Influence of sugars in preparing improved FeAl catalyst for carbon dioxide hydrogenation

The influences of sugars (sucrose, fructose and glucose) on the performance of FeAl catalysts were investigated for CO 2 hydrogenation. FeAl catalysts were prepared with two steps. At first, the catalyst precursors were obtained by co-precipitation. During this step, three methods were used to add sucrose into the precursors. Then, promoter K and Cu were impregnated into the precursors. The improved CO 2 conversion and C 5+ hydrocarbon selectivity by sucrose addition were attributed to the formation of γ-Fe 2 O 3 phase in the catalyst precursor, which was different from the popular opinion that sucrose acted as a chelating agent. With the inspiration from sucrose hydrolysis effect, FeAl oxide, mainly in γ-Fe 2 O 3 phase was prepared by adding fructose and glucose (the products of sucrose hydrolysis) into the newly centrifuged precipitate. The formation of γ-Fe 2 O 3 phase was explained based on the results of XRD and XPS. The best catalyst possessed CO 2 conversion of 30.3% and C 5 + selectivity of 52.2% under the reaction conditions of H 2 :CO 2 = 3:1, 6.0 L/(h·g-cat), 1.6 MPa and 235 °C. Graphic abstract Effects of fructose and glucose on FeAl catalyst