Elucidation of the relationship among crystal structure, material compositions, and electrocatalytic performance is beneficial to the design of electrocatalysts with high activity. Specially, for bifunctional electrocatalysts, there is a lack of the unified understanding of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) mechanisms. Based on the first-principles calculations, LaCoO surface reconstructions with different OH coverage under OER/ORR condition are determined. Thereby, the different reaction pathways for OER and ORR with the cooperation of Co and O sites are revealed, under which Co and lattice O sites are activated dynamically, and an overpotential of 0.35 V for the OER and 0.44 V for the ORR are obtained. Furthermore, the octahedra lattice distortion-related bifunctional mechanism (DRBM) is proposed from electron structure analysis, and the bifunctional activity of different B-site doped LaCoO (LaCoMO) are studied. Based on this mechanism, we find that OER, ORR, and their bifunctional activity of LaCoMO all exhibit a volcano trend as a function of the O-B-O bond angle formed by Co and lattice oxygen. Consequently, we predict that Mn, Cr, Fe, and Ti doped LaCoO electrocatalysts exhibit remarkable bifunctional activity, which is corroborated by the reported experimental results.

中文翻译：

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钙钛矿电催化剂表面重构诱导析氧反应和氧还原反应的双功能机制


阐明晶体结构、材料组成和电催化性能之间的关系有利于高活性电催化剂的设计。特别是，对于双功能电催化剂，对于析氧反应（OER）和氧还原反应（ORR）机制缺乏统一的认识。基于第一性原理计算，确定了OER/ORR条件下不同OH覆盖率的LaCoO表面重构。由此，揭示了Co和O位点协同作用下OER和ORR的不同反应途径，在该路径下Co和晶格O位点被动态激活，并获得了0.35 V的OER和0.44 V的ORR过电势。此外，从电子结构分析中提出了八面体晶格畸变相关的双功能机制（DRBM），并研究了不同B位掺杂的LaCoO（LaCoMO）的双功能活性。基于这一机制，我们发现LaCoMO的OER、ORR及其双功能活性都表现出火山趋势，作为Co和晶格氧形成的O-B-O键角的函数。因此，我们预测 Mn、Cr、Fe 和 Ti 掺杂的 LaCoO 电催化剂表现出显着的双功能活性，这一点已被报道的实验结果证实。