Moderate oxophilic CoFe in carbon nanofiber for the oxygen evolution reaction in anion exchange membrane water electrolysis. (1st September 2020)

• Record Type: Journal Article
• Authors: Kang, Sinwoo; Ham, Kahyun; Lee, Jaeyoung
• Is Part Of: Electrochimica acta. Volume 353(2020)
• Publication Date: 2020-09-01
• Subjects: Oxygen evolution reaction -- Anion exchange membrane water electrolysis -- Non-noble metal catalyst -- Graphitic carbon -- In-situ XAFS; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.136521
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: We propose corrosion-resistant carbon-coated Co0.9 Fe0.1 alloy nanoparticles as highly active and durable electrocatalysts for the oxygen evolution reaction (OER) in anion exchange membrane water electrolysis (AEMWE). In the presence of 10% Fe atoms, the oxophilicity of Co metal is modulated in a direction to facilitate OH − adsorption on Co 3+ ; thus, Co0.9 Fe0.1 -carbon nanofiber (CNF) can exhibit smaller overpotentials than other metal ratios in Co1-x Fex -CNF. Additionally, we confirm catalytic degradation from the oxidation of the carbon layer, which is triggered by defects in the carbon originating from Fe during the pyrolysis step. The Co0.9 Fe0.1 metal is further optimized by increasing graphitization to simultaneously achieve superior activity and durability for application on AEMWE. This work not only demonstrates the role of Fe in Co metal for controlling the proper oxophilicity but also shows the importance of graphitized carbon as a catalyst support for stable water oxidation. Graphical abstract: Image 1 Highlights: Fe atom in CoFe alloy modifies the oxophilicity of Co by fostering OH − adsorption. Tuned oxophilicity in CoFe alloy makes plenty of Co 4+ ; activity toward OER improved considerably. Defects in carbon nanofiber cause carbon oxidation and catalyst degradation during oxygen evolution reaction. Graphitized H-Co0.9 Fe0.1 -CNF exhibits superior activity (794 mA cm −2 @ 1.7 V) in AEMWE.