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

- Co-CeO2−x site terminates carbon chain growth effectively for alcohols synthesis.
- Separation of Co and Co-CeO2−x sites may cause the long chain hydrocarbon formation.
- Geometric structure plays an important role in determining product distribution.

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-CeO2−x sites have an excellent synergistic effect, which could terminate the growth of the carbon chain effectively for the synthesis of alcohols. Furthermore, the Co-CeO2−x site is more beneficial for the synthesis of higher alcohols than the Cu-Co centre. The selectivity for the formation of ethanol and C1-C3 alcohols achieved using the 10Co5Ce/carbon nanotubes catalyst were 29.7% and 89.5%, respectively. In addition, the separation of the Co and CeO2−x sites 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-CeO2−x site, which influences the selectivity towards higher alcohols and higher aliphatic hydrocarbons.

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