VISIBLE-LIGHT-ASSISTED DECOMPOSITION OF H2O AND PHOTOMETHANATION OF CO2 OVER CEO2-TIO2 CATALYST

The reaction of CO2 and H2O over a CeO2-TiO2 catalyst was performed with irradiation by visible light. The reaction products were H-2, CH4 and O2. The initial rates of formation of H-2 and O2 were 2.75 and 1.28-mu-mol h-1 g-1 respectively. The reaction proceeded through the stoichiometric pbotodecomposition of H2O followed by the methanation of CO2; however, some of the generated O2 was involved in the reoxidation of the reduced ceria or titanium oxide when a catalyst pretreated in H-2 was used. The maximum yield of H-2 was exhibited with highly dispersed 0.5wt.%CeO2-TiO2.