Growth of carbon nanofibers synthesized from CO2 hydrogenation on a K/Ni/Al2O3 catalyst

Abstract We used a commercially available Ni/Al 2 O 3 sample containing K additive to enable carbon deposition from CO 2 exposure by means of catalytic hydrogenation. Our experimental results suggest that K additives induce the formation of carbon nanofibers (CNFs) or carbon deposition on Ni/Al 2 O 3 during the CO 2 hydrogenation reaction. We propose that the rate of carbon deposition depends on the reaction temperature, on H 2 and CO 2 partial pressures, and on the reactant residence time. Furthermore, we suggest that the creation of a K-relevant active phase may be involved in the carbon deposition process. Our results also indicate that the degree of CNF graphitization can change with reaction time.