Photocatalytic CO2 Reduction using Non‐Titanium Metal Oxides and Sulfides

Abstract Titanium dioxide (TiO 2 ) is by far the most widely used photocatalyst both for the degradation of pollutants and in the field of renewable energies for the production of solar fuels. However, TiO 2 has strong limitations in CO 2 reduction, particularly under visible light irradiation. The flat‐band potential of electrons in the conduction band of TiO 2 is lower than that required for CO 2 reduction and, therefore, it seems appropriate to develop and validate materials other than TiO 2 . In addition, the photoresponse of TiO 2 requires photons of wavelengths in the UV range shorter than 380 nm and strategies to implement a visible‐light photoresponse on TiO 2 by doping have not been completely satisfactory particularly because of problems in reproducibility and stability of the materials. For these reasons, we focus in this Review on semiconductors other than TiO 2 that show photocatalytic activity in CO 2 reduction. Attention has been paid to the irradiation conditions to put the productivity data into context. The role of co‐catalyst and heterojunctions to increase the efficiency of charge separation is also discussed. Our aim is to describe the state of the art in the field of photocatalytic CO 2 reduction using materials other than TiO 2 , trying to trigger further research in this area.