Enhanced photocatalytic dye degradation and hydrogen evolution performance of Cu encapsulated BiVO4 under visible light irradiation

Abstract

Monoclinic Bismuth Vanadate (BiVO4) has recently attracted a lot of interest for being one of the most effective photocatalyst materials for waste water treatment and it could also capture a wide spectrum of visible light. In this study, Sol Gel dip coating procedures were used to fabricate BiVO4 thin films encapsulated with Cu at various concentrations (1, 2, 3, and 4 wt%) and used as the photocatalysts, and a number of analytical techniques were employed to determine the films' physiochemical properties. The monoclinic BiVO4 crystalline structure was identified using XRD and Raman spectroscopy. FESEM images indicate that the morphology changes from amorphous to a nano flake like structure when Cu is encapsulated with BiVO4, and improved BET surface area was observed for BiVO4 thin films with increasing Cu concentration. The electronic structure was described using XPS, and optical absorption investigations revealed that the red shift within the absorption edge, which shows the band gap energy, was reduced for Cu-encapsulated BiVO4, allowing successful photogeneration and hydrogen (H2) evolution under visible light. The photocatalytic activity of BiVO4:Cu was investigated using the decomposition of Methylene blue (MB) dye under visible light. This investigation demonstrated that MB dye completely degrades within 120 min. It has been shown that BiVO4:Cu (4 wt%) thin films had higher degradation efficiencies with first order kinetics. This Cu-encapsulated BiVO4 monoclinic and nanoflake structure demonstrated strong optical absorption, improved charge carrier transport abilities, and high penetration depth, as well as maximum photodegradation efficiency and H2 evolution.

Keywords

• BiVO4
• Sol Gel
• Monoclinic
• Methylene blue
• Photocatalytic activity
• Hydrogen evolution