Indications for a Surface Temperature Excess in Heterogeneous Catalysis

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• 作者：Lianjie Zhu ; Gert Frens
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：September 21, 2006
• 年：2006
• 卷：110
• 期：37
• 页码：18307 - 18312
• 全文大小：97K
• 年卷期：v.110,no.37(September 21, 2006)
• ISSN：1520-5207

文摘

We explored the surface temperature excess T = T^r - T^m (real reaction temperature T^r, measured catalysttemperature T^m) on the basis of experimental data, a gradually curved Arrhenius plot for CO oxidation reactionsover Pd/-Al₂O₃ catalysts. Such a plot could be an indication of the surface temperature excess in the2-dimensional reaction surfaces of catalysts. The positive or negative surface temperature excess could bedeveloped to be a general explanation for a gradually curved Arrhenius plot of a gas-solid catalytic system.This is a new insight into solving the puzzle on such common phenomena in heterogeneous catalysis. Byusing the reciprocal of the real reaction temperature T^r in the hypothetical 2-D reaction surface, instead of theexperimentally determined catalyst temperature T^m or the gas temperature T^g, the gradually curved Arrheniusplot becomes linear. We investigated the implications of such a difference among T^r, T^m, and T^g. The surfacetemperature excess could be the effect of coupling between the fluxes of a chemical reaction and heat transportin the 2-D reaction surface. Its order of magnitude is 10 K for the present model system.¹ The surfacetemperature excess increases exponentially with the reaction temperature.