Incorporation of Pb2+, Fe2+ and Cd2+ ions in ZnO nanocatalyst for photocatalytic activity

In the present study, Pb-ZnO, Fe-ZnO, Cd-ZnO and Pb-Fe-Cd-ZnO nanoparticles were synthesized by the sonochemical method and those structural and optical properties were investigated by Fourier Transform Infrared spectroscopy (FTIR), UV-Vis spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD). Average crystallite size obtained was 60 nm. Moreover, the direct band gap has been calculated using Tauc's approach. Compared with pure ZnO, the band gap of the doped-ZnO NPs is smaller and it depends on the type of dopants. In addition, photocatalytic activity of all samples has been investigated by the degradation of congo red (CR) dye under UV irradiation in an aqueous medium. In the presence of ZnO NPs photocatalytic degradation of 35% was obtained for 180 min. But Pb-ZnO, Fe-ZnO, Cd-ZnO and Pb-Fe- Cd-ZnO have shown the degradation of 45, 57, 65 and 80% respectively; they have the faster decolorization as compared with the ZnO NPs. Moreover, the photocatalyst could be reused for five times without remarkable loss of its activity.