Abstract

The kinetics of the low-temperature forward water gas shift (LT-WGS) reaction have been studied over a 2 wt% Au/CeZrO₄ (Au/CZO) catalyst using both thermal and dielectric barrier discharge plasma heterogeneous catalyst systems. Using the energy density (ε), the apparent activation energy has been calculated under plasma and thermally activated conditions. A substantially lower apparent activation energy is observed in the plasma activated system (9.5 kJ/mol) compared with the thermal-catalysed reaction (132.9 kJ/mol). Different kinetic isotope effect (KIE) values for water were found in thermal (1.43) and plasma (1.89) activated catalytic systems which infer different mechanisms between the two activation processes and also shows the importance of water activation. Furthermore, negative and positive reaction orders with respect to CO and H₂O are found for both conditions which are − 1.30, 0.28 under thermal and − 1.53, 0.35 under plasma processes, respectively. The reaction order with respect to H₂O and KIE studies demonstrate that the bond cleavage in H₂O molecule is a rate determining step in the plasma-assisted LT-WGS, similar to that in the thermal-assisted reaction.

Graphic Abstract

中文翻译：

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Au / CeZrO 4上水煤气变换反应的动力学：常规加热和电介质阻挡放电（DBD）等离子体活化的比较

摘要

在2 wt％Au / CeZrO _4上研究了低温正向水煤气变换（LT-WGS）反应的动力学（Au / CZO）催化剂同时使用热障和电介质阻挡放电等离子体非均相催化剂体系。使用能量密度（ε），已经在等离子体和热活化条件下计算了表观活化能。与热催化反应（132.9 kJ / mol）相比，在等离子体活化系统中观察到的表观活化能低得多（9.5 kJ / mol）。在热（1.43）和等离子体（1.89）活化的催化体系中发现了不同的水动力学同位素效应（KIE）值，这推断出两种活化过程之间的机理不同，也表明了水活化的重要性。此外，关于CO和H _2的负反应顺序和正反应顺序两种条件下的O分别为热条件下的-1.30、0.28和等离子工艺下的-1.53​​、0.35。关于H ₂ O和KIE研究的反应顺序表明，在H ₂ O分子中的键断裂是等离子体辅助LT-WGS中的速率确定步骤，与热辅助反应中的类似。

图形摘要