Pt/CeZrO catalysts have shown high activity in water gas shift (WGS) reaction, but their structural organization has been studied insufficiently. This work represents a detailed structural study on the supported Pt species and the metal/support interface in a 5 wt% Pt/CeZrO catalyst in the initial state, after reductive activation, and after WGS reaction in H-enriched reformate-simulating mixture. A wide range of methods was used: and X-ray diffraction (XRD) studies, high resolution transmission electron microscopy (HRTEM), X-ray atomic pair distribution function (PDF) method, X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H-TPR). The CeZrO mixed oxide was shown to provide a highly dispersed state of Pt species. XPS revealed that the initial catalyst contains Ptspecies. PDF analysis allowed us to propose the structure of ultrafine PtO particles and to elucidate the metal-support interaction with fixation of Pt ions on the support surface. XRD, XPS, and H-TPR studies revealed the reduction of ultrafine PtO particles in H atmosphere at low temperatures (20–90°С) with the formation of metallic Pt particles and simultaneous partial reduction of the support surface due to the hydrogen spillover. Catalytic tests of the as-prepared and poisoned with chlorine 5wt% Pt/CeZrO catalysts in the WGS reaction showed an important role of the oxygen vacancies in the oxide support as active sites. These findings contribute to the understanding catalytic performance of Pt/CeZrO systems.

中文翻译：

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水煤气变换反应Pt/Ce0.75Zr0.25O2催化剂的非原位和原位结构特征研究

Pt/CeZrO催化剂在水煤气变换（WGS）反应中表现出高活性，但其结构组织研究还不够。这项工作代表了对 5 wt% Pt/CeZrO 催化剂在初始状态、还原活化后以及在富 H 重整油模拟混合物中进行 WGS 反应后的负载型 Pt 物质和金属/载体界面的详细结构研究。使用了多种方法：X射线衍射（XRD）研究、高分辨率透射电子显微镜（HRTEM）、X射线原子对分布函数（PDF）方法、X射线光电子能谱（XPS）、氢温度-程序化还原（H-TPR）。 CeZrO 混合氧化物被证明可以提供高度分散的 Pt 物质状态。 XPS 显示初始催化剂含有 Ptspecies。 PDF 分析使我们能够提出超细 PtO 颗粒的结构，并阐明金属与载体之间的相互作用以及 Pt 离子在载体表面的固定。 XRD、XPS 和 H-TPR 研究表明，超细 PtO 颗粒在低温 (20–90°С) 的 H 气氛中被还原，形成金属 Pt 颗粒，同时由于氢气溢出而导致载体表面部分还原。在 WGS 反应中对所制备的并用氯中毒的 5wt% Pt/CeZrO 催化剂进行的催化测试表明，氧化物载体中的氧空位作为活性位点的重要作用。这些发现有助于理解 Pt/CeZrO 系统的催化性能。