Hydrothermal synthesis of C doped ZnO nanoparticles coupled with BiVO4 and their photocatalytic performance under the visible light irradiation

Abstract

For the first time, C-ZnO/BiVO4 heterostructured nanocomposite has been synthesized from BiVO4 and carbon-doped ZnO nanoparticles. X-ray diffraction (XRD) study showed themonoclinic scheelite structure of BiVO4 and the hexagonal wurtzite structure of ZnO in the C-ZnO/BiVO4 composite. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images revealed the spherical nanoparticles of size 20 to 30 nm for C-ZnO. The band gap of the ZnO has turned towards the visible region by doping with carbon as well as a composite formation with visible light active material BiVO4. The chemical states of Zn, O, C and Zn, O, C, Bi, V species in C-ZnO, and C-ZnO/BiVO4 composite respectively were confirmed by X-ray photoelectron microscopy (XPS) analysis. Also, the XPS spectra showed the significant peaks shift in the electronic states of Zn, O, and C for the heterojunction composite. The suppression of the electron-hole recombination rate was confirmed from the quenching of photoluminescence (PL) intensity for the composite. The adsorption study has performed, and the experimental results fit well with the Langmuir isotherm model for understanding the catalytic activity of the samples. The possible Z-scheme photocatalytic mechanism of the C-ZnO/BiVO4 nanocomposite photocatalyst has proposed. The nanocomposite exhibited the enhanced catalytic activity with the higher degradation rate constant of 0.050 min−1 for 50 min irradiation of visible light compared with their counterparts.