Kinetics and mechanism of the electrochemical reduction of a platinum oxide monolayer in molten alkaline bisulphates under constant ageing conditions

Abstract

The electrochemical reduction of a platinum oxide monolayer anodically formed in NaHSO⁴−KHSO⁴ and KHSO⁴ melts is investigated under equivalent ageing conditions from 185 to 315°C with application of the linear potential sweep technique. The experimental potentiodynamic current/potential profiles are reproduced with equations derived from a reaction mechanism involving an initial electron transfer reaction followed by a second order recombination step under Temkin conditions. The rate equations imply negative Temkin factors which, in absolute value, increase with temperature.