Rationally designed transition metal hydroxide nanosheet arrays on graphene for artificial CO₂ reduction

The performance of transition metal hydroxides, as cocatalysts for CO₂ photoreduction, is significantly limited by their inherent weaknesses of poor conductivity and stacked structure. Herein, we report the rational assembly of a series of transition metal hydroxides on graphene to act as a cocatalyst ensemble for efficient CO₂ photoreduction. In particular, with the Ru-dye as visible light photosensitizer, hierarchical Ni(OH)₂ nanosheet arrays-graphene (Ni(OH)₂-GR) composites exhibit superior photoactivity and selectivity, which remarkably surpass other counterparts and most of analogous hybrid photocatalyst system. The origin of such superior performance of Ni(OH)₂-GR is attributed to its appropriate synergy on the enhanced adsorption of CO₂, increased active sites for CO₂ reduction and improved charge carriers separation/transfer. This work is anticipated to spur rationally designing efficient earth-abundant transition metal hydroxides-based cocatalysts on graphene and other two-dimension platforms for artificial reduction of CO₂ to solar chemicals and fuels.