Co-Precipitated FeOx@MOy (M = Si, Al, Ce, Zr) Mesoporous Oxide Catalysts in the Reaction of CO2 Hydrogenation to C2+ Hydrocarbons: Effect of the Catalyst Composition and Synthesis

Two series of co-precipitated FeOx@MOy catalysts with variation of the second component (M = silica, alumina, ceria, zirconia) prepared using CTMABr or Pluronic 123 templates were investigated to assess the effect of the composition and synthesis in CO2 hydrogenation reaction to C2+ hydrocarbons. Alumina- or silica-modified samples were prepared by the CTMABr-assisted route, and alumina-, silica-, ceria-, or zirconia-modified samples were obtained using Pluronic 123. All samples demonstrated uniform component distribution over the surface (by SEM–EDX) with a ratio close to the target value, and the predominant phase in most samples was maghemite with crystallite sizes reaching 17 nm (by XRD). All samples had a mostly mesoporous structure with a small amount of micropores. The highest catalytic activity was achieved for samples containing alumina and zirconia additives in the range of 25 to 50%. The decrease in zirconia content from 25 to 1 wt% did not affect the CO2 conversion rate but led to a decrease in methane selectivity from 34 to 21%, while the C2+ selectivity remained constant 21%. The highest CO2 conversion rates at 340 °C and 20 atm (12.3 and 12.9 mol(CO2) × kgcat−1 × h−1) were achieved with Fe1/Al1 P123 and Fe3/Zr1 P123 samples. The highest C2+ selectivity (26%) at the same temperature and pressure was achieved for the monometallic Fe P123 sample, but its CO2 conversion rate was 5.4 mol(CO2) × kgcat−1 × h−1.