CO2 Reduction Performance with Double-Layered Cu/TiO2 and P4O10/TiO2 as Photocatalysts under Different Light Illumination Conditions

This paper presents an experimental study of using a double-layered Cu/TiO2 and P4O10/TiO2 as photocatalysts for CO2 reduction with an extended wavelength of range light from ultraviolet light (UV) to infrared light (IR). The lights studied were UV + visible light (VIS) + IR, VIS + IR and IR only. This study also investigated the impact of the molar ratio of CO2:H2O on the CO2 reduction performance. This study revealed that the optimum molar ratio of CO2:H2O to produce CO was 1:1, irrespective of light illumination condition, which matched the theoretical molar ratio to produce CO according to the reaction scheme of CO2 reduction with H2O. Comparing the results of double-layered Cu/TiO2 and P4O10/TiO2 with those of double-layered TiO2 obtained under the UV + VIS + IR light illumination condition, the highest concentration of formed CO and the molar quantity of formed CO per unit weight of the photocatalyst increased by 281 ppmV and 0.8 μmol/g, in the case of the molar ratio of CO2:H2O = 1:1. With IR-only illumination, the highest concentration of formed CO and the molar quantity of CO formed per unit weight of the photocatalyst was 251 ppmV and 4.7 μmol/g, respectively.