Photophysical and photocatalytic properties of InMO4 (M = Nb5+, Ta5+) under visible light irradiation

Abstract A new class of solid photocatalysts, InTaO 4 and InNbO 4 , were prepared by the solid-state reaction. The powder X-ray diffraction and Rietveld structure refinement show that these compounds crystallize in the same crystal structure: wolframite type, monoclinic with space group P2/c. However, the octahedral TaO 6 in InTaO 4 slightly expands from that of NbO 6 in InNbO 4 , leading to the longer lattice parameters in InTaO 4 . The photocatalytic H 2 evolutions were obtained from pure water by the NiO x promoted InTaO 4 and InNbO 4 under visible light irradiation. The band gaps of InTaO 4 and InNbO 4 were estimated to be 2.6 and 2.5 eV, showing that the photocatalysts have ability to respond the wavelength of visible light region.