Prediction of semiconductor band edge positions in aqueous environments from first principles

The ability to predict a semiconductor's band edge positions in solution is important for the design of water-splitting photocatalyst materials. In this paper, we introduce a first-principles method to compute the conduction-band minima of semiconductors relative to the water H₂O/H₂ level using density functional theory with semilocal functionals and classical molecular dynamics. We test the method on six well known photocatalyst materials: TiO₂, WO₃, CdS, ZnSe, GaAs, and GaP. The predicted band edge positions are within 0.34 eV of the experimental data, with a mean absolute error of 0.19 eV.