Influence of Chemical Composition on the Catalytic Activity of Small Bimetallic FeRu Nanoparticles for Fischer–Tropsch Syntheses
Résumé
FeRu nanoparticles were prepared according to an organometallic route using {Fe[N(Si(CH3)3)2]2}2 and (η4-1,5-cyclooctadiene)(η6-1,3,5-cyclooctatriene) ruthenium(0) Ru(COD)(COT) precursors followed by their insertion into a mesoporous MCF-17 support host. The resulting nanoparticles had a uniform size of approximately 2 nm, with a relative Ru amount of up to 33 at.%. Steady-state Fischer–Tropsch catalysis at 6 bar total pressure (H2/CO = 1:1) demonstrated light olefins production with a selectivity close to 50 % (ex. CO2) for catalysts with low Ru content (5 at.%). The selectivity pattern changed to long chain-paraffin production with increasing Ru amounts. These catalysts were also more active than those containing few Ru. X-ray photoelectron spectroscopy showed under-parity Ru amounts to effectively cover the surface of Fe nanoparticles. The nanoparticle distribution inside the MFC-17 host was characterized by microtomia/transmission electron microscopy.