First principles study of optical properties of Ni- and Pd-doped TiO2 as visible light catalyst

Doping TiO2 with noble metals, transition metals, cations, anions have yielded very promising results in enhancing photocatalytic activity of TiO2 in the visible region and its role in generating alternate forms of energy. Noble metals in general can effectively slow down carrier recombination. However, the study of Pd and Ni as dopant can lead to a reliable and versatile TiO2-modified photocatalyst. In this paper, we explore the optical properties of Pd- and Ni-doped TiO2 by doping with 4.17% Ni and Pd dopant concentrations. The optical properties prove that Ni-doped TiO2 can absorb well in the visible region with an absorption coefficient of 1 × 105 cm−1. Hence, Ni-doped TiO2 can successfully alter the electronic and optical properties of TiO2 for favorable future applications. In the visible region, absorption coefficient of Pd-doped TiO2 supercell is around 1.2 × 105 cm−1 which is comparatively greater than that of pure TiO2 confirming its utility as a versatile and viable visible light photocatalyst. The other optical properties like reflectivity, refractivity, extinction coefficient and electron energy loss spectrum have also been studied.