Zeolite-templated Pt/C electrocatalysts

被引:21
作者
Coker, Eric N. [1 ]
Steen, William A. [1 ]
Miller, James E. [1 ]
机构
[1] Sandia Natl Labs, Albuquerque, NM 87185 USA
关键词
Pt cluster; electrocatalyst; activation energy; porous carbon; thermal treatment;
D O I
10.1016/j.micromeso.2007.02.044
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
In an effort to reduce the amount of platinum required in low temperature fuel cells, we have prepared electrocatalysts of platinum nanoparticles-on-carbon through zeolite-templating methods. Several different zeolite structure-types, as well as clays and mesoporous silicas were investigated as hosts for the preparation of small Pt clusters through thermal decomposition of ion exchanged (NH3)4Pt(2+). Several factors relating to cluster confinement and mobility influence cluster size, and clusters below 1 nm with narrow size distribution have been prepared. To enable electrochemical application, the pores of the Pt cluster-containing zeolite were filled with electrically conductive carbon via infiltration with carbon precursors, polymerization, and pyrolysis. The zeolite host was then removed by acid digestion, to leave a micro-/mesoporous Pt/C electrocatalyst possessing Pt clusters of controlled size. Preliminary electrochemical evaluation of these catalysts is reported. The energetics of thermal decomposition of (NH3)(4)Pt2+ to form Pt clusters in zeolite X have been investigated through Differential Scanning Calorimetry, and apparent activation energies calculated. The relationship between (NH3)4Pt2+ decomposition and conditions of calcination has been explored in an effort to better control Pt cluster sizes. (C) 2007 Elsevier Inc. All rights reserved.
引用
收藏
页码:236 / 247
页数:12
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