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Zinc‐air batteries (ZABs) have the advantages of high energy density and rich zinc raw materials. It is a low‐cost, green and sustainable energy storage device. At present, one of the key technologies that hinder the large‐scale application of ZABs is the design and fabrication oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) bifunctional catalysts with excellent performance, especially the non‐platinum‐based catalysts. Here N‐doped carbon‐coated Fe‐based selenium oxide catalyst Fe2O(SeO3)2/Fe3C@NC with high performance has been fabricated by a one‐step pyrolysis and then the electrochemical oxidization. The experimental results confirmed that the existence of Fe−O−Se bonds in Fe2O(SeO3)2 crystal phase of Fe2O(SeO3)2/Fe3C@NC, and the Fe−O−Se bonds could obviously enhance ORR and OER catalytic performance of Fe2O(SeO3)2/Fe3C@NC. Density functional theoretical calculations (DFT) confirmed that the Fe2O(SeO3)2 in Fe2O(SeO3)2/Fe3C@NC had a higher d‐band center of Fe atom and a lower p‐orbital coupling degree with its own lattice O atom than Fe2O3, which leads to Fe site of Fe2O(SeO3)2 being more likely to adsorb external oxygen intermediates. The Fe−O−Se bonds in Fe2O(SeO3)2 results in the modification of coordination environment of Fe atoms and optimizes the adsorption energy of Fe site for oxygen intermediates. Compared with Fe2O3/Fe3C@NC, the Fe2O(SeO3)2/Fe3C@NC showed the obvious enhancements of ORR/OER catalytic activities with a half‐wave potential of 0.91 V for ORR in 0.1 M KOH electrolyte and a low overpotential of 345 mV for OER at 10 mA cm−2 in a 1.0 M KOH electrolyte. The peak power density and specific capacity of Fe2O(SeO3)2/Fe3C@NC‐based ZABs are higher than those of Pt/C+RuO2‐ZABs. The above results demonstrate that the asymmetrical Fe−O−Se bonds in Fe2O(SeO3)2 plays a key role in improving the bifunctional catalytic activities of ORR/OER for ZABs. [ABSTRACT FROM AUTHOR]

In recent years, with the global response to the emission reduction pressure caused by climate change, global awareness of green hydrogen has progressively grown. Electrolysis of water is the only way to create green hydrogen. Among them, one of the semi-reactions of the electrolysis of water is the oxygen evolution reaction (OER). One of the bottlenecks limiting the total energy efficiency of green hydrogen production from water electrolysis is its intricate four-electron transfer process. Developing highly efficient oxygen evolution catalysts is essential to increasing the efficiency of the water electrolysis process. Therefore, researchers have been exploring high-performance OER catalysts. In recent years, heterostructured electrocatalysts have shown surprisingly good performance in OER processes due to their unique structural characteristics, including synergistic effects, strain effects, and electronic interactions. This paper reviews the reaction mechanism of the OER in various pH environments, highlights the advantages of heterostructure catalysts, and provides an overview of OER heterostructure electrocatalysts. This review focuses mainly on the overall facilitating effect of heterostructures on the OER process. The aim is to emphasize the advantages of heterostructure catalysts over one-component catalysts. The paper discusses the preparation of heterostructures and explores the relationship between their structures and electrochemical properties. By providing new insights into the interfacial chemistry of OER heterostructure electrocatalysts, this review sheds light on the future opportunities and challenges for developing OER heterostructure catalysts, both in terms of fundamental understanding and practical applications. [ABSTRACT FROM AUTHOR]

The development of science and technology, rapid population growth and increasing production demands have resulted in an increase in the emission of CO2 as a significant source of environmental pollution and the greenhouse effect, which pose a considerable threat to the development of human beings and the environment. Presently, the reduction of CO2 by electrochemical devices has become one of the most promising ways to effectively reduce the concentration of CO2 in the atmosphere. This is because the CO2 electrochemical reduction reaction (CO2RR) has numerous advantages, such as mild reaction conditions, controllable reaction products, simple experimental operation, and use of renewable raw materials. Recently, due to their advantages of high atomic utilization and simple and uniform active sites, single-atom catalysts (SACs) have shown high catalytic activity and selectivity for the CO2RR, providing a promising direction for the development of highly efficient conversion of CO2. Herein, the research progress on SACs for the CO2RR in recent years is reviewed based on three aspects, including catalytic reaction principle, catalytic reaction influencing factors and application of metal-based SACs. The effects of metal type, active site coordination structure, coordination number and coordination environment of SACs on the CO2RR are discussed in detail. Finally, the challenges and future development directions of SACs in the field of CO2RR are analyzed. [ABSTRACT FROM AUTHOR]