Dealing with carbon dioxide waste is an on-going societal and technological challenge. One attractive proposition is to chemically convert waste carbon dioxide into useful chemical products. One possible route is to combine two well-known chemical processes, reverse water gas shift and Fischer-Tropsch synthesis, to make a catalyst capable of converting carbon dioxide directly intohydrocarbons. Iron nanoparticles supported on carbon nanotubes (CNT) have shown promise in the Fischer-Tropsch process. In this thesis, iron nanoparticles supported on carbon nanotubes (Fe@CNT) are shown to be effective catalysts for the coupled reverse water gas shift and Fischer-Tropsch reactions. Controlled oxidation of synthesised CNT can remove the graphitic shell from residual ironnanoparticles, activating them for catalysis. This process removes the need for expensive purification of CNT prior to use.Carbon nanotube powders generated in this way are difficult to handle, and could be difficult to scale-up. A method has been developed to grow long, aligned carbon nanotubes on a commercial cordierite monolith support, which has potential for scale up. The developed method does not require pre-treatment of the monolith prior to CNT synthesis. Using the same oxidation method these Fe@CNTs-monoliths have been demonstrated to act as catalysts for carbon dioxide conversion. The monolithic catalysts demonstrate improved mass transfer capabilities, leading to higher activities for the monolithic catalyst over a similar powder catalyst.
|Date of Award||13 Jun 2014|
|Supervisor||Davide Mattia (Supervisor), Matthew Jones (Supervisor), Andrew Johnson (Supervisor), Bob Tooze (Supervisor) & David Smith (Supervisor)|