Single-atom catalysis (SAC) attracts wide interest for zinc–air batteries that require high-performance bifunctional electrocatalysts for oxygen reactions. However, catalyst design is still highly challenging because of the insufficient driving force for promoting multiple-electron transfer kinetics. Herein, we report a superstructure-assisted SAC on tungsten carbides for oxygen evolution and reduction reactions. In addition to the usual single atomic sites, strikingly, we reveal the presence of highly ordered Co superstructures in the interfacial region with tungsten carbides that induce internal strain and promote bifunctional catalysis. Theoretical calculations show that the combined effects from superstructures and single atoms strongly reduce the adsorption energy of intermediates and overpotential of both oxygen reactions. The catalyst therefore presented impressive bifunctional activity with an ultralow potential gap of 0.623 V and delivered a high power density of 188.5 mW cm^–2 for assembled zinc–air batteries. This work opens up new opportunities for atomic catalysis.

中文翻译：

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超结构辅助碳化钨单原子催化双功能氧反应

单原子催化（SAC）引起了锌空气电池的广泛关注，锌空气电池需要高性能双功能电催化剂来进行氧反应。然而，由于促进多电子转移动力学的驱动力不足，催化剂设计仍然具有很大的挑战性。在此，我们报告了一种基于碳化钨的超结构辅助 SAC，用于析氧和还原反应。除了常见的单原子位点之外，引人注目的是，我们揭示了在与碳化钨的界面区域中存在高度有序的Co超结构，这些超结构会引起内部应变并促进双功能催化。理论计算表明，超结构和单个原子的综合作用大大降低了中间体的吸附能和两个氧反应的超电势。因此，该催化剂呈现出令人印象深刻的双功能活性，具有 0.623 V 的超低电位间隙，并为组装的锌空气电池提供 188.5 mW cm ^–2的高功率密度。这项工作为原子催化开辟了新的机遇。