Unraveling the Formation Kinetics of the First Intermediate in the Oxygen Evolution Reaction on MnO x with Different Electron Configurations

作者：Ruifang Wei, Dongfeng Li, Panwang Zhou, Runze Liu, Chenwei Ni, Zeyu Cheng, Xiuli Wang, Can Li · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.4c18273 · 被引用次数：18 · 研究领域：Electrocatalysts for Energy Conversion、Advanced battery technologies research、Electrochemical Analysis and Applications

In the electrocatalytic oxygen evolution reaction (OER), it has been a long-standing issue to establish the relationship between intermediate kinetics, catalyst structures, and OER activity, which is challenging due to the difficulty in following the intermediate kinetics and charge dynamics simultaneously. Here, using home-built operando electrochemical transient absorption (EC-TA) spectroscopy, we succeeded in resolving the kinetics of the first intermediate (*OH species) in the OER catalytic cycle on MnO x -based electrocatalysts, which is consistent with microkinetics simulation. In the formation process of *OH species, proton transfer is slower than electron transfer, resulting in the continuous formation of *OH species after the interruption of the potential pulse. Based on a comparison of *OH formation rates in four MnO x -based catalysts with different electron configurations, the formation rates of *OH species are highly dependent on the coordination symmetry of the corner-shared Mn 3+ O 6 octahedron in the catalyst. The formation rate of *OH species in a catalyst with a corner-shared Mn 3+ O 6 octahedron of D 3d symmetry exhibits a ∼100-fold (2.33 × 10 3 s –1 ) increase compared with that in a catalyst with a corner-shared Mn 3+ O 6 octahedron of D 4h symmetry (2.45 × 10 1 s –1 ). More importantly, the formation rates of *OH species show a positive correlation with the reaction rates of the rate-determining step (RDS) in the OER catalytic cycle. The insight into the...