FeP/NiCoP Nanowire Arrays with an Optimized Coordination Environment for Electrocatalytic Water Splitting

Rational design and construction of a high-activity bifunctional nonprecious metal catalyst for overall water splitting is vital for hydrogen fuel production. In this work, a novel FeP/NiCoP nanowire array (FCNP nanowires) with porosity loaded onto carbon cloth is designed and prepared via a simple two-step route. The precise regulation of coordination number (CN) adjusts the electron configuration and micromorphology of the composite catalyst, which can optimize the adsorption/desorption of hydrogen/hydroxyl in an alkaline electrolyte, thus improving catalytic activity. As expected, the FCNP nanowire requires only 87.9 and 247.3 mV overpotentials at a current density of 10 mA cm–2 for a hydrogen evolution reaction (HER) and at a current density of 100 mA cm–2 for an oxygen evolution reaction (OER) in an alkaline electrolyte, respectively, outperforming most related catalysts reported. The corresponding low Tafel slopes of 54.4 mV dec–1 and 25.8 mV dec–1 and low charge transfer resistance (Rct) suggest its quick reaction kinetics. Moreover, the assembled electrolyzer applying the FCNP nanowire as both the cathode and anode only needs 1.63 V to deliver a current density of 20 mA cm–2. This work provides a new insight for constructing high-activity catalysts with a clear correlation between the coordination environment and intrinsic catalytic activity.