Cobalt-Based Fischer–Tropsch Synthesis: A Kinetic Evaluation of Metal–Support Interactions Using an Inverse Model System

Abstract

Metal–support interactions in the cobalt–alumina system are evaluated using an inverse model system generated by impregnating Co3O4 with a solution of aluminum sec-butoxide in n-hexane. This results in the formation of nano-sized alumina islands on the surface of cobalt oxide. The activated model systems were kinetically evaluated for their activity and selectivity in the Fischer–Tropsch synthesis under industrially relevant conditions (220 °C, 20 bar). The kinetic measurements were complemented by H2-chemisorption, CO-TPR, and pyridine TPD. It is shown that the introduction of aluminum in the model system results in the formation of strong acid sites and enhanced CO dissociation, as evidenced in the CO-TPR. The incorporation of aluminum in the model systems led to a strong increase in the activity factor per surface atom of cobalt in the rate expression proposed by Botes et al. (2009). However, the addition of aluminum also resulted in a strong increase in the kinetic inhibition factor. This is accompanied by a strong decrease in the methane selectivity, and an increase in the desired C5+ selectivity. The observed activity and selectivity changes are attributed to the increase in the coverage of the surface with carbon with increasing aluminum content, due to the facilitation of CO dissociation in the presence of Lewis acid sites associated with the alumina islands on the catalytically active material.

Stable and Surface‐active Co Nanoparticles Formed from Cation (x) Promoted Au/x‐Co3O4 (x=Cs) as Selective Catalyst for [2+2+1] Cyclization Reactions

“…The effect of H 2 and CO gas in the catalyst‘s reducibility suggests that it improves the reduction behavior of Co 3 O 4 [26,36] . In this work, the gold nanoparticle‘s role was believed to cause a spillover effect of the H 2 and CO gas on the catalyst surface.…”

“…The effect of H and CO gas in the catalyst's reducibility suggests that it improves the reduction behavior of Co O 4 . [26,36] In this work, the gold nanoparticle's role was believed to cause a spillover effect of the H 2 and CO gas on the catalyst surface. The H 2 gas, been more reducing (Figure 1c), reduces the mesoporous Co 3 O 4 to Co; the formed active Co species transformed a variety as-synthesized oxygen-tethered 1, 6 enynes to bicyclic cyclopentenones with excellent yields.…”

The Influence of Preparation Method on the Physicochemical Characteristics and Catalytic Activity of Co/TiO2 Catalysts

“…Cobalt-supported catalysts are quite promising for many reactions of environmental and industrial interest such as volatile organic compounds oxidation [1], CO 2 hydrogenation [2], the Fischer-Tropsch process [3,4], and electrocatalysis [5].…”

Editorial: Cobalt and Iron Catalysis

“…[54][55][56] (3) Which specific reactor configurations and process conditions are superior for targeting specific product ranges? [57][58][59][60] (4) Which processes are involved in catalyst deactivation, which ones dominate, and how can they be managed? (5) What are the relationships between homogeneous and heterogeneous catalysts?…”

“…The importance of cobalt, as a less expensive metal relative to the precious metals, for light-driven water oxidation [68] and electrochemical processes for hydrogen production [69] further highlights the potential of harnessing these metals in a way that benefits society. Regarding current methods that utilize carbon, such as the FTS process, a series of studies included here examine the effect of reaction conditions and promoters [70], investigate the kinetics [53,59,60], and examine the reaction route through computational modeling [71], with the aim of tailoring new formulations in a scientifically-driven manner [55,56,72]. This offers the potential to more effectively utilize the routes that are already available.…”