Improved catalytic methane combustion of Pd/CeO2 catalysts via porous glass integration

Abstract

Methane combustion catalysts composed of Pd and CeO2 were synthesized through impregnation of porous glasses with cerium nitrate melt and palladium nitrate solution followed by subsequent calcination. They were tested in the temperature range from 150 to 550°C using a feed with 1.0vol% methane in air at a GHSV (gas hourly space velocity) of ∼30,000h−1. The catalyst prepared with a glass possessing a pore diameter of 151nm and a Pd loading of 0.63wt% completely converted methane at 350°C compared to 415°C required for a classically prepared Pd/CeO2 reference. The novel catalyst also showed superior on stream stability as proven in 50h tests. The influence of preparation method, pore size of the glass supports and Pd loading on the activity for CH4 total oxidation was further investigated and correlated with the results of H2-TPR and CO chemisorption. It is suggested that the catalyst activity for methane combustion is determined by both (i) Pd particle size and (ii) surface reducibility of CeO2.