title: Structural and elemental influence from various MOFs on the performance of Fe@C catalysts for Fischer-Tropsch synthesis.
abstract: The structure and elementary composition of various commercial Fe-based MOFs used as precursors for Fischer-Tropsch synthesis (FTS) catalysts have a large influence on the high-temperature FTS activity and selectivity of the resulting Fe on carbon composites. The selected Fe-MOF topologies (MIL-68, MIL-88A, MIL-100, MIL-101, MIL-127, and Fe-BTC) differ from each other in terms of porosity, surface area, Fe and heteroatom content, crystal density and thermal stability. They are re-engineered towards FTS catalysts by means of simple pyrolysis at 500 °C under a N2atmosphere and afterwards characterized in terms of porosity, crystallite phase, bulk and surface Fe content, Fe nanoparticle size and oxidation state. We discovered that the Fe loading (36-46 wt%) and nanoparticle size (3.6-6.8 nm) of the obtained catalysts are directly related to the elementary composition and porosity of the initial MOFs. Furthermore, the carbonization leads to similar surface areas for the C matrix (SBETbetween 570 and 670 m2g-1), whereas the pore width distribution is completely different for the various MOFs. The high catalytic performance (FTY in the range of 1.9-4.6 × 10-4molCOgFe-1s-1) of the resulting materials could be correlated to the Fe particle size and corresponding surface area, and only minor deactivation was found for the N-containing catalysts. Elemental analysis of the catalysts containing deliberately added promoters and inherent impurities from the commercial MOFs revealed the subtle interplay between Fe particle size and complex catalyst composition in order to obtain high activity and stability next to a low CH4selectivity.
authors.affiliation: Catalysis Engineering, ChemE, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands. f.kapteijn@tudelft.nl j.gascon@tudelft.nl.
authors.forename: Tim A
authors.initials: TA
authors.lastname: Wezendonk
authors.forename: Quirinus S E
authors.initials: QSE
authors.lastname: Warringa
authors.forename: Vera P
authors.initials: VP
authors.lastname: Santos
authors.forename: Adam
authors.initials: A
authors.lastname: Chojecki
authors.forename: Matthijs
authors.initials: M
authors.lastname: Ruitenbeek
authors.forename: Garry
authors.initials: G
authors.lastname: Meima
authors.forename: Michiel
authors.initials: M
authors.lastname: Makkee
authors.forename: Freek
authors.initials: F
authors.lastname: Kapteijn
authors.forename: Jorge
authors.initials: J
authors.lastname: Gascon