Strontium hydroxyapatites: Catalytic properties in the oxidative dehydrogenation of methane to carbon oxides and hydrogen

Abstract

Strontium hydroxyapatite of various Sr/P ratios catalyzes oxidative dehydrogenation of methane to carbon oxides and hydrogen at a reaction temperature of 600°C. Although the selectivities are essentially independent of the composition of the catalyst, the activity decreases with decreasing concentration of strontium. The relatively high ratio of H₂/CO produced cannot be rationalized either through the oxidation of methanol on the catalyst or the water gas shift reaction, but appears to result primarily from the direct oxidation of methane, with the reaction to produce CO₂ and H₂ proceeding at a rate approximately twice that to CO. New active sites associated with strontium appear to be responsible for the catalytic properties of the hydroxyapatite.