摘要：

Electrochemical reactions catalyzed by metal electrode, despite their huge importance in industry, are not well understood at the atomic level. In relevance to water electrolysis, the oxygen coupling reaction on Pt metal surfaces is systematically investigated in this work by combining periodic density functional theory calculations with a new theoretical approach to mimic the electrochemical environment. In our approach, the surface is explicitly polarized by adding/subtracting charges and the counter charges are placed as Gaussian-distributed plane charges in a vacuum. With this method, the surface phase diagrams for both the closed-packed Pt(111) and stepped Pt(211) are determined, which demonstrates that stepped surface sites can better accumulate oxidative species and thus reach to a higher local O coverage compared to Pt(111) at a given potential. The water environment is proved to affect the phase diagram marginally. By fully exploring the possible oxygen coupling channels on Pt surfaces, we show t...

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