Effect of nickel doping on the optical property and photocatalytic activity of titanium dioxide nanoparticles

Titanium dioxide (TiO₂) nanoparticles doped with various amounts of nickel were synthesised via a sol-gel method using titanium isopropoxide and nickel nitrate hexahydrate as precursors. The structural characterisation of the nanoparticles were performed by X-ray diffraction and transmission electron microscopy. Energy dispersive X-ray and X-ray photoelectron spectroscopy analyses confirmed the incorporation of nickel ions into the TiO₂ lattice. A remarkable red shift of the absorption edge was achieved by increasing the nickel content. Photoluminescence spectra indicated the quenching of emission intensity on doping. The feasibility of the photocatalytic degradation of bromophenol blue under visible light illumination was studied. The results showed that the catalytic activity is markedly increased by doping nickel ions.