Dynamic Evolution of Solid–Liquid Electrochemical Interfaces over Single-Atom Active Sites

作者：Hui Su, Wanlin Zhou, Hui Zhang, Wu Zhou, Xu Zhao, Yuanli Li, Meihuan Liu, Weiren Cheng, Qinghua Liu · 发表于：Journal of the American Chemical Society · 年份：2020 · DOI：10.1021/jacs.0c04231 · 被引用次数：226 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Electronic and Structural Properties of Oxides

The structural dynamics of the solid–liquid interfaces (SLEIs) determines the chemistry in all electrochemical processes. Here, by combining multiple operando synchrotron spectroscopies, we identify at the atomic level a general evolution of single-atom Ni at SLEIs into a near-free atom state in the electrochemical oxygen reduction reaction (ORR). We uncover that the single-atom Ni at SLEIs tends to be dynamically released from the nitrogen–carbon substrate and then forms a near-free, isolated-zigzag active site (Ni 1 (2-δ)+ N 2 ) during the reaction. This isolated-zigzag Ni 1 (2-δ)+ N 2 active site facilitates the adsorption and dissociation of O 2 into a crucial *O intermediate within the electrical double layers, realizing a highly efficient single-atom catalyst with the best ORR performance in alkaline solutions reported thus far. These findings may pave a general way for dissecting other important structural dynamic processes at SLEIs, such as hydrogen evolution, oxygen evolution, and CO 2 reduction reactions.