Weber Sebastian, Batey Darren, Cipiccia Silvia, Stehle Matthias, Abel Ken L, Gläser Roger, Sheppard Thomas L
Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 20, 76131, Karlsruhe, Germany.
Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
Angew Chem Int Ed Engl. 2021 Sep 27;60(40):21772-21777. doi: 10.1002/anie.202106380. Epub 2021 Aug 31.
Understanding catalyst deactivation by coking is crucial for knowledge-based catalyst and process design in reactions with carbonaceous species. Post-mortem analysis of catalyst coking is often performed by bulk characterization methods. Here, hard X-ray ptychographic computed tomography (PXCT) was used to study Ni/Al O catalysts for CO methanation and CH dry reforming after artificial coking treatment. PXCT generated quantitative 3D maps of local electron density at ca. 80 nm resolution, allowing to visualize and evaluate the severity of coking in entire catalyst particles of ca. 40 μm diameter. Coking was primarily revealed in the nanoporous solid, which was not detectable in resolved macropores. Coke formation was independently confirmed by operando Raman spectroscopy. PXCT is highlighted as an emerging characterization tool for nanoscale identification, co-localization, and potentially quantification of deactivation phenomena in 3D space within entire catalyst particles.
了解积炭导致的催化剂失活对于含碳物种反应中基于知识的催化剂和工艺设计至关重要。催化剂积炭的事后分析通常通过体相表征方法进行。在此，使用硬X射线叠层成像计算机断层扫描（PXCT）研究了人工积炭处理后的用于CO甲烷化和CH干重整的Ni/Al O催化剂。PXCT以约80纳米的分辨率生成了局部电子密度的定量三维图，从而能够可视化和评估直径约40微米的整个催化剂颗粒中的积炭严重程度。积炭主要出现在纳米多孔固体中，在分辨出的大孔中无法检测到。通过原位拉曼光谱独立证实了焦炭的形成。PXCT作为一种新兴的表征工具，可用于在整个催化剂颗粒的三维空间中对失活现象进行纳米级识别、共定位以及潜在的定量分析。
