Needle in a haystack catalysis

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• 作者：Xiaolin Zheng ; John T. Gleaves ; Gregory S. Yablonsky ; Thomas Brownscombe ; Anne Gaffney ; Mike Clark ; Scott Han
• 关键词：Heterogeneous catalysis ; Single particle catalysis ; CO oxidation ; Temporal Analysis of Products (TAP) ; Platinum
• 刊名：Applied Catalysis A: General
• 出版年：2008
• 出版时间：15 June 2008
• 年：2008
• 卷：341
• 期：1-2
• 页码：86-92
• 全文大小：939 K

文摘

A new configuration of catalyst loading in the Temporal Analysis of Products (TAP) reactor is presented. It is a single Pt particle packed in a bed with approximately 100,000 inert quartz particles. In TAP studies, the single particle configuration was proven to be sensitive enough to monitor and compare kinetic characteristics of the same catalyst particle at both high vacuum and atmospheric pressures. Catalytic CO oxidation reaction over platinum was used to illustrate these new possibilities. In the TAP single particle experiments under high vacuum conditions, a single particle provides high conversion (up to a total conversion of 95 % ) despite the catalyst particle occupies less than 0.1 % of the total reactor volume. This phenomenon was proven in a variety of pulse response experiments. A mathematical probabilistic theory of this counterintuitive phenomenon will be published in the next paper. Also, an interesting similarity was found from both TAP vacuum and atmospheric pressure data, i.e. both sets of data are characterized by a “turning point” at the same temperature of 170 °C indicating a transition from an O₂ dominated regime to a CO dominated regime. This observation of pressure independent characteristic of the Pt particle creates a new possibility for bridging across the pressure gap.