The impact of tandem dehydrogenation-aldol condensation reactions on the structure of oxide-supported PdCu catalysts was studied by a combination of X-ray tomography measurements, ensemble-averaging spectroscopy techniques and reactivity measurements. X-ray tomography measurements generated 3D images at submicron resolution of the packed catalyst in the flow reactor following its exposure to various reaction conditions. Quantitative analysis of the tomography data revealed that exposure of the catalyst to reaction conditions induced structural deformation of the mixed Mg-Al oxide supports, accompanied by sintering of the PdCu nanoparticles into micron-sized aggregates. Improved stability was achieved once the PdCu particles were supported on an oxide, such as anatase TiO2, which does not undergo restructuring or phase transition under reaction conditions. This study demonstrates that structural information extracted by X-ray tomography measurements may uncover important structure-reactivity correlations and identify the reasons for catalysts deactivation.
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© 2018 Elsevier B.V.
- Pd-Cu nanoparticles
- X-ray tomography