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

Abstract

The effects of sulfur dioxide (SO₂) in the catalytic purification of short-chain hydrocarbons are still controversial, and the exact role of SO₂ on adsorption and reaction pathways during the catalytic oxidation of different volatile organic compounds (VOCs) remains unclear. Herein, a three-dimensional ordered macroporous Ce_0.8Zr_0.2O₂ supported Pt nanoparticle monolithic catalyst (Pt/OM CZO) was synthesized to investigate these effects. Our findings uncover the diverse effects of SO₂: Upon SO₂ treatment, the coupling between the S 3p and Pt 5d orbitals promotes the Pt-O-SO₃ structure in situ formed on the catalyst surface. The propene (C₃H₆) molecule readily binds with the oxygen atom in Pt-O-SO₃, resulting in the accumulation of acetone and carbon deposition, thereby hindering C₃H₆ oxidation. Conversely, a cleaved oxygen atom within the Pt-O-SO₃ structure enhances propane (C₃H₈) adsorption and activates the C-H bond, facilitating C₃H₈ oxidation. These insights are pivotal for advancing the frontier of sulfur-tolerant catalysts, addressing both economic and environmental challenges.