Photocatalytic Water Splitting for Hydrogen Production with Novel Y2MSbO7 (M = Ga, In, Gd) under Visible Light Irradiation

Novel photocatalysts Y2MSbO7 (M = Ga, In, Gd) were synthesized by the solid state reaction method for the first time. A comparative study on the structural and photocatalytic properties of Y2MSbO7 (M = Ga, In, Gd) was reported. The results showed that Y2GaSbO7, Y2InSbO7 and Y2GdSbO7 crystallized with the pyrochlore-type structure, cubic crystal system, and space group Fd3m. The lattice parameter for Y2GaSbO7 was 10.17981 Å. The lattice parameter for Y2InSbO7 was 10.43213 Å. The lattice parameter for Y2GdSbO7 was 10.50704 Å. The band gap of Y2GaSbO7 was estimated to be 2.245 eV. The band gap of Y2InSbO7 was 2.618 eV. The band gap of Y2GdSbO7 was 2.437 eV. For the photocatalytic water-splitting reaction, H2 or O2 evolution was observed from pure water with Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 as catalyst under visible light irradiation. (Wavelength > 420 nm). Furthermore, H2 and O2 were also evolved by using Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 as a catalyst from CH3OH/H2O and AgNO3/H2O solutions, respectively, under visible light irradiation (λ > 420 nm). Y2GaSbO7 showed the highest activity compared with Y2InSbO7 or Y2GdSbO7. At the same time, Y2InSbO7 showed higher activity compared with Y2GdSbO7. The photocatalytic activities were further improved under visible light irradiation with Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 being loaded by Pt, NiO or RuO2. The effect of Pt was better than that of NiO or RuO2 for improving the photocatalytic activity of Y2GaSbO7, Y2InSbO7 or Y2GdSbO7.