The electrooxidation of carbon monoxide is a typical example of structure sensitivity in electrocatalysis for fuel cells. Understanding the structure sensitivity is crucial in designing highly efficient catalysts and elucidating reaction mechanisms. Conventionally, only the reactivity of active sites was considered and optimized. However, how the reactant chemically moves to the active site has not been well studied. In this work, we found that CO_ad hopping is a general phenomenon on noble metal surfaces such as platinum, iridium, rhodium, and palladium in the case of CO monolayer electrooxidation. Differences in the performances of CO_ad stripping on platinum nanoparticles with different surface structures reveal that the CO_ad hopping rate is structure sensitive as well. Assisted by a diffusion modeling and density functional theory calculations, it is demonstrated that the structure sensitivity is as a result of a compromise between CO_ad chemical diffusivity and reactivity with OH_ad.

一氧化碳的电氧化是燃料电池电催化中结构敏感性的典型实例。了解结构敏感性对于设计高效催化剂和阐明反应机理至关重要。常规上，仅考虑和优化活性位点的反应性。但是，尚未很好地研究反应物如何化学移动到活性位点。在这项工作中，我们发现，CO_广告跳频是如铂，铱，铑和钯中的CO单层电氧化的情况下，上贵金属的普遍现象面这样。在具有不同表面结构的铂纳米颗粒上CO _ad剥离性能的差异表明，CO _ad跳变率对结构也很敏感。借助于扩散建模和密度泛函理论计算，证明了结构敏感性是由于CO _ad化学扩散率和与OH _ad的反应性之间折衷的结果。