Carbon layer-coated ordered mesoporous silica supported Co-based catalysts for higher alcohol synthesis: The role of carbon source

Surface chemical properties of supports have an important influence on active sites and their catalytic behavior. Here, we fabricated a series of cobalt-based catalysts supported by carbon layer-coated ordered mesoporous silica (OMS) composites for higher alcohol synthesis (HAS). The carbon layers were derived from different sources and uniformly coated on the porous surface of OMS. Combined with the characterization results of carbonized catalysts, it is demonstrated that the carbon layer-coated supports significantly enhanced the metal dispersion and increased the ratio of Co²⁺ to Co⁰ sites, which further increased the CO conversion and alcohols selectivity. Moreover, it is found that the catalytic activity changed in line with the amount of defects and surface oxygenic groups of carbon layers, which resulted from the different carbon sources. The highest space time yield of C₂₊OH was 27.5 mmol g_cat^-1 h^-1) obtained by the catalyst coated with glucose-derived carbon layer. But the carbon source is not the key factor influencing the distribution of Co-Co²⁺ dual sites and shows little effect on selectivity in HAS. These results may guide for further design of carbon supported catalysts.