Enhanced photocatalytic ability of CuO/Ni-doped TiO2 nanocomposite under visible light: Theory and experiment

Abstract

CuO/Ni-doped TiO₂ composite photocatalysts were synthesized using a co-precipitation method as the composite of Ni-doped TiO₂ (Ni–TiO₂) with 0.5, 1.0, and 1.5 mol% of CuO. Composites with different CuO/Ni–TiO₂ ratios were studied to assess the influence of Ni and CuO on the crystal and local structure by X-ray diffraction (XRD) and X-ray absorption (XAS). The energy bandgap is investigated by UV–visible spectroscopy and is described by computational calculations using density functional theory (DFT). The correlation between the local site of Ni and the band structure will be analyzed and discussed by comparing the experiment and First-principle calculations. The photocatalytic activity of the CuO/Ni–TiO₂ systems is due to the absorption of radiation in the visible light region. The results indicated that 1.5 mol% of CuO contributes to the Ni–TiO₂ nanoparticles showing highest photocatalytic activity with rate constant of 0.03477 min⁻¹ in the degradation of Rhodamine B, which could be attributed to the low recombination rate of the electron-hole pair, and decrease of the bandgap, increase in the concentration of •OH radicals in the solution, which is beneficial for improving the photo degradation rate of organic compounds.