The inherent kinetic electrochemical reduction of oxygen into H sub(2)O on FeN sub(4)-carbon: A density functional theory study

• Published in: Journal of power sources Vol. 255; pp. 65 - 69
• Main Authors: Zhang, Jing, Wang, Zhijian, Zhu, Zhenping
• Format: Journal Article
• Language: English
• Published: 01.06.2014
• Subjects: Barriers; Carbon; Density functional theory; Displays; Hydrogenation; Mathematical analysis; Reaction kinetics; Reduction
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2014.01.008

Metal-coordinated nitrogen-doped carbons are highly active in promoting electrochemical oxygen reduction reaction (ORR). This study describes in detail the ORR kinetics on FeN sub(4)-graphene based on a density functional theory calculation. O sub(2) molecules chemisorbed on Fe site prefer hydrogenation into OOH species rather than direct breakage of the O-O bond. The subsequent reduction of OOH species into H sub(2)O sub(2) has a slightly high barrier (1.13 eV). However, this barrier could be bypassed by hydrogenation dissociation into O and H sub(2)O, which displays a low barrier (0.47 eV). Further O [arrowright] OH and OH [arrowright] H sub(2)O reactions are kinetically simple. Throughout the entire ORR, the initial O sub(2) [arrowright] OOH reaction determines the total rate and displays a reaction barrier of 0.62 eV. This kinetic profile suggests that O sub(2) molecules are inherently favorable for reduction into H sub(2)O on FeN sub(4)-graphene following a four-electron process.