The Enhancing Effect of α–FeOOH on Ni Surfaces Toward Electrolytic Water Splitting

For decades Ni has been known as an electrocatalyst for the oxygen evolution reaction (OER); however, the crucial role that Fe plays in enhancing the electrocatalytic activity of Ni still requires deeper investigation and understanding. Herein, some light on the role of Fe by studying the structural evolution of different Ni‐based electrocatalysts upon the electrolytic addition of different quantities of Fe are shaded. Colloidal Ni and NiO, as well as Ni, NiO, and NiNiO nanoparticles, are synthesized and electrochemically characterized in Fe‐free and Fe‐doped KOH electrolytes. Voltammetry and in situ Raman spectroscopy show that higher concentrations of Fe in the electrolyte lead to lower OER overpotentials due to the presence of α –FeOOH.