Preparation and characterization of direct Z-scheme photocatalyst Bi2O3/NaNbO3 and its reaction mechanism

• Published in: Applied surface science 2014-02, Vol.292, p.357-366
• Main Authors: Chen, Shifu, Hu, Yingfei, Ji, Lei, Jiang, Xiaoliang, Fu, Xianliang
• Format: Article
• Language: English
• Subjects: Activity; Bi2O3/NaNbO3; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diffraction; Diffusion; Electron paramagnetic resonance; Exact sciences and technology; Photocatalysis; Photocatalyst; Physics; Reaction mechanism; Reflection; Scanning electron microscopy; Transmission electron microscopy; X-ray photoelectron spectroscopy; X-rays; Z-scheme
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.11.144

•A highly active Bi2O3/NaNbO3 photocatalyst was prepared by a facile ball milling.•The results revealed that Bi2O3/NaNbO3 is characteristic of Z-scheme photocatalyst.•The rate constant of RhB for Bi2O3/NaNbO3 is 6.3 times that of pure NaNbO3.•The e− in the CB of Bi2O3 and h+ in the VB of NaNbO3 are quickly combined.•The e− in the CB of NaNbO3 and h+ in the VB of Bi2O3 produce •O2− and •OH, respectively. In this paper, highly active Bi2O3/NaNbO3 photocatalyst was prepared by a facile ball milling method using NaNbO3 and Bi2O3 as precursors. The photocatalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectra (XPS), and Brunauer–Emmett–Teller (BET) surface areas. The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine B (RhB). The results showed that the photodegradation rate of RhB for Bi2O3(5.0wt%)/NaNbO3 photocatalyst is 6.3 times that of pure NaNbO3. The optimum percentage of doped Bi2O3 is 5.0wt%. And the composite photocatalyst exhibits good stability. Based on the results of characterization by determining reactive species, terephthalic acid photoluminescence probing technique (TA-PL), and electron spin resonance (ESR) technology, it is proposed that the Bi2O3/NaNbO3 has the characteristic of direct Z-scheme type photocatalyst. The mechanism of increased photocatalytic activity was also discussed.