Effect of the promoter and support on cobalt-based catalysts for higher alcohols synthesis through CO hydrogenation

Two series of supported Co-based catalysts were prepared using a facile co-impregnation method. The catalysts were examined in a fixed bed for their ability to selectively convert syngas into higher alcohols. Co–Cu and Co–CeO_2−xsites have an excellent synergistic effect, which could terminate the growth of the carbon chain effectively for the synthesis of alcohols. Furthermore, the Co–CeO_2−xsite is more beneficial for the synthesis of higher alcohols than the Cu–Co centre. The selectivity for the formation of ethanol and C₁–C₃alcohols achieved using the 10Co5Ce/carbon nanotubes catalyst were 29.7% and 89.5%, respectively. In addition, the separation of the Co and CeO_2−xsites weakens the synergistic effect, and thus, causes the formation of long chain hydrocarbons. The structure–performance correlation studies suggest that the geometric structure of the catalyst likely plays an important role in determining the formation of the Co–CeO_2−xsite, which influences the selectivity towards higher alcohols and higher aliphatic hydrocarbons.