Catalytic membrane materials with a hierarchical porosity and their performance in total oxidation of propene

Pt nanoparticles (Pt-NPs) dispersed in either SiO2 or SiO2–TiO2 hierarchical matrix were investigated for the total oxidation of propene as a typical volatile organic compound. The proposed scalable synthesis method, based on a “one pot” sol–gel pathway enables the encapsulation of isolated Pt-NPs mainly in the organised mesopores and guarantees their accessibility through the connected micropores of the oxide walls. The accessibility and stability of the Pt-NPs into this complex nanostructure were specially studied in this work. Pt–SiO2 membrane materials with 1.7 wt% Pt revealed very efficient catalyst for the combustion of propene, with a light-off temperature lower that 110 °C. Interestingly, thermal treatments of these materials up to 850 °C do not destroy their catalytic activity thanks to the limited thermal growth of Pt-NPs within the hierarchical structure, and in spite of a strong reduction of their specific surface area. SiO2–TiO2 materials with 20 mol% SiO2 also revealed an attractive hierarchical matrix for dispersing efficiently the Pt-NPs and performing the oxidation reaction below 200 °C.