Deactivation of CeO₂‐based catalysts in the HCl oxidation reaction proceeds via selective bulk chlorination of the active CeO₂ component to form CeCl₃×nH₂O. We study the reactivation of two bulk‐chlorinated CeO₂‐based Deacon catalysts by oxygen treatment at 430 °C, namely pure CeO₂ and 20 mol % of CeO₂ supported on preformed ZrO₂ particles (20CeO₂@ZrO₂), with a dedicated experiment. In the flow reactor setup we determine in‐situ the degree of chlorination of the catalyst by quantifying down‐stream with in‐situ UV‐Vis spectroscopy the total amount of chlorine in the catalyst that is exchanged by reoxidation at 430 °C. The activity of deactivated 20CeO₂@ZrO₂ can be fully restored by oxygen exposure at 430 °C, while that of pure CeO₂ declines steadily. Since the UV‐Vis analytics is fast and sensitive, we can follow the kinetics of reoxidation. To rationalize the observed kinetics, we develop a modified Johnson‐Mehl‐Avrami‐Kolmogorov (JMAK) model based on a nucleation‐and‐growth approach for the reoxidation of the catalyst starting from the chlorinated phase. The fast reoxidation kinetics of chlorinated 20CeO₂@ZrO₂ is traced to a fast nucleation rate.

中文翻译：

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HCl氧化反应中基于CeO2的催化剂的再活化：氯化程度的原位定量和动力学建模

在HCl氧化反应中，基于CeO ₂的催化剂的失活是通过活性CeO ₂组分的选择性本体氯化而形成的CeCl ₃ ×nH ₂ O进行的。我们研究了通过氧气处理将两种基于本体的氯化CeO ₂的Deacon催化剂进行的失活。通过专门的实验，在430°C下，即纯CeO ₂和20 mol％的CeO ₂负载在预先形成的ZrO ₂颗粒（20CeO ₂ @ZrO ₂）上。在流动反应器设置中，我们确定原位通过使用原位UV-Vis光谱对下游进行量化来确定催化剂的氯化程度，即在430°C时通过再氧化交换的催化剂中的氯总量。失活的20CeO ₂ @ZrO ₂的活性可以通过在430°C下暴露于氧气来完全恢复，而纯CeO ₂的活性则稳定下降。由于UV-Vis分析既快速又灵敏，我们可以跟踪再氧化的动力学。为了使观察到的动力学合理化，我们基于成核和生长方法开发了一种改良的Johnson-Mehl-Avrami-Kolmogorov（JMAK）模型，用于从氯化相开始的催化剂再氧化。氯化20CeO ₂ @ZrO ₂的快速再氧化动力学 可以追溯到快速成核速率。