Size-dependent Pt dispersion and hydroxyl-assisted synergistic mechanism for propane complete oxidation over Pt/Al2O3 catalyst

Abstract

Complete oxidation of propane has attracted widespread attention in the treatment of volatile organic compounds (VOCs) from Fischer-Tropsch synthesis tail gas. Pt-based catalysts have been considered highly promising catalysts for the catalytic oxidation of propane due to their high-activity. However, despite the recognized importance of the synergistic effect between Pt nanoparticles (NPs) and support materials, the detailed reaction mechanism investigation remains limited. In this work, we demonstrate that the Pt/Al₂O₃ catalyst exhibits improved propane catalytic performance, which is attributed to the synergistic interaction between Pt NPs and surface hydroxyl groups on the support. The improved Pt dispersion in Pt/Al₂O₃ catalysts with smaller Pt NPs facilitates the spillover of gaseous oxygen species and the stabilization of active sites for propane oxidation. Furthermore, in-situ DRIFTS characterization and density functional theory (DFT) calculation confirm that surface hydroxyl groups on Al₂O₃ effectively reduce the activation barrier for C-H bond cleavage, thereby improving the reactivity of propane molecules. This work provides a novel insight into metal-support synergy for propane oxidation, which offers strategic guidance for the rational design of efficient catalysts in hydrocarbon conversion processes.