Solar light driven degradation of post tanning water at heterostructured BiVO4-ZnO mixed oxide catalyst interface

Heterostructured mixed oxide BiVO4-ZnO is used as semiconductive photocatalyst for the degradation of simulated wastewater from tannery industry in the presence of sun light at neutral pH by semiconductive photocatalysis. The mixed oxide catalyst showed higher degrading efficiency in comparison to bare ZnO and bare BiVO4 metal oxides. Analysis of FESEM and AFM images reveals that particles are in the range of 40 nm and mixed oxide catalyst exhibit uniform porous structure respectively. The crystallinity and planes of the catalysts were studied by XRD analysis. The optical band gap of the mixed oxide catalyst (3.02 eV) was examination by UV-Vis diffuse reflectance spectroscopy. The higher catalytic activity with BiVO4-ZnO is attributed to the change in charge carrier equilibrium at the interface of mixed oxide catalyst, which in turn reduces the recombination rate of electron hole pairs and also decreases the energy gap suitable for degradation in solar light. Under the optimal experimental conditions, 64% reduction in COD has been observed with heterostructured BiVO4-ZnO catalyst in six hours of reaction in the presence of sun light.