Type-II ternary Bi 2 WO 6 /rGO/SnFe 2 O 4 heterojunction nanocomposites and their photocatalytic efficiency towards 4-nitrophenol reduction.

In this study, tin ferrite (SnFe 2 O 4 -spinel) and bismuth tungstate (Bi 2 WO 6 ) encapsulated on reduced graphene oxide (rGO) were synthesised using the hydrothermal method. This heterostructure nanocomposite was characterised using Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-Vis), powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), FT-Raman Spectroscopy (FT-Raman) and X-ray photoelectron spectroscopy (XPS) methods. The powder XRD results showed an increase in lattice parameters and a decrease in size when SnFe 2 O 4 and Bi 2 WO 6 were encapsulated on rGO. The catalytic activity of the type-II ternary Bi 2 WO 6 /rGO/SnFe 2 O 4 heterojunction nanocomposite was checked using a model reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH 4 as the reducing agent under light exposure. Bi 2 WO 6 /rGO/SnFe 2 O 4 showed better catalytic efficiency than the individual components like SnFe 2 O 4 , rGO/SnFe 2 O 4 , Bi 2 WO 6 , rGO/Bi 2 WO 6 and Bi 2 WO 6 /SnFe 2 O 4 nanocomposites. Thus, the type-II ternary Bi 2 WO 6 /rGO/SnFe 2 O 4 heterojunction nanocatalyst with better surface area and lower surface energy could be considered as a promising UV-light sensitive catalyst for the detoxification of various environmental pollutants and for other environmental remediations.