Effect of nickel doping concentration on the morphological and structural properties of titanium dioxide nanoparticles

Abstract

Titanium dioxide (TiO2) is widely used as a photocatalyst due to its advantages of low cost, photostability, strong oxidation capability, and high resistance to chemical and environmental sustainability. However, TiO2 has drawbacks of a wide band gap and fast recombination of electron-hole pairs which reduces its photocatalytic efficiency. Therefore, doping TiO2 with metal ions can be considered to overcome these issues. In this study, Ni-doped TiO2 with different doping concentrations (1, 3, 5, and 7 wt%) have been successfully prepared by the sol-gel method. All samples were characterized using field emissions scanning electron microscopy (FESEM), Energy dispersion X-ray (EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). The surface morphology of all samples examined by FESEM showed an agglomeration of spherical shape. In addition, EDX confirms the presence of Ti and O atoms in undoped TiO2 sample and the presence of Ni atoms in Ni-doped TiO2 samples. XRD analysis showed the structural phase of anatase was observed in all samples. The crystallite size of TiO2 decreased significantly from 16.058 nm to 14.926 nm when it was doped with 5 wt% of Ni. The specific surface area (SSA) is indirectly proportional to the crystallite size with the highest value of SSA found to be 95.032 m2.g−1 for 5wt% Ni doping. FTIR presents Ti-O-Ti and OH bonds with a small shift to higher wavenumbers. These results indicated that Ni has significant influences on the morphological and structural properties of TiO2 with the optimum doping concentration of 5 wt%.