Monolithic Al2O3 Xerogels with Hierarchical Meso‐/Macropore System as Catalyst Supports for Methanation of CO2. Issue 15 (22nd June 2022)

• Record Type: Journal Article
• Authors: Abel, Ken Luca; Beger, Tobias; Poppitz, David; Zimmermann, Ronny T.; Kuschel, Oliver; Sundmacher, Kai; Gläser, Roger
• Is Part Of: ChemCatChem. Volume 14:Issue 15(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-22
• Subjects: Aluminum Oxide -- CO2 Methanation -- Drying -- Monoliths -- Sol-Gel Synthesis -- Solvent Exchange; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202200288
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Cylindrical, cm‐sized monolithic Al2 O3 xerogels with hierarchical meso‐/macropore system were prepared by sol‐gel synthesis. The influence of both solvent exchange and drying on monolith stability and the resulting pore system was studied following mass and volume of the monolith as well as by porosimetry and electron microscopy. Crack‐free drying of the monoliths requires a proper management of drying stress. This is achieved by adjusting the drying rate and solvent exchange procedure applied to the intermediate lyogels. Moreover, mainly through differences in capillary pressure, changing the pore fluid allows an adjustment of the mesopore width from 7.6 nm to 10.5 nm. Neither solvent exchange nor drying affect the macropores, the width of which stays at 1.5 μm. Finally, CO2 methanation over Ni‐impregnated Al2 O3 monoliths reveals CO2 conversion and CH4 selectivity comparable to an industrial Ni/Al2 O3 benchmark catalyst. Abstract : Pore structure : Post‐gelation events, i. e . aging processes, solvent exchange and drying are vital for the preparation of Al2 O3 xerogel monoliths. However, they also have an effect of the resulting pore structure. This is exploited to change the mesopores of Al2 O3 monoliths from 7.6 nm to 10.5 nm without changing the macropores. Moreover, the Al2 O3 xerogels are successfully employed as catalyst support.