Phosphorus-doped Fe3O4 nanoflowers grown on 3D porous graphene for robust pH-Universal hydrogen evolution reaction

It is extremely necessary to develop highly efficient and low-cost non-noble metal electrocatalysts for hydrogen evolution reaction (HER) under a pH-universal condition in the realm of sustainable energy. Herein, we have successfully prepared phosphorus doped Fe3O4 nanoflowers on three-dimensional porous graphene (denoted as P-Fe3O4@3DG) via a simple hydrothermal and low-temperature phosphating reaction. The P-Fe3O4@3DG hybrid composite not only demonstrates superior performance for HER in 1.0 M KOH with low overpotential (123 mV at 10 mA/cm(2)), small Tafel slope (65 mV/dec), and outstanding durability exceeding 50 h, but also exhibits satisfying performances under neutral and acidic medium as well. The 3D graphene foam with large porosity, high conductivity, and robust skeleton conduces to more active sites, and faster electron and ion transportation. The phosphorus dopant provides low Gibbs free energy and ability of binging H+. The synergistic effect of 3DG substrate and P-Fe3O4 active material both accelerates the catalytic activity of Fe-based hybrid composite for HER. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.