Ultrathin 2D type-II p-n heterojunctions La2Ti2O7/In2S3 with efficient charge separations and photocatalytic hydrogen evolution under visible light illumination

In this work, novel 2D type-II p-n heterojunctions La 2 Ti 2 O 7 /In 2 S 3 have been fabricated. The heterojunctions exhibit much improved photocatalytic activity over individual moieties and their physical mixtures in which 18-fold increment in hydrogen production has been achieved under visible light illumination (λ ≥ 400 nm). Their superior activities stem from intimate face-to-face contact between La 2 Ti 2 O 7 and In 2 S 3 in the heterojunctions which guarantee facile charge interchange. Photoelectrochemical analysis suggests that efficient charge separations occur at the interfaces of the heterojunctions and contributes to a prolonged charge lifetime as well as the much enhanced photocatalytic activities. Such a simple strategy by fabricating ultrathin type-II p-n heterojunctions also warrant promising applications in other areas such as optoelectronics, sensors etc. whereby efficient charge separations are needed.