Composite materials made by two units in intimate contact are widespread in materials science applications, such as photocatalysis, solar cells, and sensors. Their major advantage is represented by the possibility to hinder the charge carriers’ recombination process, provided that their alignment of the band edges is favorable. Among all, oxide-oxide interfaces have been widely applied in photo-catalysis experiments, including water splitting and pollutants degradation. Computational studies may provide insights at the atomist level on the nature, structure, and electronic properties of interfaces, that can complement the information arising from experimental techniques. Here, we present a computational overview of our recent studies on interfaces, focusing on virtues and criticalities of the approach based on Density Functional Theory (DFT) at the level of hybrid functionals. We will discuss the different amount of information that one can access from first principles, such as the structure of an interface, its stability and energetics, and important electronic properties as band edges alignment, charge separation and interface polarization. We will show that the combination of all of these aspects is responsible of the overall properties of devices. We will focus on established heterojunctions, such as BiVO4/WO3 and surface junctions such as TiO2/TiO2, showing that the interface promotes the charge separation, and its formation can be explained in the light of energetically favorable matching of surfaces’ terminations. Last, we discuss the crucial role of the interface polarization in a direct Z-scheme photocatalyst, the C3N4/TiO2 interface, driving the favorable path for carriers’ separation.

Rational design of semiconductor interfaces for photocatalysis and photoelectrocatalysis

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.