Sequential hydrothermal synthesized Co–Mn-oxide/C electrocatalysts for oxygen reduction in alkaline media. (13th August 2019)

• Record Type: Journal Article
• Authors: Si, Fengzhan; Kang, Xiaomin; Mattick, Victoria F.; Fu, Guodong; Fu, Xian-Zhu; Huang, Kevin
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 39(2019)
• Page Start: 21673
• Page End: 21682
• Publication Date: 2019-08-13
• Subjects: Oxygen reduction reaction -- Electrocatalyst -- Hydrothermal synthesis -- Co–Mn-oxide/C; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.06.104
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In order to design and synthesize oxygen reduction reaction catalysts with high activity and low cost, a series of Co–Mn-oxide/C catalysts with different Co:Mn ratios have been prepared using a hydrothermal method applied in sequential steps. The monotonically systematic trends of the catalysts' phases, morphologies and particle sizes have been verified, and the trending of Mn ions and Co ions in different valence states follows the increasing Co:Mn ratio. Electrochemical performance of the catalysts in oxygen reduction reaction results in a volcano-type trend with an optimal Co:Mn ratio of 3 giving the best performance, which is comparable to that of commercial Pt/C. Lastly, a Koutecky-Levich approach has been employed to deduce the electron transfer values, in an attempt to rationalize their selectivity towards the varying 2 and 4 electron pathways. The systematic research is significant for understanding and designing a new generation of non-noble metal oxygen reduction reaction catalysts. Highlights: Co–Mn-oxide/C catalysts with different Co:Mn ratios prepared by hydrothermal method. Monotone trends of phase, morphology, size and different valence ions, vs Co:Mn ratio. Volcanic type trend of electrochemical performance in ORR, vs Co:Mn ratio. Comparable performance to that of commercial Pt/C, e.g. on-set potentials. Way out for improving this series of catalysts as selectivity enhances.