Boosting the Performance of Alkaline Anion Exchange Membrane Water Electrolyzer with Vanadium-Doped NiFe₂O₄

Developing efficient, economical, and stable catalysts for the oxygen evolution reaction is pivotal for producing large-scale green hydrogen in the future. Herein, a vanadium-doped nickel-iron oxide supported on nickel foam (V-NiFe₂O₄/NF) is introduced, and synthesized via a facile hydrothermal method as a highly efficient electrocatalyst for water electrolysis. X-ray photoelectron and absorption spectroscopies reveal a synergistic interaction between the vanadium dopant and nickel/iron in the host material, which tunes the electronic structure of NiFe₂O₄ to increase the number of electrochemically active sites. The V-NiFe₂O₄/NF electrode exhibited superior electrochemical performance, with a low overpotential of 186 mV at a current density of 10 mA cm^-2, a Tafel slope value of 54.45 mV dec^-1, and minimal charge transfer resistance. Employing the V-NiFe₂O₄/NF electrode as an anode in an alkaline anion exchange membrane water electrolyzer single-cell, a cell voltage of 1.711 V is required to achieve a high current density of 1.0 A cm^-2. Remarkably, the cell delivered an energy conversion efficiency of 73.30% with enduring stability, making it a promising candidate for industrial applications.