Methane catalytic combustion over flame spray pyrolysis-synthesized Pd-Pt/CeO₂ catalyst

Flame spray pyrolysis (FSP) is a versatile, rapid, and scalable preparation technique for the nanocatalysts. CeO₂ and Pt-CeO₂ carriers, Pd-Pt-CeO₂ catalyst were synthesized by flame spray pyrolysis, and then Pd-Pt bimetallic catalysts were prepared by impregnation method, and as-obtained Pd-Pt catalysts were tested in the methane combustion. The physicochemical properties of the catalysts were characterized by ICP, XRD, TEM, BET, H₂-TPR, XPS, and Raman. TEM results showed that Pd and Pt species were highly dispersed in CeO₂ carriers in Pd-Pt/CeO₂ catalysts. Compared with the Pd-Pt-CeO₂(OS-FSP) catalyst prepared by one-step flame spray pyrolysis, the catalytic activity of the Pd-Pt/CeO₂(0.25)-WI prepared by co-impregnation was higher, with its t₅₀ reduced by 60 ℃, and no deactivation was seen for 60 h. It is attributed to the fact that the Pd-Pt/CeO₂(0.25)-WI catalyst has a higher molar ratio of Pd⁰/Pd²⁺ and Ce³⁺/Ce⁴⁺ on the surface of the catalyst and more lattice oxygen, resulting in an excellent performance during the methane combustion.