Disperse metal atoms can boost the catalytic activities of carbon-based electrocatalysts for various important chemical reactions at the heart of clean energy conversion technologies, such as oxygen reduction reaction (ORR) or oxygen evolution reaction (OER), but there lacks fundamental understanding and design principle of the catalysts. Herein, we design new disperse metal atom catalysts with single-, dual-, and tri-metal sites coordinated by nitrogen and study their catalytic activities by using the density functional theory methods. The electronic structures, reaction free energies, reaction pathways, and overpotentials were calculated to predict the catalytic activities for OER and ORR. The results show that introducing heterogeneous metal sites can break the scaling factor, significantly enhancing the bifunctional catalytic activities. An intrinsic descriptor was found to well describe the catalytic activities and provide a better understanding of the local electrical field effects on catalytic activities. Among all the catalysts studied in this work, ZnCo metal pairs show the preeminent bifunctional catalytic activities. Dual-metal catalysts generally suppress the competing two-electron-transfer reaction (formation of H₂O₂) while facilitating the four-electron-transfer ORR and perform better than single- and tri-metal ones and the best commercial noble metal catalysts (e.g., Pt and RuO₂). The predictions are consistent with the previous experimental results. This work provides a theoretical base for rational design of disperse metal atom catalysts with excellent bifunctional catalytic activities.

中文翻译：

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分散多金属原子掺杂碳作为用于氧还原和放出反应的高效双功能电催化剂：设计策略

分散的金属原子可以提高碳基电催化剂对清洁能源转换技术核心的各种重要化学反应的催化活性，例如氧还原反应（ORR）或氧释放反应（OER），但目前尚缺乏基本的了解和设计催化剂的原理。在此，我们设计了一种新的具有氮配位的单，双和三金属位点的分散金属原子催化剂，并使用密度泛函理论方法研究了它们的催化活性。计算电子结构，反应自由能，反应途径和超电势以预测OER和ORR的催化活性。结果表明，引入非均相金属位点可以破坏比例因子，从而显着增强双功能催化活性。发现一个固有的描述符可以很好地描述催化活性，并提供对电场对催化活性的影响的更好理解。在这项工作研究的所有催化剂中，ZnCo金属对显示出卓越的双功能催化活性。双金属催化剂通常会抑制竞争的两电子转移反应（氢的形成₂ O ₂），同时促进四电子转移ORR，并且其性能优于单金属和三金属催化剂以及最佳的商用贵金属催化剂（例如Pt和RuO ₂）。该预测与先前的实验结果一致。这项工作为合理设计具有优良双功能催化活性的分散金属原子催化剂提供了理论基础。