Preparation of Zr-doped CaTiO3 with enhanced charge separation efficiency and photocatalytic activity

A series of Zr-doped CaTiO3 powders were prepared with the mild co-precipitation method and calcined at 850 °C for 3 h. The as-prepared Zr-doped CaTiO3 samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectra (XPS). XRD result revealed the presence of single perovskite phase of CaTiO3. UV–Vis diffusive reflection spectra of Zr-doped CaTiO3 indicated that the absorbance obviously increased in the visible light irradiation. XPS analysis showed that two types of oxygen existed on the photocatalyst surface, including lattice oxygen and absorbed oxygen. Their photocatalytic activity in the case of the degradation of methyl orange in water and photoelectrochemical activity were also tested. The 5%Zr-doped (mole fraction) CaTiO3 sample showed the highest photocatalytic activity. The enhanced photocatalytic activity was ascribed to the change of the lattice structure, existence of oxygen vacancies and increase of the photogenerated charge separation efficiency.