Morphology controlled synthesis of CeTiO4 using molten salts and enhanced photocatalytic activity for CO2 reduction

Incorporation of visible light active semiconductors without doping noble (transition) metals results in remarkably different construction principle of visible light driven photocatalysts in which light absorptions and charge transfer become more flexible and efficiencies are no longer limited in ultraviolet (UV) region. Herein, we provide a strategy to design efficient photocatalysts by introducing visible light sensitive Ce2O3 into UV active TiO2 via molten salt synthesis (MSS) of CeTiO4 for visible light CO2 reduction. By changing salt composition in the MSS process, the nanostructured CeTiO4 was prepared and exhibited distinct morphologies e.g., nanorods (NaClNaH2PO4), polyhedrons (KClNaCl) and cubic (KClNa2SO4), respectively. Of the different morphologies, the nanorods of CeTiO4 showed best photoactiviy with quantum efficiencies of 0.36% and 0.065% for CO and CH4 formation, respectively. The unique morphologies well positioned band edges cause such obvious differences and co-contribute to the high performance effectiveness. This study demonstrates a strategy for the rational design and fabrication of visible light driven photocatalysts with controlled morphology, which in turn, can enhance the control and production of value-added products of CO2 reduction. This is an important step towards realizing the utilization of renewable energy sources, such as solar power, to reduce the concentration of atmospheric CO2 and form green energy sources.