Synthesis and photocatalytic properties of InVO_4 sol containing nanocrystals by mild hydrothermal processing

The precursor precipitation of InVO4 was synthesized by co-precipitation using indium trichloride (InCl3), ammonium metavanadate (NH4VO3) and ammonia (NH3·H2O) as raw materials. The InVO4 sols with orthorhombic phase were obtained by hydrothermal treatment (the precursor precipitation solution at 423 K, for 4 h). The precursor and sol of InVO4 were characterized by X-ray diffraction (XRD), Fourier Transform Infra-red spectra (FT-IR), scanning electron microscopy (SEM) measurements. The XRD patterns indicate that the InVO4 precursor is amorphous phase, InVO4 sol contains orthorhombic InVO4 nanocrystals. The results also reveal that the pH value of the reaction mixture and reaction temperature play important roles to the target phase. InVO4-TiO2 thin films on glass slides were prepared by the dip-coating method from the composite sol. The photocatalytic properties of the InVO4-TiO2 thin films were investigated by the photocatalytic degradation of methyl orange solution. The results indicate that it has better photocatalytic activities than pure TiO2 thin films or pure InVO4 thin films with UV light.