Confined Iron Nanoparticles on Mesoporous Ordered Silica for Fischer–Tropsch Synthesis

TONCÓN-LEAL, C. F.; AMAYA-RONCANCIO, S.; GARCÍA BLANCO, A. A.; MORENO, M. S.; SAPAG, K.

TOPICS IN CATALYSIS

SPRINGER/PLENUM PUBLISHERS

Año: 2019 vol. 62 p. 1086 - 1095

1022-5528

Iron oxide particles were deposited in an ordered mesoporous material (SBA-15) with the aim of studying its behavior inthe catalytic hydrogenation of CO (Fischer?Tropsch Synthesis). Bulk iron oxide, and iron supported on porous silica withdifferent textural properties (Aerosil®-200) were used for comparison. The characterization of the materials showed thatin the Fe@SBA-15 material, iron nanoparticles were confined inside the mesopores of the SBA-15 support (pore diameter~ 8 nm), and Fe@Aerosil®-200 material also presented iron oxide nanoparticles highly dispersed on the material. In situSynchrotron radiation XRD studies were performed in order to study the evolution of iron phases in the Fe@SBA-15 andthe bulk iron oxide under hydrogen and hydrogen/carbon monoxide conditions. DFT calculations were performed on bareFe(100) and a Fe16cluster in CO activation and CxHyhydrogenation. Catalytic microactivity tests, performed at conversionsof ~ 6?8%, showed important differences in the selectivity of the materials. Higher selectivity to methane and light hydrocarbonswere observed in the supported catalysts (Fe@SBA-15 and Fe@Aerosil®-200) than in bulk Fe catalyst. Moreover, thesupported catalysts showed selectivity to ethylene (Fe@SBA-15) and propylene (Fe@Aerosil®-200), products that were notobserved in the bulk iron catalyst. On the other hand, bulk iron showed a major selectivity to higher hydrocarbons (C5?C9)and oxygenates.