1. AgSn intermetallics as highly selective and active oxygen reduction electrocatalysts in membraneless alkaline fuel cells.
- Author
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Wang, Qiao, Chen, Fuyi, Liu, Yaxing, Gebremariam, Tesfaye Tadesse, Wang, Junpeng, An, Liang, and Johnston, Roy L.
- Subjects
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INTERMETALLIC compounds , *OXYGEN reduction , *CHEMICAL reduction , *ELECTROCATALYSTS , *ALKALINE fuel cells - Abstract
Abstract The Ag 4 Sn and Ag 3 Sn intermetallics are successfully synthesized by combining electrochemical deposition and dealloying methods. The Ag 4 Sn and Ag 3 Sn possess a half-wave potential of 0.810 mV and 0.790 mV respectively for the oxygen reduction reaction in alkaline media, which are comparable to the commercial Pt/C (0.837 mV). In term of the durability, the Ag 4 Sn retains a half-wave potential of 0.775 mV after 5000 potential cycles, which is superior to Pt/C of 0.784 mV. The better catalytic activity and durability are mainly attributed to the ensemble effect and strong chemical bond in the AgSn ordered intermetallic structure. The catalytic activity is hardly influenced by methanol or ethanol in alkaline media with alcohol concentrations up to 1.0 M. Therefore, a membraneless alkaline zinc-air battery and direct alcohol fuel cell can operate with Ag 4 Sn and Ag 3 Sn intermetallics as the cathode catalysts, which allow the anode fuel to freely enter the cathode. A high power density is delivered by the membraneless alkaline fuel cells with zinc, methanol or ethanol as anode fuels. The excellent alcohol-tolerance is beneficial to the oxygen reduction reaction of alkaline fuel cells and makes the AgSn intermetallics a promising candidate to replace Pt-based electrocatalysts for oxygen reduction reaction. Highlights • AgSn intermetallics were successfully synthesized by an electrochemical method. • AgSn intermetallics exhibited excellent ORR activity and stability. • AgSn intermetallics showed superior tolerance to alcohol than commercial Pt/C. • High catalytic properties are attributed to ensemble effect and ordered structure. • Membraneless alkaline fuel cells based on selective catalysts were designed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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