Sulfur-resistant methane combustion invoked by surface property regulation on palladium-based catalysts

Abstract

Improving sulfur resistance of palladium-based catalysts is crucial for the sustained and efficient methane combustion. Herein, the surface property of catalysts was rationally tailored to tune the dynamic behavior of sulfur species on active sites and supports, which was qualitatively and quantitatively studied through a combination of in-situ and on-line characterizations. Results reveal that the content of accumulated sulfur species in catalysts increased linearly (0.20–0.59 mmol SO2·g−1) with the rise of the surface basic sites, while it was restrained in catalysts with high surface acidity. The zirconium doped alumina supported palladium catalyst exhibited a moderate surface acidity/basicity, meanwhile it showed an excellent catalytic activity in the presence of SO2 and after regeneration. Its enhanced sulfur resistance derived from the proper interaction between supports and sulfur species, the facile decomposition of zirconium sulfates, the suppressed formation of surface/bulk aluminum sulfates, as well as the effective regeneration of PdO phase. The established quantitative correlation between accumulated sulfur species, surface acidity/basicity and catalytic performance paves the way to develop sulfur-resistant palladium-based catalysts for oxidation reactions.