期刊
ACS CATALYSIS
卷 9, 期 7, 页码 6194-6201出版社
AMER CHEMICAL SOC
DOI: 10.1021/acscatal.9b00268
关键词
hydrogen evolution; electrocatalysis; DFT; microkinetic modeling; hydrogen oxidation; water splitting; kinetics
资金
- U.S. Department of Energy, Chemical Sciences, Geosciences, and Biosciences (CSGB) Division of the Office of Basic Energy Sciences [DE-AC02-76SF00515]
- VILLUM FONDEN [9455]
- Alexander von Humboldt Foundation (AvH)
A long-standing question in electrocatalysis is how the electrolyte pH affects the catalytic activity of proton electron transfer reactions. A prime example for this is the hydrogen evolution/oxidation reaction (HER/HOR) over metal catalysts. While it has long been established that alkaline conditions result in a more sluggish reaction kinetics than in acidic conditions, the underlying reason for this trend remains contentious. We apply density functional calculations to evaluate prevailing hypotheses for the origin of this effect: shifts in hydrogen binding, proton donor, and water reorganization energy. We present a microkinetic model, based on ab initio reaction energetics of all possible elementary steps. Our model shows a good agreement with experimental trends. We find that with increasing pH, the proton donor changes from hydronium to water. Our model suggests that the intrinsically larger barriers for the splitting of water with respect to hydronium are the cause of HER kinetics being slower in alkaline than in acidic media.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据