Combining TAP-2 experiments with atomic beam deposition of Pd on quartz particles

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• 作者：Rebecca Fushimi ; John T. Gleaves ; Gregory Yablonsky ; Anne Gaffney ; Mike Clark ; Scott Han
• 关键词：TAP kinetic characterization ; Atomic beam deposition ; CO oxidation ; Oscillatory behavior ; Palladium catalysts
• 刊名：Catalysis Today
• 出版年：2007
• 出版时间：30 March 2007
• 年：2007
• 卷：121
• 期：3-4
• 页码：170-186
• 全文大小：2670 K

文摘

This paper presents a new approach for precisely tailoring the surface of complex catalytic particles at the atomic level. We describe a new apparatus of original construction that combines an atomic beam deposition (ABD) system with a temporal analysis of products (TAP-2) reactor system. Catalyst samples were prepared by directly adding metal atoms and metal oxide clusters in sub-monolayer amounts to the surface of micron-sized particles. Precise kinetic characterization, (non-steady-state and steady-state) was performed using pulse response methods, temperature-programmed reaction (TPR), etc.

The new approach is illustrated by the example of CO oxidation over a series of Pd/PdO catalysts. Catalysts of different loadings were prepared by direct atomic deposition on quartz particles. The Pd deposits were characterized using XPS, SEM and TEM. CO₂ production during TPR experiments exhibited oscillatory behavior. The goal of combining ABD with TAP experiments is to develop a method of establishing direct, reproducible correlations between changes in surface composition and changes in catalyst activity.