A series of Zr-doped CaTiO3 powders were prepared with the mild co-precipitation method and calcined at 850℃ 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.
Perovskite ZnTiO3 was prepared through a new method which contained a hydrothermal process for the preparation of titanate nanotubes and an ion-exchange process.The titanate nanotubes were inferred to be H2Ti3O7·3H2O.X-ray diffraction（XRD）result revealed the presence of cubic perovskite phase of ZnTiO3.The unique chain-like morphology of ZnTiO3 was observed by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.UV-Vis diffusive reflection spectra of ZnTiO3indicated that the absorbance obviously increased in the visible light region.The degradation rate of methyl orange solution（15 mg/L）reached 95.3%over ZnTiO3（0.3 g/L） after 20 min xenon light irradiation,which was higher than that using the commercial catalyst P25 under the same reaction condition.The degradation kinetic results follow the first-order equation and the rate constant is 0.1020.
