Structural and morphological optimization of Ni doped ZnO decorated silicon nanowires for photocatalytic degradation of methylene blue

Abstract

In the current work, nickel doped zinc oxide decorated silicon nanowires (SiNWs) were elaborated and applied for photocatalytic degradation of organic dyes. Nickel doped zinc oxide (Ni-ZnO) was synthesized via a facile sol-gel process of metal acetates by varying Ni content from 0 to 5% followed by the annealing process. As-prepared Ni-ZnO was subsequently spin-coated on to silicon nanowires to get ZnO-Ni/SiNWs nanohybrids. The effect of Ni doping on structural, morphological and photocatalytic properties of ZnO-Ni/SiNWs was investigated. Fourier Transform InfraRed spectroscopy (FTIR) analysis confirms the complete removal of organic moieties from as-prepared Ni-ZnO after annealing at 300˚ C. X-ray diffraction studies proved the presence of pure phase hexagonal wurtzite structure while showing a decrease of crystalline size with the increase in Ni dopant. Further, SEM and Raman mapping confirm homogeneous distribution of Ni-ZnO on Si nanowires. Photocatalysis studies showed that Ni doping enhances slightly the photocatalytic degradation of methylene blue. Highest degradation efficiency of 97% with best kinetic rate constant value was obtained for Ni-ZnO (5%)/SiNWs with hydrogen peroxide addition. The developed structure stands as promising candidates as efficient, cost-effective and reusable photocatalytic systems for organic dye decomposition.