Selectivity loss in Fischer-Tropsch synthesis: The effect of carbon deposition

On the link between CO surface coverage and selectivity to CH4 during CO2 hydrogenation over supported cobalt catalysts

“…The need to curb CO 2 emissions and the prospects of a future greater availability of dihydrogen produced from nuclear and renewable energies have raised interest in carbon capture and utilisation (CCU) 1 . The hydrogenation of CO 2 to methanol 2 , methane (Sabatier reaction) 3 and higher hydrocarbons (Fischer-Tropsch synthesis, FTS) 4,5,6 are all receiving renewed interests.…”

Impact of cobalt catalyst carburization on Fischer‐Tropsch micro‐kinetics

“…Several causes have already been identified to explain the deactivation phenomenon: carbon deposition 6–9 sulfur poisoning 10,11 carburization 12–14 water effects 15–19 and surface reconstruction 17,20 . The causes of the selectivity shift are however less documented, yet carburization and carbon deposition have recently been identified as a possible cause of deselectivation 21,22 …”

“…To this aim, the cobalt catalyst was carburized in situ and the subsequent activity and selectivity loss were monitored as a function of time using a high‐throughput testing facility 22 . This phenomenon has indeed been identified as a possible deselectivation mechanism, 22 before carbon deposition 21 or other deactivation mechanisms. The method presented in this study should, however, also be extended to the carbon deposition to propose a comprehensive deselectivation kinetic model.…”

“…17,20 The causes of the selectivity shift are however less documented, yet carburization and carbon deposition have recently been identified as a possible cause of deselectivation. 21,22 Numerous studies have been recently devoted to Fischer-Tropsch kinetics, and accurate models are now available in the literature. [23][24][25][26][27][28][29] Some of them take the deactivation phenomena into account in the proposed model, which is necessary to predict long-term performances.…”