Significance of Ni doping on structure-morphology-photoluminescence, optical and photocatalytic activity of CBD grown ZnO nanowires for opto-photocatalyst applications

Abstract

In this work, we study bare and Nickel (Ni) doped ZnO nanostructured thin films synthesized by the chemical bath approach. The as-prepared thin films were characterized extensively by XRD, SEM, PL, and UV–visible spectroscopy before and after Ni incorporation. Finally, the photocatalytic action of all catalysts was assessed using methylene blue (MB) dye degradation under the visible light irradiation. X-ray diffraction analysis approves wurtzite hexagonal structure with predominant orientation along (002) plane, and crystallite size was noticed to reduce from 34 to 32 nm by Ni-doping. The SEM images proved the formation of well-defined nanowire structures. Photoluminescence analysis confirmed the band-edge and defect-related emission peaks. The intensity of PL spectra ensured a decreased value after Ni-doping, suggesting delayed electron-hole pair recombination, which influences the decolorization activity. The 3 wt% Ni-doped ZnO thin film possessed the least optical bandgap value of 3.21 eV. It was observed that the Ni (3%) doped ZnO nanowires showed a significantly improved photocatalytic performance (96%) compared to the pure ZnO nanostructure (83%).