Fig. 6: Photocatalytic performance of oxides in the batch reactor without external heating. Initial reactants were 15 psi of CO2 and 15 psi of H2 (total pressure of ca. 2 bar).

a Non-stoichiometry dependent CO production rates of the c-TiO2@a-TiO2-x(OH)y under full-spectrum Xe light, 4.0 W cm−2. b Stability of c-TiO2@a-TiO2-x(OH)y under full-spectrum Xe light (4.0 W cm−2) in 8 h. c CO production rates of c-TiO2@a-TiO2-x(OH)y, pristine c-TiO2 and 2% Na/c-TiO2 under visible light (2.8 W cm−2).