Catalytic Combustion of Lean Methane at Low Temperature Over Palladium on a CoO x –SiO2 Composite Support

Abstract

A composite support of CoO x –SiO2 was obtained through modifying silica with cobalt of different loadings; with CoO x –SiO2 as the support, a series of Pd/CoO x –SiO2 catalysts were prepared for the combustion of lean methane at low temperature. The effects of CoO loading and palladium precursor on the catalytic performance of Pd/CoO x –SiO2 were investigated. The Pd/CoO x –SiO2 catalyst containing 20 wt% CoO and 1 wt% Pd with acetate as palladium precursor performs excellently in lean methane combustion; over it a complete conversion of methane can be achieved at 420 °C and the activity does not show any decline in a long-term test of 120 h. Various characterizations suggested that cobalt species are highly dispersed on the silica of high surface area and there exists a synergetic interaction between palladium and cobalt species, which improves the redox properties of Pd/CoO x –SiO2 and contributes to the excellent catalytic performance in lean methane combustion. Silica modified with cobalt (CoO x –SiO2) is an idea support to prepare Pd/CoO x –SiO2 catalyst of high activity in lean methane combustion; over it a complete conversion of methane can be achieved at 420 °C and the conversion does not show any decline in a long-term test of 120 h.