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Porosity and structure of hierarchically porous Ni/Al2O3 catalysts for CO2 methanation

DOI: 10.3390/catal10121471 DOI Help

Authors: Sebastian Weber (Karlsruhe Institute of Technology (KIT)) , Ken L. Abel (Universität Leipzig) , Ronny T. Zimmermann (Otto-von-Guericke University Magdeburg) , Xiaohui Huang (Karlsruhe Institute of Technology (KIT); Technische Universität Darmstadt) , Jens Bremer (Max Planck Institute Magdeburg) , Liisa K. Rihko-struckmann (Max Planck Institute Magdeburg) , Darren Batey (Diamond Light Source) , Silvia Cipiccia (Diamond Light Source) , Juliane Titus (Universität Leipzig) , David Poppitz (Universität Leipzig) , Christian Kübel (Karlsruhe Institute of Technology (KIT); Technische Universität Darmstadt) , Kai Sundmacher (Otto-von-Guericke University Magdeburg; Max Planck Institute Magdeburg) , Roger Gläser (Universität Leipzig) , Thomas L. Sheppard (Karlsruhe Institute of Technology (KIT))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Catalysts , VOL 10

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 24079

Open Access Open Access

Abstract: CO2 methanation is often performed on Ni/Al2O3 catalysts, which can suffer from mass transport limitations and, therefore, decreased efficiency. Here we show the application of a hierarchically porous Ni/Al2O3 catalyst for methanation of CO2. The material has a well-defined and connected meso- and macropore structure with a total porosity of 78%. The pore structure was thoroughly studied with conventional methods, i.e., N2 sorption, Hg porosimetry, and He pycnometry, and advanced imaging techniques, i.e., electron tomography and ptychographic X-ray computed tomography. Tomography can quantify the pore system in a manner that is not possible using conventional porosimetry. Macrokinetic simulations were performed based on the measures obtained by porosity analysis. These show the potential benefit of enhanced mass-transfer properties of the hierarchical pore system compared to a pure mesoporous catalyst at industrially relevant conditions. Besides the investigation of the pore system, the catalyst was studied by Rietveld refinement, diffuse reflectance ultraviolet-visible (DRUV/vis) spectroscopy, and H2-temperature programmed reduction (TPR), showing a high reduction temperature required for activation due to structural incorporation of Ni into the transition alumina. The reduced hierarchically porous Ni/Al2O3 catalyst is highly active in CO2 methanation, showing comparable conversion and selectivity for CH4 to an industrial reference catalyst.

Journal Keywords: methanation; carbon dioxide; hierarchical porosity; nickel; alumina; tomography; porosity analysis

Subject Areas: Chemistry, Materials, Physics


Instruments: I13-1-Coherence

Other Facilities: Karlsruhe Nano Micro Facility (KNMF)

Documents:
catalysts-10-01471.pdf