2D inorganic nanosheet-based hybrid photocatalysts: Design, applications, and perspectives

Highly anisotropic 2D nanosheets of inorganic solids with nanometer-level thickness attract a great deal of research activity because of their unique merits in exploring novel high performance photocatalysts applicable for environmental purification and production of renewable clean energy. The 2D inorganic nanosheets possess many valuable properties such as tailorable band structures and chemical compositions, large surface areas, well-defined defect-free surface structure, and tunable electrical conductivities. Due to these unique advantages of 2D inorganic nanosheets, these materials can be used as promising building blocks for hybrid-type photocatalysts with optimized band structures, expanded surface areas, improved charge separation behaviors, and enhanced reaction kinetics. Of prime importance is that unusually strong electronic coupling can occur between very thin 2D inorganic nanosheets and hybridized nanospecies, leading to the synergistic optimization of electronic and optical properties, and thus the remarkable enhancement of photocatalytic activity. Depending on the type of component nanosheets, diverse examples of inorganic nanosheet-based photocatalysts are presented along with the in-depth discussion about critical roles of inorganic nanosheet in these hybrid photocatalysts. Future perspectives in the researches for 2D inorganic nanosheet-based photocatalysts are discussed to offer useful directions for designing and synthesizing novel high performance photocatalysts applicable for renewable energy production and environmental purification.