Dip-coating deposition of BiVO4/NiO p–n heterojunction thin film and efficiency for methylene blue degradation

Abstract

This paper deals with a simple FTO/p–n heterojunction electrode assembly formed by BiVO4 and NiO thin films, where the precursor solution is obtained by solution combustion synthesis and precipitation in aqueous media techniques, respectively, whereas the thin films were deposited by the dip-coating deposition process. The FTO/p–n electrodes are characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and UV–Vis spectroscopy. The performance analysis based on the methylene blue degradation reaction have shown that the p–n electrodes, FTO/p-NiO/n-BiVO4 and FTO/n-BiVO4/p-NiO have higher electroactivity under visible light irradiation condition when compared to single BiVO4 thin film, deposited separately, with estimated kobs value of 340 × 10−4 min−1, 270 × 10−4 min−1 and 150 × 10−4 min−1, respectively.