Catalytic mechanism of graphene-nickel interface dipole layer for binder free electrochemical sensor applications

The combination of graphene with metal nanoparticles can produce enhanced catalytic properties because of synergistic effects, and has been used to develop highly active catalysts for different applications. However, the mechanism of the synergistic effect between graphene and metal is poorly understood. Here we demonstrate that graphene-coated nickel foam shows a significant catalytic effect on electrodeless metal (gold, platinum, silver, and copper) deposition without any external reducing agent. This is attributed to the formation of an interface dipole layer, induced by the interaction between graphene and nickel. The interface dipole layer catalytic mechanism accelerates metal reduction reaction and explains the simultaneous formation of nickel hydroxide. The nickel hydroxide-wrapped silver hybrid self-assembly developed on the graphene-coated nickel foam serves as an efficient binder-free electrochemical sensor owing to its hierarchical structure.