Photoinduced Charge Transfer Properties and Photocatalytic Activity in Bi2O3/BaTiO3 Composite Photocatalyst

A series of Bi2O3/BaTiO3 composite photocatalysts with different mass ratios of Bi2O3 vs BaTiO3 were prepared by an impregnating-annealing method. X-ray diffraction (XRD), high-resolution transmission electron microscopic (HRTEM), and UV-vis diffuse reflection spectroscopy (DRS) confirmed that Bi2O3 and BaTiO3 coexisted in the composites. The results of surface photovoltage (SPV) experiments showed enhancements of photovoltaic response in composites, which indicated a higher separation efficiency of photoinduced charges due to the establishment of an efficient interfacial electric field between Bi2O3 and BaTiO3 in the composites. The consistency of phtocatalytic activity and photovoltaic response intensity of photocatalysts showed that the efficiency interfacial electric field between Bi2O3 and BaTiO3 played an important role in improving the degradation efficiency of Rhodamine B (RhB). The 60%-Bi2O3/BaTiO3 sample with the best activity was found by optimizing the mass ratios of Bi2O3 vs. BaTiO3. On the basis of the work function (WF) measurements, a reasonable energy band diagram was proposed for BaTiO3/Bi2O3 composite. It would be helpful in designing and constructing high efficiency heterogeneous semiconductor photocatalyst.