摘要：The rational design and construction of hierarchically porous nanostructure for oxygen reduction reaction (ORR) electrocatalysts is crucial to facilitate the exposure of accessible active sites and promote the mass/electron transfer under the gas-solid-liquid triple-phase condition. Herein, an ingenious method through the pyrolysis of creative polyvinylimidazole coordination with Zn/Fe salt precursors is developed to fabricate hierarchically porous Fe-N-doped carbon framework as efficient ORR electrocatalyst. The volatilization of Zn species combined with the nanoscale Kirkendall effect of Fe dopants during the pyrolysis build the hierarchical micro-, meso-, and macroporous nanostructure with a high specific surface area (1,586 m^(2)·g^(−1)), which provide sufficient exposed active sites and multiscale mass/charge transport channels. The optimized electrocatalyst exhibits superior ORR activity and robust stability in both alkaline and acidic electrolytes. The Zn-air battery fabricated by such attractive electrocatalyst as air cathode displays a higher peak power density than that of Pt/C-based Zn-air battery, suggesting the great potential of this electrocatalyst for Zn-air batteries.

摘要：The shortage of fossil fuels and the disastrous pollution of the environment have led to an increasing interest in artificial photosynthesis. The photocatalytic conversion of CO2 into solar fuel is believed to be one of the best methods to overcome both the energy crisis and environmental problems. It is of significant importance to efficiently manage the surface reactions and the photo-generated charge carriers to maximize the activity and selectivity of semiconductor photocatalysts for photoconversion of CO2 and H2 O to solar fuel. To date, a variety of strategies have been developed to boost their photocatalytic activity and selectivity for CO2 photoreduction. Based on the analysis of limited factors in improving the photocatalytic efficiency and selectivity, this review attempts to summarize these strategies and their corresponding design principles, including increased visible-light excitation, promoted charge transfer and separation, enhanced adsorption and activation of CO2, accelerated CO2 reduction kinetics and suppressed undesirable reaction. Furthermore, we not only provide a summary of the recent progress in the rational design and fabrication of highly active and selective photocatalysts for the photoreduction of CO2, but also offer some fundamental insights into designing highly efficient photocatalysts for water splitting or pollutant degradation.

摘要：Under the background of increasing energy crisis and global warming,semiconductor-based photocatalysis has received tremendous attention due to its potential application in green energy production,CO_(2) reduction and pollutant *** photocatalytic activity of semiconductors,however,remains low due to issues like fast recombination of photo-generated electron-hole pairs,limited electron mobility,restricted optical absorption or insufficient active *** appropriate heterojunctions is proved to be a promising method to address most of these issues and thus to improve the photocatalytic *** this review,the working mechanism of various heterojunctions is presented *** most recent advances of strategies in designing and preparing efficient heterojunction photocatalysts are further summarized and some perspectives on the future directions in this field are provided.

摘要：Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite *** this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination *** as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous *** significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme ***,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 *** built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar ***,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox *** results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction *** work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.