REACTION-MECHANISM AND ROLE OF THE SUPPORT IN THE PARTIAL OXIDATION OF METHANE ON RH AL2O3/

The partial oxidation of CH4 over Rh/Al2O3 was studied by means of tem poral analysis of products (TAP). CH4 was found to adsorb dissociative ly on reduced metal sites. Oxygen preadsorption decreases the methane adsorption rate. The oxidation products under oxidative conditions are CO2 and H2O. The selectivity towards CO and H-2 rises to almost 100% as the conditions become more reductive. Water adsorbed on the support acts as an oxygen source through the inverse spillover of water or hy droxyl onto the Rh particles. A reaction scheme for the partial oxidat ion of methane is presented and the elementary reactions that give ove rall steam reforming, CO2 reforming, and water-gas shift are discussed . (C) 1996 Academic Press, Inc.