Theoretische Untersuchungen zur Sauerstoffreduktion an Übergangsmetall-Elektroden

Abstract

A ReaxFF reactive interaction potential for Pt/O is developed using a first-principles-based multiscale approach and applied to investigate model-systems relevant to the oxygen reduction reaction (ORR) on platinum. Investigations of Pt(111) surface oxidation under various external conditions (from UHV to near-ambient-pressures) reveal two key mechanistic steps as the surface coverage increases, namely platinum surface buckling and subsequent oxygen absorption into the surface. Thermodynamically stable surface oxides on Pt(111) are predicted for the first time, which may be responsible for the sluggish kinetics of the ORR. Finally, reactive molecular dynamics studies provide new ideas for mechanistic pathways involved in the formation of water from hydrogen and oxygen gas on Pt(111).