Improved performance of tri-doped photocatalyst SrTiO3:Rh/Ta/F for H2 evolution under visible light irradiation

A photocatalyst for visible light irradiation was prepared by simultaneously doping SrTiO3 with F− anion and Rh3+ and Ta5+ cations for the first time through a spray pyrolysis process. The ternary doping of F− contributed to the reduction of Ti4+ and Rh4+ to Ti3+ and Rh3+, respectively, by generating extra electron in the lattice. The partially substituted structure of the photocatalyst could be expressed as Sr(Ti4+1−2x−zTi3+zRh3+x−yRh4+yTa5+x)(O2−3−wF−w). The doping of F− into SrTiO3:Rh/Ta increased the photocatalytic hydrogen evolution rate to 4123.7 μmol g−1 h−1 (quantum efficiency: 6.60%) under visible light irradiation, which was 1.93 times higher than that of SrTiO3:Rh/Ta. The optimum composition of dopants for maximum hydrogen evolution rate was Rh (0.15 mol%), Ta (0.15 mol%), and F (6.0 mol%).