ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

Theunis Nel, Hermanus C. M. Vosloo, Jean I. du Toit, and Cornelia G. C. E. van Sittert

Laboratory for Applied Molecular Modelling, Chemical Resource Beneficiation, North-West University, Potchefstroom, South Africa

E-mail: DuToit.Jean@nwu.ac.za

Abstract:

Catalytic SO₂ oxidation with H₂O and O₂ on Pt is a common research topic due to numerous possible surface reactions, products and applications thereof. Recently, aqueous SO₂ oxidation on Pt has been the focus of several papers, given its application in H₂ production through the hybrid sulphur cycle. In this paper, several aspects of SO₂ 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 SO₂ 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 SO₂ reduction to S, and recovery of the Pt catalyst via reoxidation of adsorbed S. Adsorption and desorption of sulphur oxides, H₂O, H₂ and O₂ are discussed in terms of geometry and site preference, forming fundamental steps in aqueous SO₂ oxidation on Pt. The influence of temperature, potential, and solvents on SO₂ adsorption, reactions and the intermediates formed on Pt is considered. The relationship between coadsorption, surface coverage and SO₂-H₂O reaction mechanisms on Pt is discussed. The influence of steps on H₂O, H₂, and O₂ adsorption and diffusion on Pt is noted, as well as the possible impact on the SO₂-H₂O reaction mechanism. Lastly, these aspects of aqueous SO₂ oxidation on Pt are summarised.

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04814-5

Chemical Papers 80 (8) 8431–8459 (2026)