Two-dimensional layered nanomaterials for visible-light-driven photocatalytic water splitting

Two-dimensional (2D) layered nanomaterials have trigged intensive interest in the photocatalytic field due to their intriguing physicochemical properties, which offer the possibility to develop highly-efficient visible-light-driven photocatalysts. In this review, we first discuss the historical developments of 2D nanomaterials, and outline their advantages as the building blocks to construct photocatalysts. Then, we summarize the typical synthesis methods, electronic and optical properties, and the corresponding influences on photocatalytic activity. Then, we in detail discuss some strategies for improving their photocatalytic activity by the modification or surface functionalization of 2D layered nanomaterial photocatalysts. Further, we highlight the applications of some typical 2D layered nanomaterials, including the graphene family, graphitic carbon nitride, transition metal dichalcogenides, and oxides for water splitting under the visible light illumination. Finally, we provide some personal perspectives on future challenges and opportunities in utilizing 2D layered nanomaterials for large-scale photocatalysis applications.