Diverse Effects of SO₂-Induced Pt–O–SO₃ on the Catalytic Oxidation of C₃H₆ and C₃H₈

Abstract

The effects of sulfur dioxide (SO 2 ) in the catalytic purification of short-chain hydrocarbons are still controversial, and the exact role of SO 2 on adsorption and reaction pathways during the catalytic oxidation of different volatile organic compounds (VOCs) remains unclear. Herein, a three-dimensional ordered macroporous Ce 0.8 Zr 0.2 O 2 supported Pt nanoparticle monolithic catalyst (Pt/OM CZO) was synthesized to investigate these effects. Our findings uncover the diverse effects of SO 2: Upon SO 2 treatment, the coupling between the S 3p and Pt 5d orbitals promotes the Pt–O–SO 3 structure in situ formed on the catalyst surface. The propene (C 3 H 6 ) molecule readily binds with the oxygen atom in Pt–O–SO 3, resulting in the accumulation of acetone and carbon deposition, thereby hindering C 3 H 6 oxidation. Conversely, a cleaved oxygen atom within the Pt–O–SO 3 structure enhances propane (C 3 H 8 ) adsorption and activates the C–H bond, facilitating C 3 H 8 oxidation. These insights are pivotal for advancing the frontier of sulfur-tolerant catalysts, addressing both economic and environmental challenges.