Unraveling the Role of Fe into Co-based Electrocatalyst with Extremely Stable Cell Potential in Alkaline Water Electrolysis

Abstract

Corrosion resistive carbon coated Co-Fe alloy using electrospinning is proposed as a highly active and stable electrocatalyst for oxygen evolution reaction (OER). Tuned oxophilicity by modulating the electronic structure by Fe doping significantly promotes OER performance of Co. To establish optimal composition of Co and Fe, Co1-xFex-CNF were fabricated with various ratio of alloy. Among them, Co0.9Fe0.1-CNF exhibits the optimum oxygen evolution performance due to lowering the potential determining step (PDS) energy compared to that of Co-CNF with enhanced oxophilicity by Fe incorporation. In-situ XANES verified the existence of Co4+ which reflects the enlarged amount of M-OHads and M-Oads. The main reason of catalytic degradation might be understood owing to the oxidation of carbon. High degree of defects originated from microporous carbon was vulnerable in alkaline oxygen evolution environment. High metal loaded H–Co0.9Fe0.1-CNF with the highest degree of graphitization showed superior activity and stability in anion exchange membrane water electrolyzer.