Oxygen evolution reaction (OER) is very important and even decisive in many electrochemical energy storage/conversion technologies, with an urgent need for cost-efficient catalysts to promote its kinetic behavior. Here, we synthesized a unique hybrid catalyst characterized by ultrafine cobalt/iron mixed oxide domains embedded in two-dimensional (2D) monolayer hydroxides through thermal reconstruction of layered double hydroxide precursors, which exhibits excellent OER performance in alkaline media, much superior to state-of-the-art iridium oxide catalyst. In addition to the structural advantages, the chemical coordination evolution was found to achieve metal electronic tuning in favor of intrinsic activity, and in-situ bond hydroxyl groups beneficial to conductivity and hydrophilicity, contributing together to OER kinetics. Coordination adaption of transition metal sites suggests an intuitive active-site descriptor with high-covalent transition metal-oxy-hydroxyl coordination. This work not only renders a cost-effective OER catalyst, but also provides a universal guideline for transition metal site activation.

析氧反应（OER）在许多电化学储能/转化技术中非常重要，甚至是决定性的，迫切需要具有成本效益的催化剂来促进其动力学行为。在这里，我们合成了一种独特的混合催化剂，其特征在于通过层状双氢氧化物前体的热重构嵌入二维 (2D) 单层氢氧化物中的超细钴/铁混合氧化物域，该催化剂在碱性介质中表现出优异的 OER 性能，远优于 state-最先进的氧化铱催化剂。除了结构优势外，还发现化学配位演化实现了有利于内在活性的金属电子调谐，以及有利于导电性和亲水性的原位键羟基，共同促进了 OER 动力学。过渡金属位点的配位适应表明具有高共价过渡金属-氧-羟基配位的直观活性位点描述符。这项工作不仅提供了一种具有成本效益的 OER 催化剂，而且还为过渡金属位点活化提供了通用指南。