LaTaON2–BaTaO2N solid solutions for photocatalytic water oxidation

Solid solutions of LaTaON2 and BaTaO2N, i.e., La1−xBaxTaO1+yN2−y (0 ≤ x, y ≤ 1), have been investigated as visible-light-active photocatalysts for water oxidation reactions. A number of important parameters such as Ta–O/N distance, Ta–O/N–Ta angle, band gap and band edge alignments can be tailored by adjusting their solid solution levels, which in turn, effectively steer the photocatalytic behaviors. In particular, optimal photocatalytic activity for water oxidation can be achieved in the solid solution La0.2Ba0.8TaO1+yN2−y (x = 0.8), exhibiting an apparent quantum efficiency (AQE) as high as 3.91% at 420 ± 20 nm. This work signifies the usefulness of the solid solution strategy for ameliorating the photocatalytic properties of perovskite oxynitrides that can be well-extended to many other semiconductor photocatalysts.