Sintered Fe/CNT framework catalysts for CO2 hydrogenation into hydrocarbons

Because of its contribution to greenhouse effect, carbon dioxide conversion to valuable chemicals is one of the most challenging issues facing the modern world. A new type of iron catalysts of CO2 hydrogenation into hydrocarbons was synthesized by spark plasma sintering of carbon nanotubes decorated with iron oxide nanoparticles. This treatment produced carbon-encapsulated iron nanocrystals embedded in a dense framework of CNTs. The sintered catalysts were tested without pre-reduction in CO2 hydrogenation under supercritical conditions (350 °C, 8.5 MPa) and showed high specific activities of 5.4–12.2 molCO2gFe−1s−1 and promising C2+ selectivities of 40–50 mol.% at rather low H2:CO2 ratios of 1 and 2. The high efficiency of the catalysts was attributed to the stabilization of metal nanoparticles by carbon shells and increased density of CNT support, which led to higher degree of metal – support interaction and intensified carbidization and CO activation.