Unveiling the confinement and interface effect on low temperature degradation of toluene over mesoporous zeolite encapsulated Pt-CeO2 catalyst

Abstract

The efficient degradation of volatile organic compounds (VOCs) at low temperatures is urgently needed due to the serious environmental and health hazards they pose. While precious metal-based catalysts offer excellent performance, their application is limited by high-temperature sintering and aggregation. Therefore, inhibiting the migration and aggregation of precious metals during the reaction process can effectively improve their utilization and alleviate catalyst deactivation. In this study, a novel encapsulated catalyst (Pt-CeO@meso-S1) containing Pt-CeO2 interfaces was constructed using mesoporous-rich zeolite as a shell layer and applied to the catalytic oxidation of toluene. The introduction of CeO2 constructed a Pt-CeO2 active interface that promoted the low-temperature degradation of toluene, achieving complete oxidation of toluene at 160 ℃. The crystalline phase transition strategy enhanced the specific surface area, improving the dispersion of platinum and facilitating the construction of the Pt-CeO2 interface. The zeolite shell and mesoporous pores effectively confined/stabilized the Pt-CeO2 active components and inhibited platinum sintering, resulting in outstanding water resistance and high-temperature stability. DFT calculations demonstrated that the presence of the Pt-CeO2 active interfaces reduced oxygen vacancy formation energy and facilitated gas-phase oxygen activation. DFT calculations demonstrated that the presence of the Pt-CeO2 active interfaces reduces the oxygen vacancy formation energy and boosts the activation of gas-phase oxygen. The Mars-van-Krevelen (MvK) mechanism governing toluene degradation over Pt-CeO2@meso-S1 was revealed by in situ DRIFTS. This work provides a promising candidate for industrial high-performance catalytic removal of VOCs at low temperatures.