Ultrafast Formation of Amorphous Bimetallic Hydroxide Films on 3D Conductive Sulfide Nanoarrays for Large‐Current‐Density Oxygen Evolution Electrocatalysis

Developing nonprecious oxygen evolution electrocatalysts that can work well at large current densities is of primary importance in a viable water‐splitting technology. Herein, a facile ultrafast (5 s) synthetic approach is reported that produces a novel, efficient, non‐noble metal oxygen‐evolution nano‐electrocatalyst that is composed of amorphous Ni–Fe bimetallic hydroxide film‐coated, nickel foam (NF)‐supported, Ni3S2 nanosheet arrays. The composite nanomaterial (denoted as Ni‐Fe‐OH@Ni3S2/NF) shows highly efficient electrocatalytic activity toward oxygen evolution reaction (OER) at large current densities, even in the order of 1000 mA cm−2. Ni‐Fe‐OH@Ni3S2/NF also gives an excellent catalytic stability toward OER both in 1 m KOH solution and in 30 wt% KOH solution. Further experimental results indicate that the effective integration of high catalytic reactivity, high structural stability, and high electronic conductivity into a single material system makes Ni‐Fe‐OH@Ni3S2/NF a remarkable catalytic ability for OER at large current densities. An ultrafast (5 s) synthetic approach that produces a novel, nonprecious oxygen‐evolution electrocatalyst comprising a 3D hierarchical core@shell Ni‐Fe‐OH@Ni3S2 nanostructure supported on nickel foam is presented. The material integrates the structural and catalytic advantages of amorphous Ni–Fe–OH and Ni3S2 nanosheet arrays, possessing an excellent ability to efficiently and stably electrocatalyze the oxygen evolution reaction at large current densities.