Photocatalytic Water Splitting for Hydrogen Production with Novel Y(2)MSbO(7) (M = Ga, In, Gd) under Visible Light Irradiation

Novel photocatalysts Y(2)MSbO(7) (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 Y(2)MSbO(7) (M = Ga, In, Gd) was reported. The results showed that Y(2)GaSbO(7), Y(2)InSbO(7) and Y(2)GdSbO(7) crystallized with the pyrochlore-type structure, cubic crystal system, and space group Fd3m. The lattice parameter for Y(2)GaSbO(7) was 10.17981 Å. The lattice parameter for Y(2)InSbO(7) was 10.43213 Å. The lattice parameter for Y(2)GdSbO(7) was 10.50704 Å. The band gap of Y(2)GaSbO(7) was estimated to be 2.245 eV. The band gap of Y(2)InSbO(7) was 2.618 eV. The band gap of Y(2)GdSbO(7) was 2.437 eV. For the photocatalytic water-splitting reaction, H(2) or O(2) evolution was observed from pure water with Y(2)GaSbO(7), Y(2)InSbO(7) or Y(2)GdSbO(7) as catalyst under visible light irradiation. (Wavelength > 420 nm). Furthermore, H(2) and O(2) were also evolved by using Y(2)GaSbO(7), Y(2)InSbO(7) or Y(2)GdSbO(7) as a catalyst from CH(3)OH/H(2)O and AgNO(3)/H(2)O solutions, respectively, under visible light irradiation (λ > 420 nm). Y(2)GaSbO(7) showed the highest activity compared with Y(2)InSbO(7) or Y(2)GdSbO(7). At the same time, Y(2)InSbO(7) showed higher activity compared with Y(2)GdSbO(7). The photocatalytic activities were further improved under visible light irradiation with Y(2)GaSbO(7), Y(2)InSbO(7) or Y(2)GdSbO(7) being loaded by Pt, NiO or RuO(2). The effect of Pt was better than that of NiO or RuO(2) for improving the photocatalytic activity of Y(2)GaSbO(7), Y(2)InSbO(7) or Y(2)GdSbO(7).