First-Principles Analysis of Oxygen-Containing Adsorbates Formed from the Electrochemical Discharge of Water on Pt(111)

A combination of density functional theory (DFT) calculations and dynamic Monte Carlo (DMC) simulations was employed to study the process of O-containing adsorbates formed from the electrochemical discharge of water on Pt(111) in acidic environment. Potential-dependent activation energy and rate coefficients, as input for DMC simulations, were obtained for the electrochemical reactions and for use in DFT calculations. From DMC simulations, we find that OHads is the dominant adsorbate between 0.5−0.8 V, but above 0.8 V OHads and Oads coexist. Ordered structures are found for OHads at 0.8 V and for Oads at 0.9 V. These results agree well with cyclic voltammetry and electrochemical−X-ray photoelectron spectroscopy measurements.