Electrochemical deposited amorphous FeNi hydroxide electrode for oxygen evolution reaction

The electrodeposition approach is significant in electrode fabrication for practical application. Herein, the electrodeposited amorphous NiFe hydroxide species for oxygen evolution reaction (OER) in water splitting reaction is demonstrated by revealing the synergistic effect influenced by the support electrode of Fe and Ni foil and the contents of Fe and Ni in the electrolyte. All the electrodeposited samples have an amorphous structure and similar profiles of binding energy and chemical states for Fe and Ni as characterized by the spectroscopic techniques. While the support effect and Fe/Ni synergistic effect are indeed observed for the varied catalytic performances observed for the different electrodes; the Ni foil supported catalyst exhibits much higher performance than that of the Fe foil supported catalyst, and the different redox potentials of Ni species in the different Fe/Ni electrode resulting from the Fe–Ni synergism are observed in the cyclic voltammetry curve analysis. The surface roughness and the electrochemical surface area are also influenced by the support effect and the Fe/Ni ratio in the plating electrolyte. The optimal electrode shows a very low overpotential of ∼200 mV to reach 10 mA cm−2, and very high catalytic stability by the consecutive cyclic voltammetry measurements and 20 h stability test. Though it has the largest electrochemical surface area, the highest catalytic efficiency for these active sites is also indicated by the specific activity and turnover frequency polarization curves. The current work shows the effective experience for the electrodeposited Fe/Ni based catalysts in large-scale fabrication, which can be more practical for hydrogen generation in the alkaline water electrolysis.