Enhanced Oxygen Evolution Reaction Performance in Co–Fe Hydroxides through Boron Doping

Abstract

Among hydrogen production methods, water electrolysis stands out, but its efficiency is hampered by the substantial energy barrier of the oxygen evolution reaction (OER). To address this, incorporating electron‐deficient boron (B) into Co–Fe hydroxide (CoFeOxHy) promotes higher oxidation states of involved metals, greatly enhancing OER activity and charge transfer capabilities. Herein, the synthesis of a range of amorphous CoFeB nanoparticles with varying Fe to (Co+Fe) atomic ratios achieved through a simple chemical reduction method using CoFe‐Prussian blue analogs as precursors and employing Mössbauer spectroscopy to observe structural characteristics before and after transformation is reported. Among these nanoparticles, the CoFe0.25B variant, exhibiting favorable electrochemical properties, is chosen and subsequently subjected to hydrolysis to yield CoFe0.25BOH nanoparticles, serving as an active catalyst for OER. At a current density of 10 mA cm−2, the overpotentials for CoFe0.25OxHy and CoFe0.25BOH are 362 and 310 mV, respectively, with Tafel slopes decreasing from 393 to 93 mV dec−1. Furthermore, the i–t test reveals no significant loss of electrochemical performance within 24 h, substantiating the efficacy of enhancing the electrocatalytic performance of CoFeOxHy through the introduction of electron‐deficient elements. This research offers novel insights into the development of efficient and stable water electrolysis catalysts.