Self-supported porous Ni-Fe-P composite as an efficient electrocatalyst for hydrogen evolution reaction in both acidic and alkaline medium

摘要

Self-supported porous Ni-Fe-P nanocomposite cathode was fabricated via a direct reaction between metallic foam (Ni-Fe) and P vapor. Microstructure characterization results confirm that, after the reaction with P vapor, the metallic framework including Ni and Fe was converted into corresponding metallic phosphide compounds (i.e., Ni2P, Ni5P4 and Fe2P) and quantities of nanosheet arrays vertically-grown on the ligament. Both in acidic (0.5 M H2SO4) and alkaline (1.0 M KOH) media, the as-obtained Ni-Fe-P electrode demonstrates a quite high HER catalytic performance as compared with pristine Ni and Ni-Fe foam, even being almost close to state-of-the-art Pt/C. The as-evolved typical micro-nano hierarchical 3D integrated framework coupled with quantities of nanosheet arrays on it should be responsible for the great HER performance of this resulting composite cathode, which provides not only fast channels for electron transfer but also offers large electrochemical surface area so as to expose more active sites toward the electrocatalysis for HER. Meanwhile, the synergistic effect between the three active Ni2P, Ni5P4 and Fe2P phase may also play a crucial role in the as-revealed superior HER activity. These excellent results promise the potential application of this typical kind of multi-component Ni-Fe-P cathode toward electrochemical water splitting for large-scale hydrogen fuel production. (C) 2016 Elsevier Ltd. All rights reserved.