Ta3N5–LaTaON2 heterojunction with matched interfaces to accelerate charge separation for efficient photocatalytic water oxidation

Abstract

Charge separation is generally considered as the most critical step to achieve efficient photocatalytic reactions. Although charge separation can be promoted by a semiconductor heterojunction, its efficacy is inherently restrained by the mismatched atomic arrangements across the heterojunction interfaces. Here, Ta3N5–LaTaON2 heterojunction with matched interfaces has been fabricated by one-step ammonolysis treatment of KLaTa2O7. The match interfaces are formed by nearly perfect adhesion of Ta3N5 (010) and LaTaON2 (101¯) facets whose interatomic distance is similar. Compared with conventional heterojunction, the so-formed Ta3N5–LaTaON2 heterojunction are extremely efficient in accelerating charge separation which in turn enables a high photocatalytic activity. An apparent quantum efficiency as high as 11.6% at 420 ± 20 nm has been reached by Ta3N5–LaTaON2 heterojunction, which is almost three times higher than Ta3N5/LaTaON2 mixtures. These results signify the importance of matched heterojunction interfaces for charge separation and provide a paradigm in the design of efficient heterojunction-based semiconductor photocatalysts.