First Principles Study of TiO2 as Visible Light Catalyst with Ni Doping

Abstract

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. However, the study of Ni as a dopant can lead to a reliable and versatile TiO2 modified photocatalyst, as Ni is an earth-abundant metal. In this paper we explore the electronic properties of Ni doped TiO2 by varying the Ni dopant concentrations. As Ni doping increase from 4.17% to 8.33% to 12.5%, we observe Ni 3d orbitals being introduced into TiO2 bandgap in the forbidden region and the hybridized orbitals of Ti 3d and Ni 3d extending well over the conduction band region near Fermi level indicating an increased metallic nature and hence conduction. The charge density plots confirm a metallic bond being developed as Ni concentration increases. 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 favourable future applications.