Preparation and characterization of Sm3+/Tm3+ co-doped BiVO4 micro-squares and their photocatalytic performance for CO2 reduction

Solar-driven photocatalytic reduction of CO2 to fuels and chemicals with added value has attracted intense attention. Here, the Sm3+/Tm3+ co-doped BiVO4 micro-squares were synthesized by hydrothermal method. The prepared samples were characterized by some physicochemical methods such as XRD, FT-IR, SEM, TEM, XPS, UV–Vis DRS, EPR, N2 physisorption -desorption and electrochemical analysis. The CO2 reduction ability of the catalysts with different rare earth content was evaluated under xenon lamp irradiation. We found that BiVO4 photocatalyst co-doped with 10%Sm and 10%Tm (mole percent) showed the remarkable photocatalytic activity for CO and CH4 production. The CO production rate over 10%Sm/10%Tm/BiVO4 was around 5 times higher than that of pure BiVO4 and single rare earth doped BiVO4. The enhanced activity can be attributed that the Sm3+/Tm3+ co-doping reduced the recombination rate of photogenerated electrons and holes, provides additional light absorption and more active sites for CO2 reduction.