Chemical Synthesis and Preliminary Electrochemical Evaluation of a Ni–Fe–B Material for the Oxygen Evolution Reaction in Alkaline Medium

Abstract

The oxygen evolution reaction (OER) constitutes one of the main kinetic limitations in water electrolysis, motivating the development of electrocatalysts based on earth-abundant elements. In this work, the chemical synthesis of a material with a nominal Ni–Fe–B composition was carried out via aqueous phase reduction with sodium borohydride, followed by a preliminary electrochemical evaluation in 1 M KOH. The material was deposited by drop-casting onto a glassy carbon electrode and evaluated in a three-electrode cell. The reaction onset was evaluated through polarization curves obtained by linear sweep voltammetry (LSV) at 1 mV/s. Meanwhile, cyclic voltammetry in a non-faradaic window at different scan rates allowed estimating the double-layer capacitance (Cdl) and the electrochemically active surface area (ECSA), achieving an apparent roughness factor of 7.5.