Monolithic SiC supports with tailored hierarchical porosity for molecularly selective membranes and supported liquid-phase catalysis

• Published in: Catalysis today Vol. 383; pp. 44 - 54
• Main Authors: Portela, Raquel, Marinkovic, Jakob Maximilian, Logemann, Morten, Schörner, Markus, Zahrtman, Nanette, Eray, Esra, Haumann, Marco, García-Suárez, Eduardo J., Wessling, Matthias, Ávila, Pedro, Riisager, Anders, Fehrmann, Rasmus
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2022
• Subjects: Catalysis; Hydroformylation; Molecularly selective membrane; Monolith; Porosity; Silicon carbide; Silicon carbide; Molecularly selective membrane; Porosity; Catalysis; Monolith; Hydroformylation
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.06.045

[Display omitted] •Wall-flow channeled monoliths with trimodal pore-size distribution.•SiC monoliths with core-skin hierarchical macroporosity allow membrane coating.•Homogeneous loading of SiO2 or Al2O3 nanoparticles into the SiC macropores.•Texture defined by SiC porosity, nanoparticle composition, size and load, and calcination temperature.•Efficient Rh-catalyst immobilization, hydroformylation integrated membrane reactor feasible. Monolithic support materials with the mechanical resistance and thermal conductivity of SiC as well as tunable surface chemistry and textural properties were developed for their use in catalytic membrane reactors. After heat treatment, the extruded SiC monoliths have a monomodal distribution of macropores of a few μm in diameter depending on the particle size of the starting material. A macroporous, defect-free, smoother skin was applied onto the external wall using a solution of sub-micrometer SiC particles. These monoliths with skin could be coated successfully with molecularly selective membranes, and thus have application in membrane reactor processes. Finally, metal oxide nanoparticles were infiltrated into the macropores to modify the surface texture and chemistry, allowing the immobilization of liquid phase catalysts. The resulting multimodal distribution of pore sizes could be tuned by the choice of SiC and oxide particle sizes, number of wash-coats and calcination temperature. Mesopores created between nanoparticles had diameters of roughly 40 % of those of the nanoparticles. Small macropores, between 10−1000 nm, were also created, with bigger size and volume at higher calcination temperatures due to the metal oxide particles contraction. The developed materials were validated as support for PDMS membranes and for continuous gas-phase hydroformylation of 1-butene using Rh-diphosphite catalysts.