Preferential oxidation of CO (CO-PROX) is essential for H2 purification in proton-exchange membrane fuel cells. Understanding the intrinsic electronic structural factors that influence catalytic performance is key to rational catalyst design. Using Pt single-atom catalysts supported on Fe2O3 and Fe3O4 as model systems, this work systematically investigates the relationship between structure and performance, focusing on the strength of selective orbital coupling and CO-PROX activity. On both supports, Pt single atoms are stabilized in an embedded form by substituting lattice Fe sites (Pt1@FeOx). Furthermore, CO and H2 are preferentially activated at Pt-lattice O bridge sites, while O2 activation occurs at Pt sites. Compared to the Pt1@Fe3O4 system, the Pt1@Fe2O3 system exhibits higher theoretical activity and selectivity, with energy barriers of 0.28 eV for CO oxidation and 0.87 eV for H2 oxidation. The enhanced performance of Pt1@Fe2O3 stems from its higher lattice O redox activity and an optimal selective orbital coupling strength, measured by the descriptor Σ|Δε| (the absolute value sum of band‑center shifts for the dominant interacting orbitals). This creates a clear energetic preference for activating CO over H2. This study establishes a semiquantitative structure–activity relationship linking electronic structure, adsorption strength, and catalytic performance, providing concrete theoretical guidance for experimental design of high-performance CO-PROX catalysts.
Although iron-based polyanionic cathodes are promising for use in sodium-ion batteries because of their low cost and high structural stability, their practical application is hindered by low electronic conductivity and sluggish Na+ transport kinetics at high rates. Herein, a molybdate-induced rigid–flexible composite framework strategy is proposed to regulate the polyanionic skeleton of Na3.4Fe2.4(PO4)1.4P2O7 (NFPP)/C. A series of MoO42−-doped NFPP/C cathodes is synthesized via a high-shear mixer-assisted sol–gel method. The optimized Na3.4Fe2.4(PO4)1.3(MoO4)0.1P2O7/C cathode exhibits outstanding electrochemical performance, delivering 101.1 mAh/g after 2000 cycles at 5 C with 97.02% capacity retention and a decay rate of only 0.0015% per cycle. At 10 C, it retains 99.30% of its initial capacity after 2000 cycles. Mechanistic studies reveal that the incorporation of MoO42− enhances the local flexibility of the framework while preserving the stability of the original three-dimensional structure, thereby accelerating Na+ migration and improving electrochemical kinetics. At the same time, the composite framework features favorable pathways for electron migration, which enhance its electronic conductivity. In situ X-ray diffraction confirms the highly reversible Na+ intercalation/deintercalation behavior of the modified framework. In addition, the assembled NFPP-0.1Mo||hard carbon full cell delivers 74.1 mAh/g after 2000 cycles at 10 C, with a capacity retention of 79.42%. This work provides an effective polyanion-group engineering strategy for the design of high-rate and durable iron-based cathodes for sodium-ion batteries.
The topological nanopores of covalent organic frameworks (COFs) are promising platforms for constructing photocatalytic nanoreactors for CO2 conversion. However, simultaneously increasing electron density, promoting electron transfer, and enhancing CO2 adsorption and activation within confined nanopore spaces remain critical challenges for boosting photocatalytic performance. Herein, polyhydroxylated fullerene (C60OH) molecules were assembled within the nanopores of a two-dimensional porphyrin-based COF (pCOF) through hydrogen-bonding interactions with the hydroxyl-functionalized 2,5-dihydroxyterephthalaldehyde (DHTA) acceptor units in the pCOF, thereby constructing a C60OH@pCOF photocatalytic nanoreactor featuring DHTA–C60OH molecular heterojunctions. Under full-light irradiation, the optimized C60OH@pCOF achieves a CO production rate of 40.47 μmol/(g·h) in pure water, approximately four times higher than that of pristine pCOF, along with a CO selectivity of 99%. This remarkable enhancement is mainly attributable to the introduction of C60OH molecules into the pCOF, which facilitates the directional transfer of photogenerated electrons from the porphyrin donor to the DHTA moieties and then to the C60OH acceptor. Moreover, the abundant surface hydroxyl groups on C60OH serve as metal-free catalytic sites that effectively activate pre-accumulated CO2 within the nanopore-based reactor and promote the formation and conversion of key intermediates. This study provides new insights into the design and construction of porous crystalline framework-based photocatalytic nanoreactors.
The environmental challenges posed by the discharge of printing and dyeing wastewater urgently require effective treatment technologies. This study developed an efficient adsorbent through sodium dodecylbenzenesulfonate (SDBS) self-assembled Mg/Al-layered double hydroxides (LDHs) via a one-step hydrothermal method. When an Mg2⁺/Al3⁺/SDBS molar ratio was 3:1:1.40, and calcination was performed at 300 °C for 2 h, the adsorbent achieved a markedly high removal efficiency of 84.8% and an adsorption capacity of 63.6 mg/g, substantially outperforming the unmodified LDH (8.4% removal, 6.3 mg/g). SDBS acted as an effective structure modifier, inducing morphology regulation, a dual inversion of hydrophilicity/hydrophobicity (the contact angle of Mg/Al-LDH was measured to be 124.08°, whereas that of Mg/Al/SDBS-LDH was 0°), and surface charge reversal, which critically enhanced the adsorption of crystal violet (CV). The synergistic mechanism involved mesopore filling, electrostatic attraction, hydrogen bonding, and π–π interactions. This study demonstrates that SDBS-modified LDHs are highly promising adsorbents for advancing environmental remediation strategies.
In this study, we systematically investigated the role of configurational entropy and morphological control in enhancing the electrocatalytic performance of MXenes for the hydrogen evolution reaction (HER). We successfully synthesized a series of MAX phase precursors with increasing entropy: low-entropy (single-metal) Ti2AlC, V2AlC, Nb2AlC; a medium-entropy solid solution (Ti1/3V1/3Nb1/3)2AlC; and a high-entropy (Ti1/4V1/4Nb1/4Ta1/4)2AlC. X-ray diffraction analysis confirmed the successful formation of layered hexagonal MAX phases and their transformation into MXenes, with characteristic shifts in the (002) reflection indicating interlayer expansion. Scanning and transmission electron microscopies reveal the evolution from dense, plate-like MAX grains to exfoliated, accordion-like multilayered Ti1/2V1/2Nb1/2Ta1/2CTz MXene and sheets with few-layered morphologies, while X-ray photoelectron spectroscopy demonstrates Al removal and the presence of mixed oxidation states for Ti, V, Nb, and Ta. The electrochemical analysis of HER revealed a clear trend of improved activity with increasing entropy. Single-metal MXenes exhibited overpotentials (η@10 mA/cm2) of 231–207 mV and Tafel slopes of 163–155 mV/dec. The medium-entropy (Ti1/3V1/3Nb1/3)2CTz MXene demonstrated enhanced performance (η ≈ 140 mV, Tafel slope ≈ 134 mV/dec), which was further surpassed by the high-entropy (multilayered) M-(Ti1/4V1/4Nb1/4Ta1/4)2CTz MXene (η ≈ 97 mV, Tafel slope ≈ 115 mV/dec). Exfoliating the high-entropy MXene into few-layered F- (Ti1/4V1/4Nb1/4Ta1/4)2CTz (F-Mxene) nanosheets yielded a tremendous enhancement, achieving an exceptional overpotential of 67 mV and a Tafel slope of 69 mV/dec. Alongside this superior activity, the high-entropy F-MXenes demonstrated tremendous electrochemical stability under prolonged operation, maintaining their performance for more than 55 h of continuous use. This combination of record-low overpotential, favorable kinetics, and robust durability establishes these compositionally complex, few-layered MXenes as a promising next-generation catalyst platform, paving the way for their application in efficient and sustainable hydrogen production systems.
ZSM-48 zeolite, which features one-dimensional ten-membered-ring straight channels, is an ideal support for hydroisomerization catalysts to improve fuel low-temperature fluidity. To improve the poor low-temperature fluidity of Fischer–Tropsch synthesis products, this study employed Mg modification on Pt/ZSM-48 catalysts to optimize their hydroisomerization performance. A series of Mg-Pt/ZSM-48 catalysts with varying Mg loadings was prepared via incipient wetness impregnation. The effects of Mg modification on the pore structure, acidity, and metal–acid balance of the Pt/ZSM-48 catalyst system were systematically investigated. Catalytic performance was evaluated using n-hexadecane as a model compound. The Mg species selectively modified the micropore channels, decreasing the specific surface area and micropore volume. Moreover, Mg2+ selectively neutralized Brønsted acid sites, reducing the concentration of medium-strong acid sites and Brønsted acidity while introducing Lewis acid sites, thereby lowering the Brønsted/Lewis acid ratio. Appropriate Mg modification optimized the metal–acid balance, making acid-catalyzed skeletal isomerization the rate-determining step. Although the Mg-modified catalysts exhibited moderately reduced catalytic activity, their isomer selectivity and yield were significantly enhanced. The 0.5 Mg-Pt/Z48 catalyst achieved an isomer yield of 81.81% at 91.18% conversion, representing a 9% improvement over the unmodified catalyst. The micropore confinement effect weakened the interaction between alkane molecules and micropore channels, promoting the key–lock catalytic mechanism. This increased the formation of mono-branched isomers close to the center of the main carbon chain, significantly improving the low-temperature fluidity of the fuel. This study provides a simple and efficient strategy for designing high-performance hydroisomerization catalysts for long-chain n-alkanes.
Developing high-efficiency, stable bifunctional electrocatalysts for seawater splitting is vitally essential. In this work, we fabricated an amorphous high-entropy FeCoNiMo (FCNM) phosphide bifunctional catalyst on nickel foam (NF) via facile, one-step electrodeposition at room temperature. The obtained FCNMP possessed a three-dimensional porous structure composed of ultrathin nanosheets, which is conducive to providing a large active specific surface area and promoting ion/mass transport during the reaction. The FCNMP/NF electrocatalyst exhibited outstanding electrocatalytic performance in simulated alkaline seawater, requiring the low overpotentials of 287.5 and 201.3 mV for the oxygen evolution reaction and hydrogen evolution reaction, to reach a current density of 50 mA/cm2, respectively. The enhanced catalytic performance was attributed to the synergistic effects of the optimized electronic structure of high-entropy materials, the abundant accessible active sites from the ultrathin nanosheet morphology, and the amorphous structure. Furthermore, when FCNMP/NF was used as the cathode and anode catalysts for seawater splitting, it required only 1.75 V to reach 50 mA/cm2 for overall simulated alkaline seawater splitting. The system operated stably for over 50 h, demonstrating great potential for practical applications. Moreover, the catalyst maintained a favorable electrochemical performance in real alkaline seawater. This study provides a novel strategy for the design of high-performance bifunctional electrocatalysts for alkaline seawater splitting.
Electrocatalytic CO2 reduction reaction (CO2RR) has achieved remarkable selectivity toward C1 and C2 products; however, the direct electrosynthesis of long-chain (C4+) and structurally complex molecules remains challenging. Coupling CO2 electrolysis with downstream biological, thermal, electrochemical, or organic transformations offers a practical route to produce long-chain and structurally complex compounds, thereby expanding the product spectrum to include fuels, fine chemicals, polymers, and functional materials. In this mini review, we systematically summarize recent progress in four representative cascade configurations: electro–biological, electro–thermal, electro–electro, and electro–organic systems. For each configuration, we discuss the underlying principles, analyze the key coupling challenges, and summarize the corresponding optimization strategies along with representative studies. We further compare the technological features, product scope, and scalability limitations of these cascade systems in terms of reaction condition compatibility, multiphase interface engineering, energy efficiency, and system integration. Finally, we outline future research priorities aimed at accelerating the translation of CO2 cascade technologies from laboratory-scale proof-of-concept studies to industrially relevant platforms.
Internet of Nano-Things (IoNT) drives the need for autonomous energy solutions that can operate under low‑grade, high‑entropy ambient conditions. This review examines coinage metal nanostructures—namely, Au, Ag, and Cu—as multifunctional materials for next‑generation energy‑harvesting platforms. Beyond elemental systems, selected coinage‑metal‑containing compounds are included where they play a direct mechanistic role in energy conversion. These nanostructures exhibit tunable electronic properties, high surface reactivity, and strong coupling phenomena, enabling their integration into diverse transduction mechanisms, including flexoelectric, plasmonic, piezoelectric, thermoelectric, magnetostrictive, and triboelectric systems. Strategies for performance optimization, such as surface functionalization, morphological control, and composite formation, are discussed in relation to interfacial interactions, charge transport, and structural stability. Sustainability considerations, including material availability, recyclability, and scalability, are also addressed. By synthesizing recent advances across material science, nanotechnology, and energy engineering, this review provides a forward‑looking perspective on the design of coinage-metal‑based nanogenerators for self‑powered systems in distributed IoNT environments.
Biomass valorization represents a critical frontier in green chemistry and energy chemistry, where the essence of transformation lies in the selective cleavage and reconstruction of key chemical bonds. Electrocatalysis, characterized by mild operating conditions and an environmentally benign nature, offers a highly promising and sustainable pathway for upgrading waste biomass into value-added products. From the perspective of chemical bonds, this review systematically summarizes the latest research progress in electrocatalytic biomass valorization. First, the underlying microscopic electron/proton transfer mechanisms involved in electrocatalytic oxidation and reduction are discussed. Next, the cleavage and reconstruction of key chemical bonds, including C–H, C–O, C–C, C–N, and C–S bonds, are highlighted, with an in-depth analysis of substrate activation mechanisms, reaction pathways, and corresponding catalyst design strategies. Additionally, this review analyzes the regulatory mechanisms by which the interfacial microenvironment governs the conversion selectivity of different chemical bonds. Finally, perspectives on the core challenges currently facing this field are provided, including the insufficient elucidation of dynamic reaction mechanisms, the limited development of industrial-grade and stable catalysts, and the slow progress in scaling up electrolysis devices and processes. This review aims to provide theoretical guidance and new insights for the rational design of highly selective electrocatalysts for biomass valorization.
This review summarizes key advances in electrocatalytic biomass valorization from the perspective of chemical bonds, focusing on the selective cleavage and reconstruction of C–H, C–O, C–C, C–N, and C–S bonds, substrate activation pathways, and rational catalyst design, offering theoretical guidance for designing highly selective electrocatalysts for biomass upgrading.