摘要 : Electrolysis of water to produce hydrogen is an efficient, clean, and environmentally friendly hydrogen production method with unlimited development prospects. However, its overall efficiency is hampered by the slow oxygen evolution reaction (OER) with complex electron transfer processes. Therefore, designing efficient and low-cost OER catalysts is the key to solving this problem. In this paper, Ir-doped Co2P/Fe2P (abbreviated as Ir-CoFeP/NF) was grown on nickel foam through the strategies of low amount noble-metal doping and mild phosphating. Phosphide derived from a floral metal–organic framework (MOF) exhibits regular three-dimensional (3D) morphology and large active area, avoiding the stacking of active sites. The addition of Ir can effectively adjust the electronic structure, change the position of the d-band center, and increase active sites, thus enhancing the catalytic activity. Hence, the optimized catalyst exhibits unexpected electrocatalytic OER activity with an ideal overpotential of 213 mV at 10 mA cm–2, as well as a low Tafel slope of 40.63 mV dec–1. Coupling with Pt/C for overall water splitting (OWS), the entire device only needs an ultralow cell voltage of 1.50 V to achieve a current density of 10 mA cm–2. Besides, the OWS can be maintained for more than 70 h. This study demonstrates the superiority of Ir-doped phosphide in accelerating water oxidation.

摘要 : Bimetallic compounds usually exhibit superior properties to monometallic compounds, owing to the synergistic effect between two components. Herein, a bimetallic boride (FeB/CoB) has been successfully fabricated by the in-situ solid state reaction. When used as electrocatalyst toward the oxygen evolution reaction (OER), the activated bimetallic boride delivers an overpotential as low as 262 mV at 10 mA cm −2 and exhibits a satisfactory stability over 60 h, surpassing the commercial RuO 2 catalyst. Theoretical calculations indicate that the high intrinsic OER activity of FeB/CoB originates from the modified electronic structure that effectively facilitates electron transfer. Therefore, this work indicates that the bimetallic borides with low cost and high performance have the potential application as anodic electrocatalysts in electrochemical water splitting.

摘要 : The sluggish triiodide reduction activity poses a significant challenge that hinders the acquisition of high efficiency in dye-sensitized solar cells (DSSCs). Herein, a one-step thermal reduction strategy is adopted to in situ construct a two-dimensional layered WS 2 /WN heterostructure and couple it onto N-doped carbon spheres (labeled as WS 2 /WN-NC). The constructed DSSC with WS 2 /WN-NC counter electrode (CE) reaches as high as power conversion efficiency (PCE) of 9.52%, surpassing that of pure Pt (8.33%). Theoretical calculations combined with X-ray photoelectron spectroscopy (XPS) analysis reveal that electrons can easily induce the transfer of electrons from WS 2 to WN and regulate the charge states of WS 2 and WN, concentrating abundant electrons at the WS 2 /WN interface, which is conducive to inhibiting the coupling of iodide ions. Electron microscopy reveals that the layered WS 2 /WN adheres to the N-doped carbon spheres, which can prevent stacking and thereby accelerate the electron transport rate. Additionally, due to the supporting role of the carbon spheres, the WS 2 /WN active substances can be fully utilized, thereby enhancing the triiodide catalytic activity. Therefore, the structure-activity relationship between the two can complement and enhance each other, thereby optimizing the DSSC reaction kinetics and enhancing the photoelectric conversion efficiency and stability.

摘要 : High energy density (HED) fuels play critical roles in modern aerospace vehicles and long-range weapon systems due to their high-quality density, high combustion calorific value and excellent propulsion capability. The HED fuels can mainly be synthesized by hydrogenation and isomerization of petroleum-based compounds, hydrodeoxygenation of biomass-derived compounds, reverse water gas shift of CO 2 and Fischer-Tropsch synthesis or hydrogenation of CO 2 and chain growth. The synthesis of HED fuels often involves multiple elementary reactions, high reaction energy barrier and formation of by-products, so developing high-performance catalysts for enhancing the reaction process are indispensable. In this review, the recent research progress of the supported metal catalysts used for synthesis of various HED fuels and the key factors affecting their catalytic efficiency are summarized. The advantages and defects of common supports such as oxides, molecular sieves, carbon materials, MOFs and their derivatives, and polymers for supporting the metals are analyzed. Special emphasis is placed on the synthesis strategy and structure–activity correlations of these catalytic materials. Finally, future challenges and opportunities for applying supported metal catalysts in HED fuels synthesis are also presented.

摘要 : Zinc-ion batteries (ZIBs) emerge as leading candidates for a flexible energy storage system, distinguished by high capacity, affordability, and inherent safety. The integration of hydrogel electrolytes, particularly those with saturated aqueous solvents, has significantly enhanced the electrochemical performance of ZIBs while preserving their essential flexibility. Nonetheless, challenges in electrochemical performance under specific conditions highlight the nascent stage of this technology, with numerous technical hurdles awaiting resolution. Addressing these challenges, recent investigations have leveraged the unique properties of cellulose hydrogel—namely, its exceptional toughness, tensile strength, extreme temperature resilience, stimulus responsiveness, and self-healing capabilities—to innovate multifunctional flexible zinc-based batteries. This paper conducts a comprehensive review of the physicochemical attributes of cellulose hydrogel electrolytes within ZIBs. We thoroughly analyze their performance under diverse environmental conditions, offering insights into the current landscape and their future potential. By examining these aspects, we aim to underscore the developmental prospects and the challenges that lie ahead for hydrogel electrolytes in ZIBs, paving the way for further advancement in this promising field.

摘要 : Cobalt-based sulfides (CSs) are generally regarded as potentially valuable anode materials for sodium-ion batteries (SIBs) due to their excellent theoretical capacity and natural abundance. Nevertheless, their slow reaction kinetics and poor structural stability restrict the practical application of the materials. In this study, the dual-carbon-confined Se–CoS2@NC@C hollow nanocubes with anion doping are synthesized using ZIF-67 as the substrate by resorcin-formaldehyde (RF) encapsulation and subsequent carbonization and sulfurization/selenization. RF- and ZIF-67-derived dual-carbon skeleton hollow structures with a robust carbon skeleton and abundant internal space minimize cyclic stress, mitigate volume changes and maintain the structural integrity of the material. More importantly, Se doping increases the lattice spacing of CoS2, weakens the strength of Co–S bonds, and modulates the electronic structure around Co atoms, thereby optimizing the adsorption energy of the material. As a result, the hollow nanocubes of Se–CoS2@NC@C demonstrates excellent electrochemical performance as the anode for SIBs, delivering a high reversible capacity of 549.4 mAh g–1 at 0.5 A g–1 after 100 cycles and a superb rate performance (541.1 mAh g–1 at 0.2 A g–1, and 393.3 mAh g–1 at 5 A g–1). This study proposes a neoteric strategy for synthesizing advanced anodes for SIBs through the synergy of anion doping engineering and dual-carbon confinement strategy.

摘要 : Proton supply is as critical as O2 activation for artificial photosynthesis of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (2e− ORR). However, proton release via water dissociation is frequently hindered because of the sluggish water oxidation reaction (WOR), extremely limiting the efficiency of photocatalytic H2O2 production. To tackle this challenge, carboxyl-enriched supramolecular polymer (perylene tetracarboxylic acid—PTCA) is elaborately prepared by molecular self-assembly for overall photosynthesis of H2O2. Interestingly, the interconversion between carboxyl as Brønsted acid and its conjugated base realizes rapid proton circulation. Through this efficient tandem proton transfer process, the spatial effect of photocatalytic reduction and oxidation reaction is greatly enhanced with reduced reaction barrier. This significantly facilitates 2e− photocatalytic ORR to synthesize H2O2 and in the meanwhile promotes 4e− photocatalytic WOR to evolve O2. Consequently, the as-developed PTCA exhibits a remarkable H2O2 yield of 185.6 μM h−1 in pure water and air atmosphere under visible light illumination. More impressively, an appreciable H2O2 yield of 78.6 μM h−1 can be well maintained in an anaerobic system owing to in situ O2 generation by 4e− photocatalytic WOR. Our study presents a novel concept for artificial photosynthesis of H2O2 via constructing efficient proton transfer pathway to enable rapid proton circulation.

摘要 : Enhancing the quality of perovskite layer and refining the interface between the perovskite layer and the hole transport layer (HTL) represent pivotal strategies for optimizing the efficiency and stability of perovskite solar cells (PSCs). We accomplished this by employing a solution isopropanol (IPA), capable of selectively dissolving residual unreacted methylammonium and formamidine salts on the perovskite surface while preserving the integrity of lead iodide. Through control of the immersion time, we facilitated secondary crystal growth on the top of perovskite film. The resultant treated film exhibited a markedly suitable bandgap position and a diminished presence of residual trips. The IPA-treated sample led to a noteworthy photovoltaic conversion efficiency (PCE) of 23.34 %, compared to 21.46 % efficiency for untreated control sample. Furthermore, under sustained illumination at AM 1.5G with 25 % relative humidity, the uncovered IPA-treated sample retained an impressive 92 % of their initial efficiency after 1000 h. Further scrutiny revealed that this solution-based treatment effectively passivated trips, enhanced perovskite film quality, established novel built-in electric fields, and mitigated charge carrier recombination. This work provides a simple perovskite film treatment approach that does not require complex molecular engineering and can be applied not only to PSCs but also to other perovskite optoelectronic devices.

摘要 : Designing low-energy consumption, highly sensitive, and stable room temperature (RT) gas sensors based on green and renewable materials is both significant and attractive. Cellulose nanocrystals (CNC), eco-friendly materials extracted from the most abundant natural polymer, cellulose, possess unique characteristics, including one-dimensional nanorod structures, abundant functional groups, large specific surface area, a high aspect ratio, and a point-to-point conductive network structure. These characteristics have shown great potential in the development of high-performance gas sensors. Herein, a magnificent C–Cu2O/CuO nanocomposite is facilely synthesized from a CNC/Cu2+ aerogel freeze-drying method followed by subsequent heat treatment. By adjusting the degree of annealing, the material forms a heterogeneous structure that is conducive to enhancing its sensing properties. Structural characterization confirms that the heterostructured Cu2O/CuO hollow nanospheres are formed and embedded within the CNC-derived carbon, providing abundant active sites for gas molecule adsorption, thereby ensuring high performance. The as-prepared sensor exhibits high sensitivity (∼1801 toward 10 ppm), excellent linearity, and selectivity to NO2 at 25 °C. Intriguingly, the calculated limit of detection (LOD) of the sensor, which integrates the merits of CNC and heterostructured Cu2O/CuO, is as low as 0.15 ppb. Therefore, it is believed that the proposed idea of constructing nanostructures provides a universal strategy for developing other types of carbon-supported porous metal oxide nanocomposites.