Laser-induced activation of methane at oxide surfaces: A probe of radical-surface interactions

C-H bond activation was studied via pulsed laser irradiation of oxides in a methane atmosphere. Carbon monoxide was the major product observed at low power densities and room temperature. Significant amounts of C₂ products, ethane, ethylene, and acetylene were formed. CO, C₂H₆, C₂H₄, and C₂H₂ are assigned as primary products of the reaction. Laser-induced methane activation produces ^.CH₃ and :CH₂ radical species in the gas phase via a plasma mechanism and is utilized as a tool to study radical-oxide surface interactions. These reactions are surface sensitive as evidenced by the changes in conversion and product selectivity as a function of oxide pretreatment and oxides used.