ELECTRON SPECTROSCOPIC STUDY OF ADSORPTION OF METHANE ON TITANIUM-DIOXIDE SURFACES

The chemisorption of methane has been investigated on titanium surface, the polycrystalline TiO2 film surface and the TiO2(100) surface with and without defects (oxygen vacancies). It has been found that the activation of C-H bonds depends on surface oxygen species. The different adsorption behavior between methane adsorption and methane-oxygen coadsorption, together with the different adsorption results on the TiO2(100) surface with and without defects, shows that the electrophilic oxygen species on the surface are active species for the activation of C-H bonds of methane. The temperature dependence of adlayer provides possible evidence for electrophilic oxygen species reacting with CH(x) on the surface.