In situ observation of self-assembled hydrocarbon Fischer-Tropsch products on a cobalt catalyst
article
Fischer-Tropsch synthesis is a heterogeneous catalytic reaction that creates approximately 2% of the world's fuel. It involves the synthesis of linear hydrocarbon molecules from a gaseous mixture of carbon monoxide and hydrogen at high pressures (from a few to tens of bars) and high temperatures (200-350 €...°C). To gain further insight into the fundamental mechanisms of this industrial process, we have used a purpose-built scanning tunnelling microscope to monitor a cobalt model catalyst under reaction conditions. We show that, after 30 €...minutes of reaction, the terraces of the cobalt catalyst are covered by parallel arrays of stripes. We propose that the stripes are formed by the self-assembly of linear hydrocarbon product molecules. Surprisingly, the width of the stripes corresponds to molecules that are 14 or 15 carbon atoms long. We introduce a simple model that explains the accumulation of such long molecules by describing their monomer-by-monomer synthesis and explicitly accounting for their thermal desorption.
TNO Identifier
572684
ISSN
17554330
Source
Nature Chemistry, 8(10), pp. 929-934.
Publisher
MacMillan Nature Publishing Group
Collation
4 p.
Pages
929-934
Files
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