A review of experimental and theoretical insights regarding SO2 oxidation on Pt

Abstract Catalytic SO 2 oxidation with H 2 O and O 2 on Pt is a common research topic due to numerous possible surface reactions, products and applications thereof. Recently, aqueous SO 2 oxidation on Pt has been the focus of several papers, given its application in H 2 production through the hybrid sulphur cycle. In this paper, several aspects of SO 2 oxidation on Pt are discussed, with an emphasis on aqueous oxidation. An overview of reaction mechanisms on catalyst surfaces is provided, including the distinct mechanistic steps involved. Aqueous SO 2 oxidation on Pt is discussed, focussing on the reaction mechanism, including reaction intermediates, sulphur bonds and oxidation states. Catalyst poisoning is discussed in terms of SO 2 reduction to S, and recovery of the Pt catalyst via reoxidation of adsorbed S. Adsorption and desorption of sulphur oxides, H 2 O, H 2 and O 2 are discussed in terms of geometry and site preference, forming fundamental steps in aqueous SO 2 oxidation on Pt. The influence of temperature, potential, and solvents on SO 2 adsorption, reactions and the intermediates formed on Pt is considered. The relationship between coadsorption, surface coverage and SO 2 -H 2 O reaction mechanisms on Pt is discussed. The influence of steps on H 2 O, H 2 , and O 2 adsorption and diffusion on Pt is noted, as well as the possible impact on the SO 2 -H 2 O reaction mechanism. Lastly, these aspects of aqueous SO 2 oxidation on Pt are summarised.