Iron‐Incorporated Cobalt Phosphate as an Efficient Electrocatalyst for Water Oxidation

Abstract

ABSTRACT The oxygen evolution reaction (OER) leads to intrinsically sluggish kinetics, requiring a high overpotential and significantly limiting the overall water splitting energy conversion efficiency. Co‐based catalysts have attracted considerable interest for the OER. Numerous studies have shown that trace Fe incorporation into Co‐based catalysts enhances electrical conductivity and increases active site density, thereby improving OER performance. However, Fe‐doped cobalt phosphates continue to encounter challenges, including intricate synthesis procedures, inadequate performance, and unclear mechanistic insights regarding the function of Fe. Herein, Fe‐incorporated Co 3 (PO 4 ) 2 ·8H 2 O (FCPO) was successfully synthesized via a simple hydrothermal method. Notably, compared with Co‐based phosphate electrocatalysts, the Fe incorporation modulates the electronic structure surrounding cobalt centers, facilitates cobalt valence transitions during OER. Besides, the exact location of Fe incorporation is determined through x‐ray absorption and clarified the role of Fe in cobalt phosphate catalyst for OER. The material displays outstanding OER performance in 1.0 M KOH, requiring a low overpotential of 233 mV to achieve 100 mA cm −2 .