caa a22 4500 606174397 CHVBK 20210128100737.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s11244-015-0405-x doi (NATIONALLICENCE)springer-10.1007/s11244-015-0405-x CO Dissociation at Vacancy Sites on Hägg Iron Carbide: Direct Versus Hydrogen-Assisted Routes Investigated with DFT [Elektronische Daten] [Melissa Petersen, Werner van Rensburg] The mechanism of activation of CO remains under debate in Fe-catalysed Fischer-Tropsch synthesis, in which iron carbides form under reaction conditions. Direct and H-assisted paths for CO activation and dissociation are investigated at carbon vacancy and non-vacancy sites on the Fe5C2(010) surface of Hägg iron carbide using density functional theory. The calculated overall energy barrier for direct and for H-assisted dissociation of CO via formation of an HCO intermediate is the same, 1.42 and 1.41eV, respectively, but the lowest energy paths are facilitated by different vacancy sites. Furthermore, dissociation at a non-vacancy site is only marginally higher in energy by 0.1eV. Dissociation through formation of a hydroxymethylidyne (COH) intermediate is less competitive kinetically. Springer Science+Business Media New York, 2015 Iron carbide nationallicence Surface nationallicence CO activation nationallicence Fischer-Tropsch synthesis nationallicence DFT nationallicence Petersen Melissa Sasol Technology (Pty) Ltd., R&D Division, 1 Klasie Havenga Road, 1947, Sasolburg, South Africa aut van Rensburg Werner Sasol Technology (Pty) Ltd., R&D Division, 1 Klasie Havenga Road, 1947, Sasolburg, South Africa aut Topics in Catalysis Springer US; http://www.springer-ny.com 58/10-11(2015-08-01), 665-674 1022-5528 58:10-11<665 2015 58 11244 https://doi.org/10.1007/s11244-015-0405-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11244-015-0405-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petersen Melissa Sasol Technology (Pty) Ltd., R&D Division, 1 Klasie Havenga Road, 1947, Sasolburg, South Africa aut NATIONALLICENCE 700 1- van Rensburg Werner Sasol Technology (Pty) Ltd., R&D Division, 1 Klasie Havenga Road, 1947, Sasolburg, South Africa aut NATIONALLICENCE 773 0- Topics in Catalysis Springer US; http://www.springer-ny.com 58/10-11(2015-08-01), 665-674 1022-5528 58:10-11<665 2015 58 11244