Calcium germanate nanowires by vanadium doping with improved photocatalytic activity

Abstract

Vanadium-doped calcium germanate nanowires were prepared by a simple hydrothermal method.The samples were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and solid UVVis diffuse reflectance spectrum.The photocatalytic activity of the vanadium-doped calcium germanate nanowires was investigated by the degradation of methylene blue (MB) under solar light irradiation.The results show that the vanadium-doped calcium germanate nanowires are composed of rhombohedral Ca 3 GeO 5 and orthorhombic CaV 3 O 7 phases.The nanowires have the diameter and length of 50200 nm and several dozens of micrometres, respectively.The band gap of the vanadium-doped calcium germanate nanowires strongly depends on the vanadium doping mass percentage.The absorption spectrum can be broadened to visible light region.The photocatalytic activity of the vanadium-doped calcium germanate nanowires is remarkably improved.Vanadium-doped calcium germanate nanowires with the vanadium doping mass percentage of 10% have the highest photocatalytic activity for MB degradation under solar light irradiation.