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

摘要

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.