Unifying the Hydrogen Evolution and Oxidation Reactions Kinetics in Base by Identifying the Catalytic Roles of Hydroxyl-Water-Cation Adducts

作者：Ershuai Liu, Jingkun Li, Li Jiao, Huong Thi Thanh Doan, Zeyan Liu, Zipeng Zhao, Yu Huang, K. M. Abraham, Sanjeev Mukerjee, Qingying Jia · 发表于：Journal of the American Chemical Society · 年份：2019 · DOI：10.1021/jacs.8b13228 · 被引用次数：392 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Advanced battery technologies research

Despite the fundamental and practical significance of the hydrogen evolution and oxidation reactions (HER/HOR), their kinetics in base remain unclear. Herein, we show that the alkaline HER/HOR kinetics can be unified by the catalytic roles of the adsorbed hydroxyl (OH ad )-water-alkali metal cation (AM + ) adducts, on the basis of the observations that enriching the OH ad abundance via surface Ni benefits the HER/HOR; increasing the AM + concentration only promotes the HER, while varying the identity of AM + affects both HER/HOR. The presence of OH ad -(H 2 O) x -AM + in the double-layer region facilitates the OH ad removal into the bulk, forming OH – -(H 2 O) x -AM + as per the hard–soft acid–base theory, thereby selectively promoting the HER. It can be detrimental to the HOR as per the bifunctional mechanism, as the AM + destabilizes the OH ad, which is further supported by the CO oxidation results. This new notion may be important for alkaline electrochemistry.