How to make electrocatalysts more active for direct methanol oxidation - Avoid PtRu bimetallic alloys!

被引:328
作者
Long, JW
Stroud, RM
Swider-Lyons, KE
Rolison, DR
机构
[1] USN, Res Lab, Surface Chem Branch, Washington, DC 20375 USA
[2] USN, Res Lab, Surface Modificat Branch, Washington, DC 20375 USA
关键词
D O I
10.1021/jp001954e
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Contrary to the current understanding of Pt-Ru electrocatalyzed oxidation of methanol, the bimetallic alloy is not the most desired form of the catalyst. In the nanoscale Pt-Ru blacks used to electrooxidize methanol in direct methanol fuel cells, (PtRu0)-Ru-0 has orders of magnitude less activity for methanol oxidation than does a mixed-phase electrocatalyst containing Pt metal and hydrous ruthenium oxides (RuOxHy). Bulk, rather than near-surface, quantities of electron-proton conducting RuOxHy are required to achieve high activity for methanol oxidation. The active catalyst forms a nanoscopic, phase-separated hydrons oxide-on-metal structure that retains the Pt metal-RuOxHy boundaries required to oxidize methanol fully to carbon dioxide and water.
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页码:9772 / 9776
页数:5
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