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In Situ Preparation of Ca0.5Mn0.5O/C As a Novel High-activity Catalyst for the Oxygen Reduction Reaction

Authors Lyu, Yuqi HKUST affiliated (currently or previously)
Chen, Chi HKUST affiliated (currently or previously)
Gao, Yang HKUST affiliated (currently or previously)
Saccoccio, Mattia HKUST affiliated (currently or previously)
Ciucci, Francesco View this author's profile
Issue Date 2016
Source Journal of Materials Chemistry A , v. 4, (48), 2016, p. 19147-19153
Summary Rock-salt-type MnO is rarely used as an electrocatalyst because of its relatively poor activity. Herein, through an in situ preparation and Ca-substitution of MnO/C, we were able to obtain a novel composite, i.e., Ca0.5Mn0.5O/C, as a highly active, stable, and cost-effective oxygen reduction reaction (ORR) catalyst in alkaline media. Ca0.5Mn0.5O/C and MnO/C share a similar rock-salt phase. In comparison to MnO/C, Ca0.5Mn0.5O/C follows a more effective four-electron pathway (versus a two-electron pathway) and displays higher ORR activity, including a more positive onset potential (by 0.05 V), a more positive half-wave potential (by 0.04 V), and a higher current density (by 1.48 mA cm-2). The Ca0.5Mn0.5O/C also shows comparable mass activity, higher activity per material cost, and superior stability in alkaline media in comparison to commercial Pt/C. Additionally, the as-prepared Ca0.5Mn0.5O/C exhibits higher ORR activity than the physical mixture of Ca0.5Mn0.5O and carbon. The enhanced ORR performance of Ca0.5Mn0.5O/C is likely due to (1) the presence of the divalent redox pair MnII/MnIII; (2) the formation of MnOOH on the Ca0.5Mn0.5O surface; and (3) a stronger synergistic interaction between Ca0.5Mn0.5O and C resulting from the in situ preparation method. This work provides new routes to develop advanced electrocatalysts using transition-metal-oxide/carbon composites. © The Royal Society of Chemistry.
ISSN 2050-7488
Language English
Format Article
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