Two-dimensional ultrathin metal-based nanosheets for photocatalytic CO conversion to solar fuels.

Artificially simulated photosynthesis has created substantial curiosity as the majority of efforts in this arena have been aimed to upsurge solar fuel efficiencies for commercialization. The layered inorganic 2D nanosheets offer considerably higher tunability of their chemical surface, physicochemical properties and catalytic activity. Despites the intrinsic advantages of such metal-based materials viz., metal oxides, transition metal dichalcogenides, metal oxyhalides, metal organic frameworks, layered double hydroxide, MXene's, boron nitride, black phosphorous and perovskites, studies on such systems are limited for applications in photocatalytic CO reduction. The role of metal-based layers for CO conversion and new strategies such as surface modifications, defect generation and heterojunctions to optimize their functionalities are discussed in this review. Research prospects and technical challenges for future developments of layered 2D metal-based nanomaterials are critically discussed.