Vanadium doping of strontium germanate and their visible photocatalytic properties

Vanadium-doped strontium germanate with rod-shaped morphology and different vanadium contents has been synthesized by a facile hydrothermal process. The obtained vanadium-doped strontium germanate has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet (UV) diffuse reflectance spectra. The phase of the vanadium-doped strontium germanate depends on the vanadium content. SEM observations show that the vanadium-doped strontium germanate comprises a rod-shaped morphology with diameter and length of nanoscale/microscale size and longer than 10 mm, respectively. The band gap of the vanadium-doped strontium germanate depends on the vanadium content and increases significantly from 2.74 eV to 3.02 eV with the vanadium content increasing from 1 wt% to 10 wt%. Vanadium-doped strontium germanate shows highly efficient photocatalytic activity for the degradation of methylene blue under sunlight irradiation. The results show that vanadium-doped strontium germanate is very promising for visible-light photocatalytic applications.