Preparation of a multilayered composite catalyst for Fischer–Tropsch synthesis in a micro-chamber reactor

Abstract

A 20 wt% Co/SiO2 catalyst grafted on a stainless steel substrate was used for Fischer–Tropsch synthesis (FTS) in a micro-chamber reactor. The fabrication of the catalyst was a complex process involving several steps. The first one, the pre-treatment of the AISI316L substrate through a plasma assisted chemical vapour deposition process (PACVD), allowed the formation of a silicon based polymer. This thin polymeric film was thermally degraded into a silicon oxide bonding layer. The coating of this bonding layer with sol–gel precursor of the Co/SiO2 catalysts was done with a spray coating process. The sequential combination of these steps led to a multilayered catalyst with a complex morphology. This material demonstrated high activity under FTS reaction. Activity and selectivity were higher under micro-chamber conditions than in a classical fixed-bed catalytic test. This was attributed to the increase of mass and heat transfers within the micro-device. Moreover distribution of metallic masses within the catalyst showed significant evolutions post FTS, including steel compound migrations and possible cobalt segregation.