Developing low-cost and efficient catalysts for oxygen evolution reactions (OER) with both excellent activity and robust stability remains a great challenge. Herein, we report a facile spontaneous redox reaction to grow cobalt-doped MnO₂ ultrathin nanosheets in situ with abundant oxygen vacancies vertically aligned on cobalt/nitrogen co-functionalized carbon nanofibers (Co-MnO₂|O_V) as an efficient OER catalyst. It is confirmed that metallic cobalt plays a critical role in the formation of long and ultrathin MnO₂ nanosheets during the redox reaction. Furthermore, the cobalt ions doped into MnO₂ significantly enhance the catalytic activity of MnO₂ nanosheets. Benefiting from the collaborative advantages of doping strategy, fast charge transfer kinetics and strong synergistic coupling effects, Co-MnO₂|O_V composites exhibit an excellent catalytic activity and a good durability for electrochemical water oxidation, reaching 10 mA cm⁻² at an overpotential of 279 mV. According to the density functional theory (DFT) calculations, the enhanced catalytic activity mainly originates from a better conductivity and the decreased adsorption energy barrier of OH^- on the O sites neighboring the doped Co and oxygen vacancies. Our findings suggest that the control over the structure and composition of the materials can achieve highly efficient oxygen evolution electrocatalysts.

开发既具有出色活性又具有稳定稳定性的低成本高效的氧气析出反应（OER）催化剂仍然是一个巨大的挑战。在本文中，我们报告了一种易于自发的氧化还原反应，以原位生长具有大量氧空位的钴掺杂MnO ₂超薄纳米片，该氧空位在作为有效的OER催化剂的钴/氮共官能化碳纳米纤维（Co-MnO ₂ | O _V）上垂直排列。证实了金属钴在氧化还原反应期间在长且超薄的MnO ₂纳米片的形成中起关键作用。此外，掺杂到MnO的钴离子₂显著提高的MnO的催化活性₂纳米片。受益于掺杂策略的协同优势，快速的电荷转移动力学和强大的协同耦合效应，Co-MnO ₂ | O _V复合材料表现出出色的催化活性和良好的电化学水氧化耐久性，在超电势下可达到10 mA cm ^-2 279 mV。根据密度泛函理论（DFT）计算，增强的催化活性主要由更好的导电性起源和OH的吸附能量势垒下降^-对将O站点相邻的掺杂的Co和氧空位。我们的发现表明，对材料的结构和组成的控制可以实现高效的析氧电催化剂。