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 (R_ct) 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.