Hydrogenation of CO 2 and CO by Fe catalysts obtained from Fe 2(CO) 9 and Fe 3(CO) 12 clusters supported on activated carbons

Abstract

Hydrogenation of carbon dioxide and carbon monoxide on iron catalysts prepared from Fe 2(CO) 9 and Fe 3(CO) 12 supported on four activated carbons were studied. The catalysts, prepared and reduced in H 2 at 673 K for 12 h, were characterized by H 2 and CO chemisorption and TEM. The catalysts prepared from Fe 3(CO) 12 had higher dispersion. The dispersion increased with increasing meso- and macropore volumes of the activated carbon. Hydrogenation of CO 2 produced CH 4 and CO, the rate of methane formation being much lower than that of CO formation; and both rates remained constant during reaction. However, in the hydrogenation of CO, the rate of methane formation and the CO conversion decreased with increasing reaction time, and hydrocarbons up to butane as well as CO 2 were detected among the reaction products. The differences found between the CO 2H 2 and the COH 2 reactions could be due to the different concentrations of CO surface species and to the possibility of the formation of metal oxides as a result of CO 2 dissociation.