Prediction of (TiO2)x(Cu2O)y alloys for efficient photoelectrochemical water splitting†
Abstract
The formation of (TiO2)x(Cu2O)y solid-solutions is investigated using a global optimization evolutionary algorithm. First-principles calculations based on density functional theory are then used to gain insight into the electronic properties of these alloys. We find that: (i) Ti and Cu in (TiO2)x(Cu2O)y alloys have similar local environments as in bulk TiO2 and Cu2O except for (TiO2)(Cu2O) which has some trigonal-planar Cu ions. (ii) The predicted optical band gaps are around 2.1 eV (590 nm), thus having much better performance in the absorption of visible light compared with both binary