A “Two‐Pronged” Strategy to Boost Hydrogen Evolution Kinetics on NiFe‐Based (Oxy)hydroxides via Oxygen Deficient Ni‐Mo‐Fe Coordinate Structures for Ultra‐Stable Ampere‐Level Alkaline Overall Water Splitting

Abstract NiFe (oxy)hydroxides have been regarded as one of the state‐of‐the‐art catalysts for oxygen evolution reaction (OER). Unfortunately, the sluggish hydrogen evolution reaction (HER) kinetics limit its application as bifunctional electrocatalyst for alkaline overall water splitting (OWS). Herein, a “two‐pronged” strategy is proposed to construct highly active oxygen deficient Ni‐Mo‐Fe coordinate structures in NiFe (oxy)hydroxide (NFM‐OV R /NF), which simultaneously reduces the energy barrier of Volmer and Heyrovsky steps during alkaline HER process and significantly accelerate the reaction kinetics. Consequently, NFM‐OV R /NF delivers overpotentials as low as 25 and 234 mV to achieve 10 and 1000 mA cm −2 in 1.0 M KOH, respectively. Furthermore, benefiting from excellent HER and OER activity, NFM‐OV R /NF exhibits a remarkable OWS activity with cell voltages of 1.44 V and 1.77 V at 10 and 1000 mA cm −2 in 1.0 M KOH, and displays ultralong‐term stability for 600 h at 500 mA cm −2 , while remaining durable for 300 h in an alkaline water electrolyzer in 30% KOH at 80 °C. The calculated price per gallon of gasoline equivalent for the produced H 2 is $ 0.92, which is much lower than 2026 U.S. Department of Energy target ($ 2.00), demonstrating feasibility and practicability of NFM‐OV R /NF for industrial applications.