析氧
化学
电解质
镍
无机化学
介电谱
碱金属
电化学
拉曼光谱
催化作用
氧气
杂质
电极
物理化学
有机化学
物理
光学
作者
Amanda C. Garcia,Thomas Touzalin,Celine Nieuwland,Nickson Perini,Marc T. M. Koper
标识
DOI:10.1002/anie.201905501
摘要
Abstract Herein, the effect of the alkali cation (Li + , Na + , K + , and Cs + ) in alkaline electrolytes with and without Fe impurities is investigated for enhancing the activity of nickel oxyhydroxide (NiOOH) for the oxygen evolution reaction (OER). Cyclic voltammograms show that Fe impurities have a significant catalytic effect on OER activity; however, both under purified and unpurified conditions, the trend in OER activity is Cs + > Na + > K + > Li + , suggesting an intrinsic cation effect of the OER activity on Fe‐free Ni oxyhydroxide. In situ surface enhanced Raman spectroscopy (SERS), shows this cation dependence is related to the formation of superoxo OER intermediate (NiOO − ). The electrochemically active surface area, evaluated by electrochemical impedance spectroscopy (EIS), is not influenced significantly by the cation. We postulate that the cations interact with the Ni−OO − species leading to the formation of NiOO − −M + species that is stabilized better by bigger cations (Cs + ). This species would then act as the precursor to O 2 evolution, explaining the higher activity.
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