Self-supported ternary (NixFey)2P nanoplates arrays as an efficient bifunctional electrocatalyst for overall water splitting

Abstract

Developing non-precious metal bifunctional electrocatalysts for effective overall water splitting is promising to realize high-efficient renewable energy production. In this work, ternary (NixFey)2P nanoplates arrays on 3D self-supported nickel foams were prepared through a simple coelectrodeposition followed by phosphorization. The synthesized (NixFey)2P nanoplates arrays showed remarkable bifunctional electrocatalytic performances in the KOH electrolyte, with the Tafel slopes of 57.8 mV·dec−1 and 53.6 mV·dec−1, and low overpotentials of 115 mV and 182 mV to reach a current density of 10 mA cm−2 for hydrogen evolution reaction and oxygen evolution reaction, respectively. In addition, the optimized (Ni0.66Fe0.33)2P anode and cathode demonstrated outstanding ability for overall water splitting in the two-electrode alkaline electrolyzer, generating a current density of 10 mA cm−2 at the applied cell voltage of 1.61 V. This benefited by the active surface to expedite reactants absorption, faster electron transport in the solid-liquid interface and reduced charge-transfer resistance due to the bimetallic synergistic effect. This delicate design of bifunctional transition metal phosphides provides a potential approach to realize water reuse and energy regeneration by the full water splitting.