The synergistic role of metal and acid-base sites of Ni-MgSiO catalysts in the Guerbet reaction to convert n-butanol to 2-ethyl-1-hexanol

Upgrading biobutanol into transport fuels via the Guerbet reaction relies on multifunctional catalysts with well-balanced active sites. In this work, a Ni-MgSiO catalyst efficiently converted n-butanol to 2-ethyl-1-hexanol via the Guerbet reaction, achieving 52.1 % selectivity at 47.1 % conversion. The catalyst exhibited good recyclability with only a slight decrease in target product yield after three times recycling. Isotope experiments verified the Guerbet pathway and identified dehydrogenation as the rate-determining step. The characterizations revealed that oxygen vacancies and NiO-MgO solid solution synergistically enhanced dispersion and accessibility of Ni0 metal sites, while also modulating the acid-base properties. The well-dispersed Ni0 metal sites and base sites cooperatively catalyzed the dehydrogenation reaction, while balanced acid-base sites facilitated aldol condensation. Additionally, acid sites assisted Ni0 metal sites in the hydrogenation reaction. The precise match between active sites and each reaction step contributed to the catalyst's high performance. This work offers a viable strategy for developing high-performance Guerbet reaction catalysts to produce renewable fuels.