Nb₂O₅/BiOCl composite as a visible-light-active photocatalyst for the removal of RhB dye and photoelectrochemical studies

In this work, BiOCl, 0.5%, 1%, and 5% Nb₂O₅/BiOCl (NBO/BCl) composite were prepared by a facile co-precipitation method. The synthesized materials were characterized using various characterization techniques such as XRD, FTIR, Raman, UV–Vis DRS, PL, BET, and TEM. The XRD confirms the formation of NBO/BCl composite with no impurities detected. The FT-IR results revealed the successful formation of the NBO/BCl composite, where both functional groups belonging to BiOCl and NBO/BCl were present. The TEM showed that BiOCl and 1% NBO/BCl have irregular nanoplate-like morphology with an average thickness of 22 and 18 nm, respectively. The photocatalytic degradation performance of the BiOCl and NBO/BCl composites was evaluated by degrading Rhodamine B (RhB) dye under visible light irradiation. Among all of the photocatalysts, 1% NBO/BCl showed the highest photocatalytic activity in which it degraded 96.7% of RhB dye in 120 min under visible light irradiation. Furthermore, the photoelectrochemical response of BiOCl and NBO/BCl composites was investigated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. The LSV and EIS analysis of NBO/BCl showed enhanced response when exposed to visible light compared to dark conditions. The significant improvement in the photocatalytic and photoelectrochemical performance of NBO/BCl composite was attributed to the synergistic effects of the NBO/BCl which enhanced light absorption abilities and charge carrier transfer making it easier for charge separation by lowering the recombination rate.