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

Abstract

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.