Oxygen vacancy engineering has been one of the most powerful strategies to enhance the efficiency of oxygen evolution reaction [OER]. Even though the positive effects of surface oxygen vacancy have been well proved, very controversial conclusions are also reported in perovskites. In this work, the roles of oxygen vacancies on the surface and in the bulk of La_0.7Sr_1.3Co₂O_6-δ (LSCO) are well separately investigated by X-ray absorption spectroscopy (surface sensitive) and magnetization measurement (bulk sensitive). The results suggest that massive surface oxygen vacancies have positive effects by enhancing the adsorption, while excessive oxygen vacancies in bulk is double-edged because of the interruptions of exchange interaction of cations with different valence states (Co–O–Co) and smooth transport of electrons. The sample prepared with massive surface oxygen vacancies while with less bulk oxygen vacancies yields 10 times higher specific activity at 1.6 V than commercial IrO₂. This work uncovers the role of bulk oxygen vacancies in OER process and paves the way for smart oxygen vacancy engineering for higher OER efficiency.

氧空位工程一直是增强氧释放反应[OER]效率的最有效策略之一。尽管表面氧空位的积极作用已得到充分证明，但钙钛矿中也有非常有争议的结论。在这项工作中，氧空位在La _0.7 Sr _1.3 Co ₂ O6 _-δ表面和整体中的作用（LSCO）分别通过X射线吸收光谱法（表面敏感）和磁化测量（体感敏感）分别进行了研究。结果表明，大量的表面氧空位可通过增强吸附而发挥积极作用，而散装的过量氧空位则由于具有不同价态（Co-O-Co）的阳离子交换相互作用的中断和顺畅的传输而被双重边缘化。电子。具有大量表面氧空位而体积氧空位较少的样品在1.6 V电压下的比活度是商业IrO _2的10倍。这项工作揭示了大量氧气空缺在OER过程中的作用，并为智能氧气空缺工程提高OER效率铺平了道路。