Spinel oxides have attracted growing interest over the years for catalysing the oxygen evolution reaction (OER) due to their efficiency and cost-effectiveness, but fundamental understanding of their structure–property relationships remains elusive. Here we demonstrate that the OER activity on spinel oxides is intrinsically dominated by the covalency competition between tetrahedral and octahedral sites. The competition fabricates an asymmetric M_T−O−M_O backbone where the bond with weaker metal–oxygen covalency determines the exposure of cation sites and therefore the activity. Driven by this finding, a dataset with more than 300 spinel oxides is computed and used to train a machine-learning model for screening the covalency competition in spinel oxides, with a mean absolute error of 0.05 eV. [Mn]_T[Al_0.5Mn_1.5]_OO₄ is predicted to be a highly active OER catalyst and subsequent experimental results confirm its superior activity. This work sets mechanistic principles of spinel oxides for water oxidation, which may be extendable to other applications.

多年来，尖晶石氧化物因其效率和成本效益而吸引了人们对催化氧释放反应（OER）的兴趣，但对它们的结构-性质关系的基本了解仍然难以捉摸。在这里，我们证明了尖晶石氧化物的OER活性本质上是由四面体和八面体位点之间的共价竞争所决定。竞争制造了不对称的M _T -O-M _O具有较弱的金属-氧共价键的键决定了阳离子位点的暴露并因此决定了活性。在这一发现的驱动下，计算出具有300多种尖晶石氧化物的数据集，并将其用于训练机器学习模型，以筛选尖晶石氧化物的共价竞争，平均绝对误差为0.05 eV。预计[Mn] _T [Al _0.5 Mn _1.5 ] _O O ₄是高活性的OER催化剂，随后的实验结果证实了其优异的活性。这项工作设定了尖晶石氧化物用于水氧化的机理原理，可以扩展到其他应用。