Enhancing the Photocatalytic Performance of Anatase TiO2 through Vanadium, Mangenese and Nitrogen Co-doping: A DFT Study

Abstract

TiO₂ is a well-known photocatalyst with several potential applications. But because of its wider band gap, its optical activity is restricted to the UV region of the electromagnetic spectrum. These peak limits the photocatalytic activity of the specimen. To boost the photocatalytic activity of TiO₂, it is necessary to shift its absorption peak from the ultraviolet to the visible range by reducing its bandgap. Doping of several metals and non-metals is one of the strategies adopted to decrease the bandgap of TiO₂. This research article provides an overview of the effects of co-doping with Vanadium, Manganese, and Nitrogen on the structural and optoelectronic properties of anatase TiO₂ using the framework of Density Functional Theory (DFT). V–N/TiO₂, Mn–N/TiO₂, and Mn–V/TiO₂ were prepared, in which Mn and V were completely replaced at the i site, while N was at the O site. It was predicted that (V–N) doping in TiO₂ decrease the bandgap from 2.13eV to 1.66eV. This decrease occurred due to the newly generated electronic states, i.e. V–3d and N–2p, below the conduction band minimum and the valence band maximum, respectively. (Mn– N) and (Mn–V) co-doping in TiO₂ decrease the value of bandgap to 1.36eV and 1.22eV respectively. In these two models, the Fermi surface moved above the conduction band minimum, and thus, these models acted as N–type semiconductor. Co-doping also enhanced the optical performance of the specimen. It was observed that optical absorption increases as the model's bandgap energy decreases. The most enhanced optical absorption performance was predicted for Mn–V/TiO₂ due to the effective electron-hole pair recombination.