Iron Doping Effect for Oxygen Evolution Hybrid Catalysts based on Nickel Phosphate/Nitrogen-Doped Carbon Nanoflakes

Developing highly efficient and earth-abundant oxygen evolution reaction (OER) electrocatalysts is of great significance for sustainable energy conversion technologies. Herein, a facile thermal transformation strategy was developed to synthesize nickel iron phosphate nanoparticles incorporated in N-doped carbon (NiFeP/N-C) nanoflakes as highly efficient OER electrocatalysts based on a metal organophosphonate precursor. The amino trismethylene phosphonic acid ligand used here has excellent affinity toward various metals and thus can act as a P, C, and N source on a molecular scale, which simplifies the synthesis of conductive material-supported multi-metal phosphates. Benefiting from the derived N-doped carbon and the synergistic effect of bimetal ions, the sample denoted NiFeP/N-C-700 exhibits outstanding electrocatalytic activity. It exhibits a lower overpotential of 280 mV, a small Tafel slope of 48 mV dec(-1) at a current density of 10 mA/cm(2), and superior stability in 1 M KOH solution.