Cationic–anionic mediated charge compensation on La2Ti2O7 for visible light photocatalysis

Abstract

The cationic–anionic mediated charge compensation effect was studied in the layered perovskite La₂Ti₂O₇ for the visible light photocatalysis. Our screened hybrid density functional study shows that the electronic structure of La₂Ti₂O₇ can be tuned by the cationic (V, Nb, Ta)/anionic (N) mono- and co-doping. Such mono-doping creates impurity states in the band gap which helps the electron–hole recombination. But if the charge compensation is made by the cationic–anionic mediated co-doping then such impurity states can be removed and can be a promising strategy for visible light photocatalysis. The absolute band edge position of the doped La₂Ti₂O₇ has been aligned with respect to the water oxidation/reduction potential. The calculated defect formation energy shows the stability of the co-doping system is improved due to the coulomb interactions and charge compensations effect.