used as electrode for electric double layer capacitor. The results showed that the composite electrode displayed an area-specific capacitance of 1794 mF∙cm–2 at the current density of 1 mA∙cm–2. The assembled symmetric electric double layer capacitor achieved a high energy density of 6.55 mW∙h∙cm–3 at a power density of 180 mW∙cm–3. The assembled symmetric capacitor exhibited a capacitance retention of 88.96% after 10000 charge/discharge cycles at the current density of 20 mA∙cm–2. These results indicated the potentials in the preparation of the carbon electrode materials with high energy density and good cycling stability.

  • RESEARCH ARTICLE
    Yong Zheng, Mingjin Li, Yongye Wang, Niu Huang, Wei Liu, Shan Chen, Xuepeng Ni, Kunming Li, Siwei Xiong, Yi Shen, Siliang Liu, Baolong Zhou, Niaz Ali Khan, Liqun Ye, Chao Zhang, Tianxi Liu
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 525-535. https://doi.org/10.1007/s11705-022-2232-5

    Fe–Nx nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe–Nx nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe–Nx nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc–air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm–2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond.

  • RESEARCH ARTICLE
    Shangcong Zhang, Qian Liu, Xinyue Tang, Zhiming Zhou, Tieyan Fan, Yingmin You, Qingcheng Zhang, Shusheng Zhang, Jun Luo, Xijun Liu
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 726-734. https://doi.org/10.1007/s11705-022-2274-8

    Designing advanced and cost-effective electrocatalytic system for nitric oxide (NO) reduction reaction (NORR) is vital for sustainable NH3 production and NO removal, yet it is a challenging task. Herein, it is shown that phosphorus (P)-doped titania (TiO2) nanotubes can be adopted as highly efficient catalyst for NORR. The catalyst demonstrates impressive performance in ionic liquid (IL)-based electrolyte with a remarkable high Faradaic efficiency of 89% and NH3 yield rate of 425 μg·h−1·mgcat.−1, being close to the best-reported results. Noteworthy, the obtained performance metrics are significantly larger than those for N2 reduction reaction. It also shows good durability with negligible activity decay even after 10 cycles. Theoretical simulations reveal that the introduction of P dopants tunes the electronic structure of Ti active sites, thereby enhancing the NO adsorption and facilitating the desorption of *NH3. Moreover, the utilization of IL further suppresses the competitive hydrogen evolution reaction. This study highlights the advantage of the catalyst−electrolyte engineering strategy for producing NH3 at a high efficiency and rate.

  • RESEARCH ARTICLE
    Jiannan Zhu, Vladimir Mahalec, Chen Fan, Minglei Yang, Feng Qian
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 759-771. https://doi.org/10.1007/s11705-022-2269-5

    This work introduces a deep-learning network, i.e., multi-input self-organizing-map ResNet (MISR), for modeling refining units comprised of two reactors and a separation train. The model is comprised of self-organizing-map and the neural network parts. The self-organizing-map part maps the input data into multiple two-dimensional planes and sends them to the neural network part. In the neural network part, residual blocks enhance the convergence and accuracy, ensuring that the structure will not be overfitted easily. Development of the MISR model of hydrocracking unit also benefits from the utilization of prior knowledge of the importance of the input variables for predicting properties of the products. The results show that the proposed MISR structure predicts more accurately the product yields and properties than the previously introduced self-organizing-map convolutional neural network model, thus leading to more accurate optimization of the hydrocracker operation. Moreover, the MISR model has smoother error convergence than the previous model. Optimal operating conditions have been determined via multi-round-particle-swarm and differential evolution algorithms. Numerical experiments show that the MISR model is suitable for modeling nonlinear conversion units which are often encountered in refining and petrochemical plants.

  • RESEARCH ARTICLE
    Wenquan Xie, Xianhui Zhang, Dengke Xi, Rusen Zhou, Size Yang, Patrick Cullen, Renwu Zhou
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 594-605. https://doi.org/10.1007/s11705-022-2255-y

    The increasing amount of food waste from various industrial, agricultural, and household sources is an environmental burden if managed inappropriately. Numerous waste management approaches have been developed for the disposal of food waste, but still suffer from either high cost, production of toxic by-products, or secondary environmental pollutions. Herein, we report a new and sustainable plasma electrolysis biorefinery route for the rapid and efficient liquefaction of food waste. During the plasma electrolysis process, only the solvent is added to liquefy the waste, and anions in the waste can contribute to catalyzing the biowaste conversion. While liquefying the waste, the highly reactive species produced in the plasma electrolysis process can efficiently reduce the content of O, N, and Cl in the liquefied products and oxidize most of the metals into solid residues. Especially, the removal rate of Na and K elements was greater than 81%, which is significantly higher than using the traditional oil bath liquefaction, resulting in a relatively high-quality biocrude oil with a high heating value of 25.86 MJ·kg–1. Overall, this proposed strategy may provide a new sustainable and eco-friendly avenue for the power-to-chemicals valorization of food waste under benign conditions.

  • RESEARCH ARTICLE
    Qiaoyan Zhou, Huan Liu, Yipeng Wang, Kangxin Xiao, Guangyan Yang, Hong Yao
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 942-953. https://doi.org/10.1007/s11705-022-2264-x

    Volatile organic compounds have posed a serious threat to the environment and human health, which require urgent and effective removal. In recent years, the preparation of porous carbon from biomass waste for volatile organic compounds adsorption has attracted increasing attention as a very cost-effective and promising technology. In this study, porous carbon was synthesized from orange peel by urea-assisted hydrothermal carbonization and KOH activation. The role of typical components (cellulose, hemicellulose, and lignin) in pore development and volatile organic compounds adsorption was investigated. Among the three components, hemicellulose was the major contributor to high porosity and abundant micropores in porous carbon. Higher hemicellulose content led to more abundant –COOR, amine-N, and pyrrolic/pyridonic-N in the derived hydrochar, which were favorable for porosity formation during activation. In this case, the toluene adsorption capacity of the porous carbon improved from 382.8 to 485.3 mg·g–1. Unlike hemicellulose, cellulose reduced the >C=O, amine-N, and pyrrolic/pyridonic-N content of the hydrochar, which caused porosity deterioration and worse toluene adsorption performance. Lignin bestowed the hydrochar with slightly increased –COOR, pyrrolic/pyridonic-N, and graphitic-N, and reduced >C=O, resulting in comparatively poor porosity and more abundant micropores. In general, the obtained porous carbon possessed abundant micropores and high specific surface area, with the highest up to 2882 m2·g–1. This study can provide guidance for selecting suitable biomass waste to synthesize porous carbon with better porosity for efficient volatile organic compounds adsorption.

  • REVIEW ARTICLE
    Ting He, Jipeng Yan, Wenzhe Xiao, Jian Sun
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 798-816. https://doi.org/10.1007/s11705-023-2316-x

    The utilization of sustainable resources provides a path to relieving the problem of dependence on fossil resources. In this context, biomass materials have become a feasible substitute for petroleum-based materials. The development of biomass materials is booming and advanced biomass materials with various functional properties are used in many fields including medicine, electrochemistry, and environmental science. In recent years, ionic liquids have been widely used in biomass pretreatments and processing owing to their “green” characteristics and adjustable physicochemical properties. Thus, the effects of ionic liquids in biomass materials generation require further study. This review summarizes the multiple roles of ionic liquids in promoting the synthesis and application of advanced biomass materials as solvents, structural components, and modifiers. Finally, a prospective approach is proposed for producing additional higher-quality possibilities between ionic liquids and advanced biomass materials.

  • RESEARCH ARTICLE
    Ruiqi Li, Kang Li, Wei Wang, Fan Zhang, Shichao Tian, Zhongqi Ren, Zhiyong Zhou
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 749-758. https://doi.org/10.1007/s11705-022-2261-0

    Since lithium iron phosphate cathode material does not contain high-value metals other than lithium, it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of waste lithium iron phosphate cathode materials. Here, we describe a selective recovery process that can achieve economically efficient recovery and an acceptable lithium leaching yield. Adjusting the acid concentration and amount of oxidant enables selective recovery of lithium ions. Iron is retained in the leaching residue as iron phosphate, which is easy to recycle. The effects of factors such as acid concentration, acid dosage, amount of oxidant, and reaction temperature on the leaching of lithium and iron are comprehensively explored, and the mechanism of selective leaching is clarified. This process greatly reduces the cost of processing equipment and chemicals. This increases the potential industrial use of this process and enables the green and efficient recycling of waste lithium iron phosphate cathode materials in the future.

  • RESEARCH ARTICLE
    Wei Zhang, Runtang Liu, Xu Yang, Binbin Nian, Yi Hu
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 867-879. https://doi.org/10.1007/s11705-022-2277-5

    Polydopamine-functionalized nanosilica was synthesized using an inexpensive and easily obtainable raw material, mild reaction conditions, and simple operation. Subsequently, a flexible spacer arm was introduced by using dialdehyde starch as a cross-linking agent to bind with laccase. A high loading amount (77.8 mg∙g‒1) and activity retention (75.5%) could be achieved under the optimum immobilization conditions. Thermodynamic parameters showed that the immobilized laccase had a lower thermal deactivation rate constant and longer half-life. The enhancement of thermodynamic parameters indicated that the immobilized laccase had better thermal stability than free laccase. The residual activity of immobilized laccase remained at about 50.0% after 30 days, which was 4.0 times that of free laccase. Immobilized laccase demonstrated excellent removal of phenolic pollutants (2,4-dichlorophenol, bisphenol A, phenol, and 4-chlorophenol) and perfect reusability with 70% removal efficiency retention for 2,4-dichlorophenol after seven cycles. These results suggested that immobilized laccase possessed great reusability, improved thermal stability, and excellent storage stability. Organic–inorganic nanomaterials have a good application prospect for laccase immobilization, and the immobilized laccase of this work may provide a practical application for the removal of phenolic pollutants.

  • RESEARCH ARTICLE
    Yana Li, Zenghui Li, Yuwen Wang, Liangbo Sun, Houchang Pei
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 704-715. https://doi.org/10.1007/s11705-022-2270-z

    The multifunctional films was prepared by blending chitosan and nano-ZnO with purple tomato anthocyanins or black wolfberry anthocyanins. The properties of films functioned by anthocyanins source and nano-ZnO content were studied. It was found purple tomato anthocyanins showed more significant color change against pH than black wolfberry anthocyanins. The nano-ZnO were widely dispersed in matrix and enhanced the compatibility of anthocyanins with chitosan. However, the anthocyanins source influenced the properties of the films more slightly than nano-ZnO addition. The tensile strength, antioxidant and antibacterial effects of the chitosan films dramatically increased after cooperated by nano-ZnO and anthocyanins, which also enhanced with increase of nano-ZnO content, whereas the elongation at break of the composite films decreased. Especially, the anthocyanin and nano-ZnO promoted the antibacterial activity of films synergistically. Composite films made from black wolfberry anthocyanins exhibited higher mechanical performance than those made from purple tomato anthocyanins but weaker antibacterial effects. The purple tomato anthocyanins/chitosan and nano-ZnO/purple tomato anthocyanins/chitosan films effectively reflected pork spoilage, changing their colors from dark green to brown, indicating the potential for applications in active and intelligent food packaging.

  • RESEARCH ARTICLE
    Shangyuan Zhao, Fangjia Wang, Rui Zhou, Peisen Liu, Qizhong Xiong, Weifeng Zhang, Chaochun Zhang, Gang Xu, Xinxin Ye, Hongjian Gao
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 840-852. https://doi.org/10.1007/s11705-022-2253-0

    Herein, a Fe3+-loaded aminated polypropylene fiber has been reported as an efficient phosphate adsorbent. The remarkable phosphate removal ability of the fiber is due to Fe3+ immobilization, and it demonstrates a maximum adsorption capacity of 33.94 mg·P·g–1. Adsorption experiments showed that the fiber is applicable over a wide pH range from 2 to 9. Furthermore, the adsorption kinetics and isotherm data were consistent with the pseudo-second-order and Langmuir adsorption models, respectively. The adsorption equilibrium of the fiber for phosphate was reached within 60 min, indicating an efficient monolayer chemisorption process. Moreover, the adsorbent maintained prominent phosphate removal in the presence of competitive ions such as NO3 and Cl, exhibiting high selectivity. More importantly, the fiber demonstrated excellent reusability (5 times) and low adsorption limit below 0.02 mg·P·g–1. In addition, the phosphate removal efficiency of the fiber can exceed 99% under continuous flow conditions. The adsorption mechanism was studied by X-ray photoelectron spectroscopy, showing that the adsorption of phosphate on the fiber mainly depended on the chemical adsorption of the modified Fe3+. Overall, this study proves that the fiber possesses many advantages for phosphate removal, including high adsorption efficiency, lower treatment limit, good recyclability, and environmental friendliness.

  • RESEARCH ARTICLE
    Xin Chen, Liang Luo, Shihong Huang, Xingbo Ge, Xiuyun Zhao
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 570-580. https://doi.org/10.1007/s11705-022-2247-y

    Recently, metal–organic frameworks are one of the potential catalytic materials for electrocatalytic applications. The oxygen reduction reaction and oxygen evolution reaction catalytic activities of heterometallic cluster-based organic frameworks are investigated using density functional theory. Firstly, the catalytic activities of heterometallic clusters are investigated. Among all heterometallic clusters, Fe2Mn–Mn has a minimum overpotential of 0.35 V for oxygen reduction reaction, and Fe2Co–Co possesses the smallest overpotential of 0.32 V for oxygen evolution reaction, respectively 100 and 50 mV lower than those of Pt(111) and RuO2(110) catalysts. The analysis of the potential gap of Fe2M clusters indicates that Fe2Mn, Fe2Co, and Fe2Ni clusters possess good bifunctional catalytic activity. Additionally, the catalytic activity of Fe2Mn and Fe2Co connected through 3,3′,5,5′-azobenzenetetracarboxylate linker to form Fe2M–PCN–Fe2M is explored. Compared with Fe2Mn–PCN–Fe2Mn, Fe2Co–PCN–Fe2Co, and isolated Fe2M clusters, the mixed-metal Fe2Co–PCN–Fe2Mn possesses excellent bifunctional catalytic activity, and the values of potential gap on the Mn and Co sites of Fe2Co–PCN–Fe2Mn are 0.69 and 0.70 V, respectively. Furthermore, the analysis of the electron structure indicates that constructing a mixed-metal cluster can efficiently enhance the electronic properties of the catalyst. In conclusion, the mixed-metal cluster strategy provides a new approach to further design and synthesize high-efficiency bifunctional electrocatalysts.

  • RESEARCH ARTICLE
    Yi-Fan Xue, Jie Feng, Yun-Cai Song, Wen-Ying Li
    Frontiers of Chemical Science and Engineering, 2023, 17(12): 1986-2000. https://doi.org/10.1007/s11705-023-2337-5

    Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp3-hybridized C–N bond cleavage than sp2-hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.

  • RESEARCH ARTICLE
    Yongsheng Zhang, Xiaomeng Yang, Jinpan Bao, Hang Qian, Dong Sui, Jianshe Wang, Chunbao Charles Xu, Yanfang Huang
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 504-515. https://doi.org/10.1007/s11705-022-2260-1

    Phenolic resins were employed to prepare electrospun porous carbon nanofibers with a high specific surface area as free-standing electrodes for high-performance supercapacitors. However, the sustainable development of conventional phenolic resin has been challenged by petroleum-based phenol and formaldehyde. Lignin with abundant phenolic hydroxyl groups is the main non-petroleum resource that can provide renewable aromatic compounds. Hence, lignin, phenol, and furfural were used to synthesize bio-based phenolic resins, and the activated carbon nanofibers were obtained by electrospinning and one-step carbonization activation. Fourier transform infrared and differential scanning calorimetry were used to characterize the structural and thermal properties. The results reveal that the apparent activation energy of the curing reaction is 89.21 kJ·mol–1 and the reaction order is 0.78. The activated carbon nanofibers show a uniform diameter, specific surface area up to 1100 m2·g–1, and total pore volume of 0.62 cm3·g–1. The electrode demonstrates a specific capacitance of 238 F·g–1 (0.1 A·g–1) and good rate capability. The symmetric supercapacitor yields a high energy density of 26.39 W·h·kg–1 at 100 W·kg–1 and an excellent capacitance retention of 98% after 10000 cycles. These results confirm that the activated carbon nanofiber from bio-based phenolic resins can be applied as electrode material for high-performance supercapacitors.

  • RESEARCH ARTICLE
    Xiuzhi Tian, Rui Yang, Chuanyin Xiong, Haibo Deng, Yonghao Ni, Xue Jiang
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 853-866. https://doi.org/10.1007/s11705-022-2256-x

    The discharge of large amounts of dye-containing wastewater seriously threats the environment. Adsorbents have been adopted to remove these dyes present in the wastewater. However, the high adsorption capacity, predominant pH-responsibility, and excellent recyclability are three challenges to the development of efficient adsorbents. The poly(acryloxyethyl trimethylammonium chloride)-graft-dialdehyde cellulose nanocrystals were synthesized in our work. Subsequently, the cationic dialdehyde cellulose nanocrystal cross-linked chitosan nanocomposite foam was fabricated via freeze-drying of the hydrogel. Under the optimal ratio of the cationic dialdehyde cellulose nanocrystal/chitosan (w/w) of 12/100, the resultant foam (Foam-12) possesses excellent absorption properties, such as high porosity, high content of active sites, strong acid resistance, and high amorphous region. Then, Foam-12 was applied as an eco-friendly adsorbent to remove acid red 134 (a representative of anionic dyes) from aqueous solutions. The maximum dye adsorption capacity of 1238.1 mg∙g‒1 is achieved under the conditions of 20 mg∙L‒1 adsorbents, 100 mg∙L‒1 dye, pH 3.5, 24 h, and 25 °C. The dominant adsorption mechanism for the anionic dye adsorption is electrostatic attraction, and Foam-12 can effectively adsorb acid red 134 at pH 2.5–5.5 and be desorbed at pH 8. Its easy recovery and good reusability are verified by the repeated acid adsorption–alkaline desorption experiments.

  • RESEARCH ARTICLE
    Yili Liu, Guoliang Che, Weizhong Cui, Beili Pang, Qiong Sun, Liyan Yu, Lifeng Dong
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 516-524. https://doi.org/10.1007/s11705-022-2238-z

    All-inorganic cesium lead bromide (CsPbBr3) perovskite solar cells have been attracting growing interest due to superior performance stability and low cost. However, low light absorbance and large charge recombination at TiO2/CsPbBr3 interface or within CsPbBr3 film still prevent further performance improvement. Herein, we report devices with high power conversion efficiency (9.16%) by introducing graphene oxide quantum dots (GOQDs) between TiO2 and perovskite layers. The recombination of interfacial radiation can be effectively restrained due to enhanced charge transfer capability. GOQDs with C-rich active sites can involve in crystallization and fill within the CsPbBr3 perovskite film as functional semiconductor additives. This work provides a promising strategy to optimize the crystallization process and boost charge extraction at the surface/interface optoelectronic properties of perovskites for high efficient and low-cost solar cells.

  • RESEARCH ARTICLE
    Zihuan Yu, Haiqing Yan, Chaonan Wang, Zheng Wang, Huiqin Yao, Rong Liu, Cheng Li, Shulan Ma
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 437-448. https://doi.org/10.1007/s11705-022-2228-1

    High-performance and ultra-durable electrocatalysts are vital for hydrogen evolution reaction (HER) during water splitting. Herein, by one-pot solvothermal method, MoOx/Ni3S2 spheres comprising Ni3S2 nanoparticles inside and oxygen-deficient amorphous MoOx outside in situ grow on Ni foam (NF), to assembly the heterostructure composites of MoOx/Ni3S2/NF. By adjusting volume ratio of the solvents of ethanol to water, the optimized MoOx/Ni3S2/NF-11 exhibits the best HER performance, requiring an extremely low overpotential of 76 mV to achieve the current density of 10 mA∙cm‒2 (η10 = 76 mV) and an ultra-small Tafel slope of 46 mV∙dec‒1 in 0.5 mol∙L‒1 H2SO4. More importantly, the catalyst shows prominent high catalytic stability for HER (> 100 h). The acid-resistant MoOx wraps the inside Ni3S2/NF to ensure the high stability of the catalyst under acidic conditions. Density functional theory calculations confirm that the existing oxygen vacancy and MoOx/Ni3S2 heterostructure are both beneficial to the reduced Gibbs free energy of hydrogen adsorption (|∆GH*|) over Mo sites, which act as main active sites. The heterostructure effectively decreases the formation energy of O vacancy, leading to surface reconstruction of the catalyst, further improving HER performance. The MoOx/Ni3S2/NF is promising to serve as a highly effective and durable electrocatalyst toward HER.

  • RESEARCH ARTICLE
    Yitong Wang, Yue Zhang, Li Wang
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 470-482. https://doi.org/10.1007/s11705-022-2231-6

    Amino-functionalized zirconia was synthesized by the co-condensation method using zirconium butanol and 3-aminopropyltriethoxy silane for the simultaneous removal of various impurities from aqueous 30% H2O2 solution. The results of Fourier transform infrared (FTIR) and Zeta potential showed that the content of N in amino-functionalized zirconia increased with the added amount of 3-aminopropyltriethoxy silane. Accordingly, the removal efficiency of total oxidizable carbon, phosphate and metallic ions from the H2O2 solution increased. The adsorbent with an N content of 1.62% exhibited superior adsorption performance. The removal efficiency of 82.7% for total oxidizable carbon, 34.2% for phosphate, 87.1% for Fe3+, 83.2% for Al3+, 55.1% for Ca2+ and 66.6% for Mg2+, with a total adsorption capacity of 119.6 mg·g–1, could be achieved. The studies conducted using simulated solutions showed that the adsorption process of phosphate on amino-functionalized zirconia is endothermic and spontaneous, and the behaviors could be well described by the pseudo-second-order model and Langmuir model with a maximum adsorption capacity of 186.7 mg·g–1. The characterizations of the spent adsorbents by Zeta potential, FTIR and X-ray photoelectron spectroscopy revealed that the adsorption mechanism of phosphate is predominantly electrostatic attraction by the protonated functional groups and complementary ligand exchange with zirconium hydroxyl groups.

  • RESEARCH ARTICLE
    Meiyu Zheng, Zhenzhen Cui, Jing Zhang, Jing Fu, Zhiwen Wang, Tao Chen
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 425-436. https://doi.org/10.1007/s11705-022-2229-0

    Acetoin is an important platform chemical, which has a wide range of applications in many industries. Halomonas bluephagenesis, a chassis for next generation of industrial biotechnology, has advantages of fast growth and high tolerance to organic acid salts and alkaline environment. Here, α-acetolactate synthase and α-acetolactate decarboxylase from Bacillus subtilis 168 were co-expressed in H. bluephagenesis to produce acetoin from pyruvate. After reaction condition optimization and further increase of α-acetolactate decarboxylase expression, acetoin production and yield were significantly enhanced to 223.4 mmol·L–1 and 0.491 mol·mol–1 from 125.4 mmol·L–1 and 0.333 mol·mol–1, respectively. Finally, the highest titer of 974.3 mmol·L–1 (85.84 g·L–1) of acetoin was accumulated from 2143.4 mmol·L–1 (188.6 g·L–1) of pyruvic acid within 8 h in fed-batch bioconversion under optimal reaction conditions. Moreover, the reusability of the cell catalysis was also tested, and the result illustrated that the whole-cell catalysis obtained 433.3, 440.2, 379.0, 442.8 and 339.4 mmol·L–1 (38.2, 38.8, 33.4, 39.0 and 29.9 g·L–1) acetoin in five repeated cycles under the same conditions. This work therefore provided an efficient H. bluephagenesis whole-cell catalysis with a broad development prospect in biosynthesis of acetoin.

  • RESEARCH ARTICLE
    Junlei Xiao, Hua Zhang, Yifan Wang, Chunmei Zhang, Shuijian He, Shaohua Jiang
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 387-394. https://doi.org/10.1007/s11705-022-2250-3

    Porous carbons with high specific area surfaces are promising electrode materials for supercapacitors. However, their production usually involves complex, time-consuming, and corrosive processes. Hence, a straightforward and effective strategy is presented for producing highly porous carbons via a self-activation procedure utilizing zinc gluconate as the precursor. The volatile nature of zinc at high temperatures gives the carbons a large specific surface area and an abundance of mesopores, which avoids the use of additional activators and templates. Consequently, the obtained porous carbon electrode delivers a satisfactory specific capacitance and outstanding cycling durability of 90.9% after 50000 cycles at 10 A∙g–1. The symmetric supercapacitors assembled by the optimal electrodes exhibit an acceptable rate capability and a distinguished cycling stability in both aqueous and ionic liquid electrolytes. Accordingly, capacitance retention rates of 77.8% and 85.7% are achieved after 50000 cycles in aqueous alkaline electrolyte and 10000 cycles in ionic liquid electrolyte. Moreover, the symmetric supercapacitors deliver high energy/power densities of 49.8 W∙h∙kg–1/2477.8 W∙kg–1 in the Et4NBF4 electrolyte, outperforming the majority of previously reported porous carbon-based symmetric supercapacitors in ionic liquid electrolytes.

  • RESEARCH ARTICLE
    Xiao Han, Xiaoxuan Wang, Jiafang Wang, Yingjie Xie, Cuiwei Du, Chongfei Yu, Jinglan Feng, Jianhui Sun, Shuying Dong
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 449-459. https://doi.org/10.1007/s11705-022-2226-3

    Metal–organic frameworks are recognized as promising multifunctional materials, especially metal–organic framework-based photocatalysts, which are considered to be ideal photocatalytic materials. Herein, a new type of UiO-66/MoSe2 composite was prepared using the solvothermal method. The optimum composite was selected by adjusting the mass ratio of UiO-66 and MoSe2. X-ray diffraction analysis showed that the mass ratio influenced the crystal plane exposure rate of the composite, which may have affected its photocatalytic performance. The composite is composed of ultra-thin flower-like MoSe2 that wrapped around cubic UiO-66, a structure that increases the abundance of active sites for reactions and is more conducive to the separation of carriers. The photocatalytic properties of the composite were evaluated by measuring the degradation rate of Rhodamine B and the catalyst’s ability to reduce Cr(VI)-containing wastewater under visible light irradiation. Rhodamine B was decolorized completely in 120 min, and most of the Cr(VI) was reduced within 150 min. The photochemical mechanism of the complex was studied in detail. The existence of Mo6+ and oxygen vacancies, in addition to the Z-type heterojunction promote the separation of electrons and holes, which enhances the photocatalytic effect.

  • RESEARCH ARTICLE
    Junjun Cheng, Yitao Zhao, Guohao Xu, Peng Zhang, Xuedong Zhu, Fan Yang
    Frontiers of Chemical Science and Engineering, 2023, 17(4): 404-414. https://doi.org/10.1007/s11705-022-2215-6

    Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect. In this work, the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst. The equivalent of Zn/Zr = 1 displays the best catalytic performance at 425 °C and 3.0 MPa, and benzene conversion reaches 42.9% with a selectivity of 90% towards toluene and xylene. Moreover, the carbon dioxide conversion achieves 23.3% and the carbon monoxide selectivity is lower than 35%, indicating that more than 50% carbon dioxide has been effectively incorporated into the target product, which is the best result as far as we know. Combined with characterizations, it indicated that the Zn and Zr formed a solid solution under specific conditions (Zn/Zr = 1). The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies. Additionally, the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h. This work provides promising industrial applications for the upgrading of aromatics.

  • RESEARCH ARTICLE
    Junyang Xu, Guanhua Liu, Ying He, Liya Zhou, Li Ma, Yunting Liu, Xiaobing Zheng, Jing Gao, Yanjun Jiang
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 784-794. https://doi.org/10.1007/s11705-022-2278-4

    In situ encapsulation is an effective way to synthesize enzyme@metal–organic framework biocatalysts; however, it is limited by the conditions of metal–organic framework synthesis and its acid-base stability. Herein, a biocatalytic platform with improved acid-base stability was constructed via a one-pot method using bismuth-ellagic acid as the carrier. Bismuth-ellagic acid is a green phenol-based metal–organic framework whose organic precursor is extracted from natural plants. After encapsulation, the stability, especially the acid-base stability, of amyloglucosidases@bismuth-ellagic acid was enhanced, which remained stable over a wide pH range (2–12) and achieved multiple recycling. By selecting a suitable buffer, bismuth-ellagic acid can encapsulate different types of enzymes and enable interactions between the encapsulated enzymes and cofactors, as well as between multiple enzymes. The green precursor, simple and convenient preparation process provided a versatile strategy for enzymes encapsulation.

  • REVIEW ARTICLE
    Benjing Xu, Jinhang Dai, Ziting Du, Fukun Li, Huan Liu, Xingxing Gu, Xingmin Wang, Ning Li, Jun Zhao
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 817-829. https://doi.org/10.1007/s11705-022-2254-z

    Amino acids are important nitrogen-containing chemicals that have a variety of applications. Currently, fermentation is the widely employed method to produce amino acids; however, the products are mostly limited to natural amino acids in the L-configuration. Catalytic synthesis is an alternative approach for the synthesis of amino acids with different types and configurations, where the use of renewable biomass-based feedstocks is highly attractive. To date, several lignocellulose and triacylglycerol-derived intermediates, typically α-keto acids and α-hydroxyl acids, have been transformed into amino acids via the amination reaction in the presence of additional nitrogen sources (i.e., NH3·H2O). Making full use of inherent nitrogen in biomass (i.e., chitin and protein) to produce amino acids avoids the use of extra nitrogen sources and meets the requirements of green chemistry, which is attracting increasing attention. In this review, we summarize different chemical-catalytic systems for the transformation of biomass to amino acids. An outlook on the challenges and opportunities for more effective production of amino acids from biomass by catalytic methods is provided.

  • RESEARCH ARTICLE
    Shan Jiang, Jianfeng Xi, Hongqi Dai, Huining Xiao, Weibing Wu
    Frontiers of Chemical Science and Engineering, 2023, 17(7): 830-839. https://doi.org/10.1007/s11705-022-2267-7

    A multi-functional porous paper-based material was prepared from grass pulp by simple pore-forming and green cross-linking method. As a pore-forming agent, calcium citrate increased the porosity of the paper-based material from 30% to 69% while retaining the mechanical strength. The covalent cross-linking of citric acid between cellulose fibers improved both the wet strength and adsorption capacity. In addition, owing to the introduction of high-content carboxyl groups as well as the construction of hierarchical micro-nano structure, the underwater oil contact angle was up to 165°. The separation efficiency of the emulsified oil was 99.3%, and the water flux was up to 2020 L·m–2·h–1. The theoretical maximum adsorption capacities of cadmium ion, lead ion and methylene blue reached 136, 229 and 128.9 mg·g–1, respectively. The continuous purification of complex wastewater can be achieved by using paper-based materials combined with filtration technology. This work provides a simple, low cost and environmental approach for the treatment of complex wastewater containing insoluble oil, organic dyes, and heavy metal ions.

  • RESEARCH ARTICLE
    Rongqian Meng, Jianke Tang, Hong Yang, Lijun Guo, Yongbo Song, Qiaoling Li, Yulan Niu
    Frontiers of Chemical Science and Engineering, 2023, 17(6): 735-748. https://doi.org/10.1007/s11705-022-2262-z

    In this study, a simple and effective method was proposed to improve the electrocatalytic ability of overoxidized poly(3,4-ethylenedioxythiophene)-overoxidized polypyrrole composite films modified on glassy carbon electrode for rutin and luteolin determination. The composite electrode was prepared by cyclic voltammetry copolymerization with LiClO4-water as the supporting electrolyte. The peak current of rutin and luteolin on the composite electrode gradually decreased or even disappeared with the increase in the positive potential limit. After incubation in NaOH–ethanol solution with a volume ratio of 1:1, the composite electrodes prepared at positive potential limit greater than 1.5 V exhibited enhanced differential pulse voltammetry peak currents, reduced charge transfer resistance, larger effective specific surface area and higher electron transfer rate constant. The composite electrode prepared in the potential range of 0–1.7 V showed optimal electrocatalytic performance. The X-ray photoelectron spectroscopy results indicated that the content of –SO2/–SO and –C=N– groups in the composite film increased significantly after incubation. Further, the Raman spectra and Fourier transform infrared spectra revealed that the thiophene ring structure changed from benzene-type to quinone-type, and the quinone-type pyrrole ring was formed. The electrocatalytic mechanism of the composite film was proposed based on the experimental results and further verified by Density Functional Theory calculation.

  • RESEARCH ARTICLE
    Junlin Xie, Yanli Ye, Qinglei Li, Tianhong Kang, Sensheng Hou, Qiqi Jin, Feng He, De Fang
    Frontiers of Chemical Science and Engineering, 2023, 17(5): 617-633. https://doi.org/10.1007/s11705-022-2258-8

    MnOx and Sm–Mn catalysts were prepared with the coprecipitation method, and they showed excellent activities and sulfur resistances for the selective catalytic reduction of NOx by NH3 between 50 and 300 °C in the presence of excess oxygen. 0.10Sm–Mn catalyst indicated better catalytic activity and sulfur resistance. Additionally, the Sm doping led to multi-aspect impacts on the phases, morphology structures, gas adsorption, reactions process, and specific surface areas. Therefore, it significantly enhances the NO conversion, N2 selectivity, and sulfur resistance. Based on various experimental characterization results, the reaction mechanism of catalysts and the effect of SO2 on the reaction process about the catalysts were extensively explored. For 0.10Sm–Mn catalyst, manganese sulfate and sulfur ammonium cannot be generated broadly under the influence of SO2 and the amount of surface adsorbed oxygen. The Bronsted acid sites strengthen significantly due to the addition of SO2, enhancing the sulfur resistance of the 0.10Sm–Mn catalyst.

  • RESEARCH ARTICLE
    Fulong Wang, Liang Sun, Ziyu Zhang, Fengkai Yang, Jinlong Yang, Weijian Liu
    Frontiers of Chemical Science and Engineering, 2023, 17(10): 1581-1592. https://doi.org/10.1007/s11705-023-2327-7

    Herein, Cu–Al bimetallic oxide was synthesized and mixed with mesoporous silica spheres via a simple hydrothermal method. The prepared sample was then analyzed and employed to activate potassium peroxydisulfate for bisphenol A removal. Based on the results of X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy, Cu–Al bimetallic oxide was determined as CuO-Al2O3, and mesoporous silica spheres were found around the these particles. At 30 min, a bisphenol A degradation level of 90% was achieved, and it remained at over 60% after five consecutive cycles, indicating the catalyst’s superior capacity and stability. In terms of removal performance, the radical pathway (including SO4•‒, OH •, and O2•‒) and singlet oxygen (1O2) played minor roles, while electron migration between bisphenol A, potassium peroxydisulfate, and the catalyst played a dominant role. The introduction of Al2O3 promoted the formation of surface oxygen vacancies, which improved ligand complex formation between potassium peroxydisulfate and the catalyst, thereby facilitating electron migration. Furthermore, mesoporous silica spheres augment not only enhanced bisphenol A adsorption but also alleviated Cu leaching. Overall, this work is expected to provide significant support for the rational development of catalysts with high catalytic activity for persulfate activation via surface electron migration.