Preparation and optical properties of Te4+/V5+-stabilized δ-Bi2O3 for visible light-driven photocatalyst

Te4+ and V5+-codoped Bi2O3 nanoparticles were synthesized via the sol-gel method. The sample showed a loose aggregation with the ball-like nanoparticles (of 200-400 nm). X-ray powder diffraction (XRD) refinements were used to investigate the crystallinity formations. As-prepared Bi2-xTexVxO3 (x = 0.1, 0.2) samples present delta-Bi2O3 phase with space group of Fm-3m at room temperature. The results indicate that the cubic structure could be stabilized via Te4+ and V5+-codoping in Bi2O3 lattices. UV-vis absorption measurements concluded that Te4+/V5+-codoping could modify the band gap of delta-Bi2O3. Te/V-doped samples could harvest more visible light in longer-wavelength region. The improved photocatalysis of Bi2-xTexVxO3 (x = 0.1, 0.2) on RhB photodegradation was in presence with the irradiation of visible-light (lambda > 420 nm). To elucidate the photocatalytic mechanisms, XPS measurements, luminescence and lifetimes and impedance spectra were measured and analyzed. The improved photocatalysis was related with the microstructure changes and the multivalent V ions. (C) 2019 The Authors. Published by Elsevier Ltd.