Broadly, the oxygen evolution reaction (OER) has been deeply understood as a significant part of energy conversion and storage. Nevertheless, the anions in the OER catalysts have been neglected for various reasons such as inactive sites, dissolution, and oxidation, amongst others. Herein, we applied a model catalyst s-Ni(OH)₂ to track the anionic behavior in the catalyst during the electrochemical process to fill this gap. The advanced operando synchrotron radiation Fourier transform infrared (SR-FTIR) spectroscopy, synchrotron radiation photoelectron spectroscopy (SRPES) depth detection and differential X-ray absorption fine structure (Δ-XAFS) spectrum jointly point out that some oxidized sulfur species (SO₄²⁻) will self-optimize new Ni–S bonds during OER process. Such amazing anionic self-optimization (ASO) behavior has never been observed in the OER process. Subsequently, the optimization-derived component shows a significantly improved electrocatalytic performance (activity, stability, etc.) compared to reference catalyst Ni(OH)₂. Theoretical calculation further suggests that the ASO process indeed derives a thermodynamically stable structure of the OER catalyst, and then gives its superb catalytic performance by optimizing the thermodynamic and kinetic processes in the OER, respectively. This work demonstrates the vital role of anions in the electrochemical process, which will open up new perspectives for understanding OER and provide some new ideas in related fields (especially catalysis and chemistry).

从广义上讲，析氧反应 (OER) 已被深入理解为能量转换和储存的重要组成部分。然而，OER 催化剂中的阴离子由于各种原因而被忽略，例如惰性位点、溶解和氧化等。在此，我们应用模型催化剂 s-Ni(OH) ₂来跟踪电化学过程中催化剂中的阴离子行为，以填补这一空白。先进的原位同步辐射傅立叶变换红外（SR-FTIR）光谱、同步辐射光电子能谱（SRPES）深度检测和微分X射线吸收精细结构（Δ-XAFS）光谱共同指出一些氧化硫物种（SO ₄ ^{2 −}) 将在 OER 过程中自我优化新的 Ni-S 键。在 OER 过程中从未观察到如此惊人的阴离子自优化 (ASO) 行为。_{随后，与参考催化剂 Ni(OH) 2}相比，优化衍生的组分显示出显着改善的电催化性能（活性、稳定性等）。理论计算进一步表明，ASO 过程确实衍生出 OER 催化剂的热力学稳定结构，然后分别通过优化 OER 中的热力学和动力学过程来赋予其卓越的催化性能。这项工作证明了阴离子在电化学过程中的重要作用，这将为理解 OER 开辟新的视角，并为相关领域（尤其是催化和化学）提供一些新思路。