Effect of FeWO4 doping on the photocatalytic activity of ZnO under visible light irradiation

FeWO4/ZnO photocatalyst has been prepared by simple co-precipitation method and characterized using UV-vis diffuse reflectance spectroscopy (UV-vis-DRS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) techniques and Brunauer-Emmett-Teller (BET) techniques. The XRD results showed that the average particle size of ZnO, FeWO4 and FeWO4/ZnO were found to be 31.17 nm, 63.53 nm and 22.59 nm respectively. The prepared photocatalyst composed of rod and plate with little agglomeration is seen from SEM result. The specific surface area of the as prepared FeWO4/ZnO photocatalyst was estimated to be 31.3379 m2/g. The photocatalyst can degrade methylene blue (MB), an azo dye extensively used in textile and paper industries in water under visible light irradiation. The effect of various parameters such as irradiation time, initial dye concentration, pH and catalyst concentration has been investigated in detail. FeWO4/ZnO photocatalyst (0.04 g/L) in the molar ratio of 1:0.5 calcination at 500 °C can effectively degrade about 96% of (20 μm) MB at a pH of about 10 by 180 min illumination in visible light. In all the degradation studies the reaction follows first order kinetics.