Oriented ZnmIn2Sm+3@In2S3 heterojunction with hierarchical structure for efficient photocatalytic hydrogen evolution

It remains a great challenge to design and prepare highly efficient semiconductor-based photocatalysts for water splitting. To achieve this goal, the design of oriented heterojunctions for efficient carrier transport and separation is a new strategy based on their conductive anisotropy. Herein, a novel oriented J-J type ZnmIn2Sm+3@In2S3 heterojunction photocatalyst with hierarchical structures is fabricated with the assistance of oxalic acid. The hierarchical structures consist of 'flower-like' hollow ZnmIn2Sm+3 microspheres with epitaxially grown quantum confined In2S3 along the petal rims (J-J type heterojunction). This heterojunction improves the transport and separation of the photoexcited carriers, and extends the visible-light response range. Thus, the heterojunction photocatalyst exhibits significantly enhanced photocatalytic activity with a hydrogen evolution rate of 330 μmol h−1, which is about 4 times higher than that of single ZnIn2S4. The findings provide new insights to construct efficient oriented heterojunctions for anisotropic semiconductors.