Electrocatalytic and structural investigation of trimetallic NiFeMo bifunctional electrocatalyst for industrial alkaline water electrolysis

Abstract

In pursuit of sustainable hydrogen production, alkaline water electrolysis offers fossil-free technology for generating hydrogen. Exploring new non-precious metal electrocatalysts plays a crucial role in this endeavor. Herein, we investigate a trimetallic NiFeMo material on a nickel foam support, serving as a bifunctional electrocatalyst for catalyzing both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Scanning electron microscopy reveals a nanosheet array structure with a uniform distribution of Ni, Fe, and Mo compounds on the electrode surface. Furthermore, the chemical surface composition of the pristine and spent electrodes is elucidated via x-ray photoelectron spectroscopy, displaying primarily oxidized species on the electrocatalyst surface. Bifunctional performance is assessed in a three-electrode setup, unveiling overpotentials of 70 mV for the HER and 140 mV for the OER, in a 30 wt% KOH electrolyte at 90°C. Additionally, in an industrial electrolysis cell, the activated electrode is evaluated as cathode and anode for 28 days, which decreased the overpotential of 330-350 mV at 200 mA cm−2 compared with pristine nickel foam. The performance increase of the electroplated coating is attributed to the increased surface area and enhanced intrinsic activity. The electrolysis cell experiences a ∼6% voltage loss during the experiment, indicating its robustness and suitability for industrial alkaline electrolysis applications.