Preparation of silicon foam supported CoMn catalysts and their catalytic performances in higher alcohol synthesis via syngas

A series of silicon foam supported CoMn catalysts were prepared using impregnation, precipitation, and hydrothermal methods. Combining the characterization techniques such as XRD, H₂-TPR, N₂ physical adsorption, TEM, and XPS, the effect of different catalyst preparation methods on the catalytic performance in the synthesis of higher alcohols from syngas was investigated. It is shown that there are Co²⁺(Co₂C) and Co⁰ species on the surface of the catalyst. The active sites of Co₂C-Co⁰ on the surface of the catalyst prepared by hydrothermal method have a good synergistic effect, which is conducive to the generation of alcohols. A higher proportion of Co₂C also promotes the associative adsorption and insertion of CO, resulting in the highest alcohol selectivity. Under the reaction conditions of t=260 °C, p=5.0 MPa, GHSV=4500 h^–1 and H₂/CO(volume ratio)=2:1, the catalyst exhibited the best reaction performances with CO conversion of 11.1%, total alcohol selectivity of 34.7%, and C₂₊OH selectivity of 34.5%.