Muravev Valery, Simons Jérôme F M, Parastaev Alexander, Verheijen Marcel A, Struijs Job J C, Kosinov Nikolay, Hensen Emiel J M
Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
Angew Chem Int Ed Engl. 2022 Jun 7;61(23):e202200434. doi: 10.1002/anie.202200434. Epub 2022 Apr 5.
Aiming at knowledge-driven design of novel metal-ceria catalysts for automotive exhaust abatement, current efforts mostly pertain to the synthesis and understanding of well-defined systems. In contrast, technical catalysts are often heterogeneous in their metal speciation. Here, we unveiled rich structural dynamics of a conventional impregnated Pd/CeO catalyst during CO oxidation. In situ X-ray photoelectron spectroscopy and operando X-ray absorption spectroscopy revealed the presence of metallic and oxidic Pd states during the reaction. Using transient operando infrared spectroscopy, we probed the nature and reactivity of the surface intermediates involved in CO oxidation. We found that while low-temperature activity is associated with sub-oxidized and interfacial Pd sites, the reaction at elevated temperatures involves metallic Pd. These results highlight the utility of the multi-technique operando approach for establishing structure-activity relationships of technical catalysts.
针对用于汽车尾气净化的新型金属-氧化铈催化剂的知识驱动设计，目前的工作主要集中在合成和理解明确的体系上。相比之下，工业催化剂的金属形态往往是不均匀的。在此，我们揭示了传统浸渍法制备的Pd/CeO催化剂在CO氧化过程中丰富的结构动力学。原位X射线光电子能谱和操作X射线吸收光谱揭示了反应过程中金属态和氧化态Pd的存在。利用瞬态操作红外光谱，我们探究了CO氧化过程中表面中间体的性质和反应活性。我们发现，虽然低温活性与亚氧化态和界面Pd位点有关，但高温下的反应涉及金属态Pd。这些结果突出了多技术操作方法在建立工业催化剂结构-活性关系方面的实用性。
