Exploring the Electronic Structure and Interfacial Phenomena of Pseudomorphic Rutile(110) Heterostructures: An Ab Initio Study

The photocatalytic application of pure TiO2 is limited because of its wide band gap, which restricts its activity only in the UV (ultraviolet) region of the solar spectrum. The high recombination of electron and hole charge carriers is another drawback to photocatalytic activity. In this work, we explore the electronic interfacial characteristics of pseudomorphic rutile(110) heterostructures, such as SnO2/TiO2, NbO2/TiO2, and MnO2/TiO2, using density functional theory (DFT)-based computations. The nature of the electronic structure and the band alignment are studied, which helps to identify the heterostructure. The internal electric field created at the interface of the heterostructure is crucial for defining the flow of electron and hole charge carriers, which is understood by the charge density difference plots. The enhancement of optical absorption of the heterostructure toward the visible region of the solar spectrum is further confirmed. From our analysis, we conclude that the nature of the electronic structure and band alignment of the rutile heterostructure are explored. Here, SnO2/TiO2 shows a type II heterostructure, MnO2/TiO2 shows a type I heterostructure, and NbO2/TiO2 shows a metal–semiconductor interface. From the heterostructure model, we proved that the band gap can be reduced toward the visible light absorption, and also, the electron and hole recombination can be avoided by generating the internal electric field along the interface of the heterostructure. From our analysis, we conclude that the pseudomorphic rutile(110) heterostructure will act as a potential photocatalyst for environmental pollution reduction.