Momentary Equilibrium in Transient Kinetics and Its Application for Estimating the Concentration of Catalytic Sites

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• 作者：Evgeniy A. Redekop ; Gregory S. Yablonsky ; Vladimir V. Galvita ; Denis Constales ; Rebecca Fushimi ; John T. Gleaves ; Guy B. Marin
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：November 6, 2013
• 年：2013
• 卷：52
• 期：44
• 页码：15417-15427
• 全文大小：471K
• 年卷期：v.52,no.44(November 6, 2013)
• ISSN：1520-5045

文摘

We describe the novel concept of momentary equilibrium (ME), a special event during a pulse-response transient experiment in which the non-steady-state rates of adsorption and desorption of a probe molecule are instantaneously balanced. In the absence of other reactions, any system with reversible adsorption will always pass through ME during a pulse-response experiment with effusion. We also suggest a new method for measuring the concentration of adsorption sites on heterogeneous catalysts and the corresponding equilibrium constant by observing momentary equilibrium in thin-zone temporal analysis of products (TZTAP) pulse-response experiments with modulated pulse intensity. The suggested method employs reversible adsorption of probe molecules, contrary to traditional methods of counting adsorption sites which utilize irreversible reactions.