Characterization of TiO2-, ZrO2- and Al2O3-supported iron catalysts as used for CO2 hydrogenation Original Research Article

Alumina-, titania- and zirconia-supported iron oxides with an Fe loading of 5 wt.-% have been prepared by direct reduction of the precursors from incipient wetness impregnation and used for the synthesis of C2+-hydrocarbons from CO2 and H2. According to the conversion of CO2, the catalytic activity decreases in the following order: FeTiO2(B) ∼ FeZrO2(B)>FeTiO2(A)>FeZrO2(A)>FeAl2O3. XRD, Raman, Mössbauer and EXAFS analyses are employed for the characterization of the catalysts following the reduction treatment. The results suggest that conversion of CO2 to hydrocarbons is favored by the simultaneous presence of both zerovalent irons and coordinatively unsaturated cationic irons, among which ferric ions are for the Fe/ZrO2(B) and ferrous ions for the Fe/TiO2(B).