A kinetic descriptor for the electrolyte effect on the oxygen reduction kinetics on Pt(111)

Abstract Proton-exchange membrane fuel cells demand efficient electrode–electrolyte interfaces to catalyse the oxygen reduction reaction (ORR), kinetics of which depends on energetics surface adsorption and electrolyte environment. Here we show an unanticipated effect non-specifically adsorbed anions ORR a Pt(111) electrode; these trends do not follow usual descriptor, that is *OH binding energy. We propose voltammetry-accessible namely reversibility *O ? transition. This descriptor tracks dependence rates electrolyte, including concentration/identity in acidic media, cations alkaline media ionomers. model relates rate transition, addition thermodynamic energy descriptor. Our also rationalizes different for stepped Pt surfaces versus media.