化学
铂金
共价键
电化学
电解质
无机化学
金属
碱金属
电催化剂
甲醇
催化作用
电极
物理化学
有机化学
作者
Dušan Strmčnik,Kensaku Kodama,Dennis Van Vliet,Jeffrey Greeley,Vojislav R. Stamenković,Nenad M. Marković
出处
期刊:Nature Chemistry
[Nature Portfolio]
日期:2009-08-16
卷期号:1 (6): 466-472
被引量:662
摘要
The classic models of metal electrode-electrolyte interfaces generally focus on either covalent interactions between adsorbates and solid surfaces or on long-range electrolyte-metal electrostatic interactions. Here we demonstrate that these traditional models are insufficient. To understand electrocatalytic trends in the oxygen reduction reaction (ORR), the hydrogen oxidation reaction (HOR) and the oxidation of methanol on platinum surfaces in alkaline electrolytes, non-covalent interactions must be considered. We find that non-covalent interactions between hydrated alkali metal cations M(+)(H(2)O)(x) and adsorbed OH (OH(ad)) species increase in the same order as the hydration energies of the corresponding cations (Li(+) >> Na(+) > K(+) > Cs(+)) and also correspond to an increase in the concentration of OH(ad)-M(+)(H(2)O)(x) clusters at the interface. These trends are inversely proportional to the activities of the ORR, the HOR and the oxidation of methanol on platinum (Cs(+) > K(+) > Na(+) >> Li(+)), which suggests that the clusters block the platinum active sites for electrocatalytic reactions.
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