Predicting the suitability of photocatalysts for water splitting using Koopmans spectral functionals: The case of TiO$_2$ polymorphs

TL;DR

This paper demonstrates that Koopmans spectral functionals can accurately predict the electronic properties of TiO2 polymorphs, aiding the assessment of photocatalysts for water splitting with a computationally efficient method.

Contribution

The study introduces a workflow using Koopmans spectral functionals to predict band structures of TiO2 polymorphs, improving accuracy and efficiency over previous methods.

Findings

Koopmans spectral functionals accurately predict TiO2 band structures.

The workflow requires only DFT and Koopmans calculations of bulk and interface.

Method shows promise for screening new photocatalyst materials.

Abstract

Photocatalytic water splitting has attracted considerable attention for renewable energy production. Since the first reported photocatalytic water splitting by titanium dioxide, this material remains one of the most promising photocatalysts, due to its suitable band gap and band-edge positions. However, predicting both of these properties is a challenging task for existing computational methods. Here we show how Koopmans spectral functionals can accurately predict the band structure and level alignment of rutile, anatase, and brookite TiO$_2$ using a computationally efficient workflow that only requires (a) a DFT calculation of the photocatalyst/vacuum interface and (b) a Koopmans spectral functional calculation of the bulk photocatalyst. The success of this approach for TiO$_2$ suggests that this strategy could be deployed for assessing the suitability of novel photocatalyst candidates.