Metal-Cluster-Directed Surface Charge Manipulation of Two-Dimensional Nanomaterials for Efficient Urea Electrocatalytic Conversion

Metal clusters represent a category of functional materials of vital importance for many applications. In this work, we show a useful function of metal clusters, which can contribute to adjusting the surface charges of two-dimensional (2D) nanomaterials in aqueous solution. We develop a strategy to manipulate the surface charges of 2D C3N4 nanosheets continuously from negative to positive by decoration with only a small fraction of cobalt clusters (<5 wt %). Mechanism study reveals the strong interactions between cobalt atoms and nitrogen of 2D C3N4 can promote the charge transfer between them, which consequently alters overall charge negativity of hybrid systems. Further, by exemplifying with urea oxidation reaction, the surface charge effect of 2D Co–C3N4 nanosheets over electrocatalytic process has been investigated, and cationic Co–C3N4-based electrodes exhibit superior electrocatalytic performances with high activity, favorable kinetics, and strong durability.