Hierarchically Heterostructured Ni(OH)₂/Fe–Ni₂P Nanoarray: A Synergistic Electrocatalyst for Accelerating Alkaline Hydrogen Evolution

Abstract

Developing high-performance electrocatalysts to accelerate hydrogen evolution reaction (HER) kinetics during alkaline water electrolysis is crucial for future hydrogen economy. Herein, we demonstrate a hierarchically heterostructured Ni(OH)2/Fe–Ni2P electrocatalyst to break through the limitation of the rate-determined water dissociation step, which remarkably reduces the activation energy (E a) from 14.29 to 11.30 kJ mol–1. The Ni(OH)2/Fe–Ni2P experimentally exhibits enhanced catalytic activity toward alkaline HER with supersmall overpotentials of 45 and 134 mV to realize 10 and 100 mA cm–2, respectively. Furthermore, it shows a superior electrochemical stability for continuously operating over 96 h under 100 mA cm–2, thus surpassing most reported phosphide-based catalysts. The customized heterointerface engineering has been proposed to be responsible for the electron structure optimization of Ni(OH)2/Fe–Ni2P, which simultaneously improves its H2O adsorption/dissociation and H* adsorption capacities for realizing high-efficient synergistic catalysis. This finding expands the application of interfacial design in exploring highly active electrocatalysts for alkaline water splitting.

Heterogeneous bimetallic Ni(OH)2-NiMoO4/NF as an efficient HER electrocatalyst for alkaline water splitting

“…19 Ni(OH) 2 is not observed in XRD due to the thin weak crystalline state of Ni(OH) 2 . 20,21 The morphology and structure of the as-synthesized product were characterized by SEM. Aer hydrothermal and calcination treatments, the NiMoO 4 nanorods (width = 500 nm) with high density are homogeneously distributed on the NF surface and separated from each other (Fig.…”

Review—Recent Advances in Nickel Phosphide-Based Heterostructures for Electrochemical Hydrogen Evolution Reaction

“…5e. 96 Nanosheet morphology was confirmed by scanning electron microscopy (SEM), as shown in Fig. 5f.…”