Combined First-Principles Molecular Dynamics/Density Functional Theory Study of Ammonia Electrooxidation on Pt(100) Electrode

A combined first-principles molecular dynamics/density functional theory study of the electrooxidation of ammonia is conducted to gain an atomic-level understanding of the electrocatalytic processes at the Pt(100)/alkaline solution interface and to probe the mechanistic details of ammonia electrooxidation on the metal surface. A systematic study of adsorption and relative stability of ammonia and the intermediate species on the Pt(100) surface as a function of potential is carried out and activation energy profiles for the mechanistic steps in the ammonia oxidation are presented. The reaction mechanism is potential dependent: the modeling study supports the Oswin and Salomon’s mechanism for moderate surface potentials (≥+0.5 V vs RHE), and the Gerischer and Maurer’s mechanism for lower potentials (