The partial oxidation of methane to syngas (POM) over a Rh/SiO2 catalyst was investigated by temperature program desorption (TPD), temperature program reduction (TPR), temperature program surface reaction (TPSR), and temperature program reaction. Interaction of CH4/Ar or CH4/O-2/Ar with Rh/SiO2 catalyst was examined by pulse and transient reaction techniques. The experiment results showed that the POM over Rh/SiO2 catalyst is through a dissociation-oxidizing mechanism. Methane dissociates to surface species, such as CHx (x = 1-3) and adsorbed atomic hydrogen on the catalyst, then the surface CH, (x = 1-3) species combine with the surface active oxygen species to generate CO and H-2. CO2 could come from further oxidation of CHx, CO, and other carbon species. (C) 2004 Elsevier B.V. All rights reserved.