Designing ordered mesoporous confined Pt/Ti0.1AlOy catalysts for the catalytic combustion of propane

Abstract

In this work, two ordered mesoporous catalysts with different confined structures were successfully constructed for the catalytic combustion of propane. Notably, framework-confined Pt/Ti_0.1AlO_y-EISA catalysts were prepared using a one-step evaporation-induced self-assembly (EISA) technique, and we observed that the 0.3%Pt/Ti_0.1AlO_y-EISA catalyst exhibited superior catalytic activity for propane oxidation due to the dual effects of the dispersion of Pt nanoparticles and abundant surface adsorbed oxygen species (O_ads). To further investigate the influence of the location of the active sites, we also prepared pore-confined Pt/Ti_0.1AlO_y-EISA catalysts, and it was verified that the framework-confined catalyst (0.3%Pt/Ti_0.1AlO_y-EISA) shows better activity and thermal stability than the pore-confined 0.3%Pt/Ti_0.1AlO_y-VI catalyst under the same Pt loading. Through a series of characterization studies, it is considered that the framework-confined 0.3%Pt/Ti_0.1AlO_y-EISA catalyst has higher Pt dispersion than the pore-confined 0.3%Pt/Ti_0.1AlO_y-VI catalyst. Interestingly, the pore-confined catalyst has better water and sulfur resistance than the framework-confined catalyst, because the pores protect the active sites from being covered with sulfate to some extent. The sulfate increases the acidity of the catalyst, thereby improving the water and sulfur resistance of the 0.3%Pt/Ti_0.1AlO_y-VI catalyst. The reaction mechanism of the catalytic combustion process of propane was analyzed via in situ DRIFTS experiments, and the Langmuir Hinshelwood (L-H) mechanism was proposed to be the possible reaction mechanism.