Engineering a Mesoporous Pt/Ce-ZSM-5 Catalyst by a Confined Encapsulation Strategy for Low-Temperature Catalytic Combustion of Toluene

Abstract

Zeolites with molecular-sized pores and organized distributions have been proven to be excellent catalytic carriers, particularly ZSM-5, which is widely used in catalyst design due to its high activity in aromatic hydrocarbon conversion. In this study, we innovatively introduced rare earth Ce species into the mesoporous zeolite ZSM-5 system through in situ synthesis and then encapsulated Pt species onto the mesoporous Ce-ZSM-5, resulting in a novel Pt/Ce-ZSM-5 catalyst with a “rare earth-zeolite-precious metal” synergistic effect. The design philosophy of this catalyst is to enhance the interaction between Ce and the zeolite carrier and to improve the dispersion of Pt nanoparticles, thereby elevating the acidity, active oxygen content, and overall catalytic performance of the catalyst. Experimental results show that when the doping amount of Ce is 10 wt % and the loading amount of Pt is 0.8 wt %, the Pt/Ce-ZSM-5 catalyst exhibits excellent catalytic activity and stability in the catalytic combustion of toluene. Through systematic characterizations, we revealed the synergistic mechanism among the mesoporous structure of the carrier, Ce species, and Pt species, which not only enhanced the chemical activity on the catalyst surface but also effectively regulated the distribution of Pt species, thus improving the catalytic efficiency. This research not only provides a new theoretical framework for the design of efficient Pt-based catalysts but also deepens our understanding of the mechanism by which rare-earth-element-doped zeolites modulate the performance of precious metal catalysts.