Preparation Of Co-Ni Supported Catalyst For Upgrading Fermentation Products To Renewable Fuel Precursors

During the development and utilization of fossil energy for more than half a century,which caused a series of ecological and environmental problems,such as the greenhouse effect,acid rain,and dust.As well as facing the severe challenge of resource excessive consumption,which is forcing people to seek new energy that can replace fossil energy.Biomass energy,the new energy with carbon neutrality,reproducibility and easily available,which are derived from pyrolysis for lignocellulosicand and further upgrading.This article focuses on the highly selectivity condensation of ABE?acetone,n-butanol,and ethanol?that were obtained by the fermentation of sugars with low-values to synthesize high-quality chemicals or renewable fuel precursors.Firstly,a series of Co/Co₃O₄ magnetic transition metal catalysts were prepared by using hydrogen-liquid phase method to reduce Co₃O₄ under different reduced pressure,temperature and time.Acetone-butanol was used as reaction substrate to investigate catalytic performance.Studies have shown that Co⁰ has a good selectivity for aldol condensation,and its content and degree of dispersion on the catalyst surface are crucial.Among all catalysts,Co/Co₃O₄-1.5-200-3 catalyst provide the best catalytic performance at 200°C and 1.7MPa for 20h in N₂,giving a low conversion of 17.7%to acetone and a selectivity of 45.1%to long-chain alcohol ketones(C₇-C₁₁)in the condensation reaction of n-butanol with acetone.Meanwhile,activity gradually weaken with the further reducion of Co₃O₄.In order to improve the dispersion of Co⁰,we used AC with low cost,rich pore structure,large specific surface area and high chemical stability as carrier,and prepared a series of Co/AC catalysts at different reduction temperatures using wet impregnation,and acetone-butanol was also used as the reaction substrate to investigate catalytic performance.Giving a good conversion of 50.1%to acetone,and a total selectivity of 61.6%to 2-heptanone and 6-undecanone.Secondly,introducing another active component Ni with superior dehydrogenation performance and Mg-Al mixed metal oxide that containing basic sites.An investigation on the effect of the support,the metal loading,the ratio of Co/Ni,adding amount of activated carbon,preparation conditions,reaction temperature and reaction pressure was implemented.Under the same reaction conditions,Co-Ni/Mg-Al-C-750 catalyst showed the excellent catalytic performance with a conversion of 88.5%to acetone and a total selectivity of 94.4%to target products for the aldol condensation of acetone-butanol,as well as a conversion of 76.4%to acetone and a total selectivity of 89.9%to target products for the aldol condensation of acetone-butanol-ethanol.Results from XRD and BET analyses indicate that the adding of activated carbon improved the texture properties of the catalyst,enlarged the pore volume and average pore size,resulting in decrease of the mass transfer resistance in reaction.Results from XPS,H₂-TPR and TEM,revealing that the bimetallic synergy effect caused by the strong interaction between Co and Ni,and the formation of Co-Ni alloys greatly improved the selectivity of the target products.Results from CO₂-TPD and NH₃-TPD analyses proves that a certain amount of moderate intensity acidic sites,strong acidic sites and weak basic sites are essential for the condensation reaction.