过电位
介电谱
化学
循环伏安法
动力学
旋转圆盘电极
电化学
分析化学(期刊)
电极
电化学动力学
催化作用
伏安法
氢
电催化剂
物理化学
有机化学
量子力学
物理
作者
Sergey Pronkin,Antoine Bonnefont,Pavel S. Ruvinskiy,Elena R. Savinova
标识
DOI:10.1016/j.electacta.2010.01.060
摘要
This work reports on the kinetics of the hydrogen oxidation reaction (HOR) on model Pd nanoparticles supported on a low surface area carbon substrate. Two Pd/C samples, with the average particle size 2.6 and 4.0 nm were used. The structure of the catalysts was characterized with the ex situ (electron microscopy) and in situ (electrochemical) methods. We utilized the electrochemical impedance spectroscopy (EIS) and the rotating disk electrode (RDE) voltammetry to study the kinetics of the HOR on Pd/C. The relevance of these techniques for elucidating the kinetics and the mechanism of the HOR on Pd/C was explored. The experimental results suggest that the catalytic activity of Pd in the HOR is more than 2 orders of magnitude lower than that of Pt, and does not depend on the particle size in the range from 2.6 to 4.0 nm. Computational modeling of the experimental steady-state (RDE) and non-steady-state (EIS) data shows that the reaction kinetics can be adequately described within Heyrovsky–Volmer mechanism, with the rate constants υ0H = (8.8 ± 1.5) × 10−10 mol cm−2 s−1 and υ0V = (1.0 ± 0.3) × 10−8 mol cm−2 s−1. The model suggests that underpotentially deposited hydrogen HUPD is unlikely to be the active intermediate Had of the HOR. It is concluded that the surface coverage of Had deviates from that of HUPD with increasing overpotential, and the lateral interactions within Had adlayer are weak.
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