New Insights into Layered Graphene Materials as Substrates to Regulate Synthesis of Ni-P Nanomaterials for Electrocatalytic Oxidation of Methanol and Water

The doping ring-core nickel phosphide/ graphene nanomaterial is obtained by H-2 reduction of the flower-like nickel phosphates/graphene oxide (NiPOGO) and sea urchin-like nickel phosphates/chemically converted graphene (NiPOG) substrates. The obtained structure of nickel phosphates depends on the influence of different kinds of oxygen-containing groups on the graphene substrate. The substrate can also affect the particle size and distribution of nickel phosphate nanoparticles. The substrate can adjust the particle size, distribution, and exposed growth direction of nickel phosphide. These materials with high activity are employed as electrochemical catalysts for methanol oxidation reactions, which is similar to 7 times that of pure nickel phosphide, and there is a very small Tafel slope of 47 mV decade(-1) in the water oxidation reaction. Our results highlight that the substrate structure is essential to catalytic materials for electrochemical oxidation of methanol and water.