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Abstract Owing to their synergistic interactions, dual-atom catalysts (DACs) with well-defined active sites are attracting increasing attention. However, more experimental research and theoretical investigations are needed to further construct explicit dual-atom sites and understand the synergy that facilitates multistep catalytic reactions. Herein, we precisely design a series of asymmetric selenium-based dual-atom catalysts that comprise heteronuclear SeN2–MN2 (M = Fe, Mn, Co, Ni, Cu, Mo, etc.) active sites for the efficient oxygen reduction reaction (ORR). Spectroscopic characterisation and theoretical calculations revealed that heteronuclear selenium atoms can efficiently polarise the charge distribution of other metal atoms through short-range regulation. In addition, compared with the Se or Fe single-atom sites, the SeFe dual-atom sites facilitate a reduction in the conversion energy barrier from *O to *OH via the coadsorption of *O intermediates. Among these designed selenium-based dual-atom catalysts, selenium-iron dual-atom catalysts achieves superior alkaline ORR performance, with a half-wave potential of 0.926 V vs. a reversible hydrogen electrode. In addition, the SeN2–FeN2-based Zn–air battery has a high specific capacity (764.8 mAh g−1) and a maximum power density (287.2 mW cm−2). This work may provide a good perspective for designing heteronuclear DACs to improve ORR efficiency.

Abstract Double-atom catalysts (DACs) have opened distinctive paradigms in the field of rapidly developing atomic catalysis owing to their great potential for promoting catalytic performance in various reaction systems. However, increasing the loading and extending the service life of metal active centres represents a considerable challenge for the efficient utilization of DACs. Here, we rationally design asymmetric nitrogen, sulfur-coordinated diatomic iron centres on highly defective nitrogen-doped carbon nanosheets (denoted A-Fe2S1N5/SNC, A: asymmetric), which possess the atomic configuration of the N2S1Fe-FeN3 moiety. The abundant defects and low-electronegativity heteroatoms in the carbon-based framework endow A-Fe2S1N5/SNC with a high loading of 6.72 wt%. Furthermore, A-Fe2S1N5/SNC has a low overpotential of 193 mV for the oxygen evolution reaction (OER) at 10 mA cm−2, outperforming commercial RuO2 catalysts. In addition, A-Fe2S1N5/SNC exhibits extraordinary stability, maintaining > 97% activity for over 2000 hours during the OER process. This work provides a practical scheme for simultaneously balancing the activity and stability of DACs towards electrocatalysis applications.

Abstract The construction of sub‐nanometer cluster catalysts (