Enhanced VOCs adsorption and oxidation by hydrophobic-layer-modified YMn2O5 mullite catalyst with ultralow single-atom Pt loading

Abstract

Hydrophobic-layer-modified mullite YMn2O5 catalysts with ultralow single-atom Pt loadings and three-dimensionally ordered macroporous (3DOM) structures (denoted as × wt% Pt/YMO/Ph-3DOM) were synthesized via a facile strategy and assessed for toluene oxidation. The 3DOM structure provides a large surface area, while the ultralow Pt doping (0.1 wt%) reduces catalyst costs, improves low-temperature reducibility, and provides more oxygen vacancies, which are beneficial for O2 adsorption and activation. Surface modification with phenyltriethoxysilane significantly improves activity under wet conditions and promotes the adsorption of toluene. 0.1 wt% Pt/YMO/Ph-3DOM achieves 100% toluene oxidation at 160 °C at a WHSV of 36,000 mL g−1h−1 under wet conditions. In-situ DRIFTS experiments were carried out to investigate the reaction mechanism. Furthermore, DFT calculations were used to investigate the adsorption and activation of O2, toluene, and the intermediates on the catalyst surface, providing new insight into VOC oxidation for future investigations.