A series of bifunctional catalysts composed of a component for higher alcohol synthesis （Cu-CoMn oxides, CCM） and an acidic zeolite （SAPO-34, ZSM-5, Y, MCM-41） were prepared for production of liquid hydrocarbon directly from a bio-syngas through a one-stage pro-cess. The effects of zeolite type, zeolite content, Si/Al ratio and preparation method on catalyst texture and its reaction performance were investigated. Higher selectivities and yields of liquid products were obtained by using bifunctional catalysts. The yields of liquid hydrocarbons decreased in the order CCM-ZSM-5〉CCM-SAPO-34〉CCM-Y〉CCM-MCM-41. CCM-ZSM-5 （20wt%, Si/Al=100） prepared by coprecipitation method displayed the optimal catalytic performance with the highest CO conversion （76%） and yield of liquid products （30%）. The catalysts were characterized by N2 adsorption/desorption, NH3-TPD, XRD, and H2-TPR analysis. The results showed that higher speci c surface areas and pore volumes of bifunctional catalysts were achieved by adding zeolites into CuCoMn precursors. Medium pore dimension and moderate acidity in CCM-ZSM-5 were observed, which proba-bly resulted in its excellent reaction performance. Additionally, a higher number of weaker acid sites （weak and/or medium acid sites） were formed by increasing ZSM-5 content in CCM-ZSM-5 or decreasing Si/Al ratio in ZSM-5. It was also seen that metal dispersion was higher and reducibility of metal ions was easier on the CCM-ZSM-5 catalyst prepared by coprecipitation. The higher alcohols-to-hydrocarbon process provides a promising route to hydrocarbon fuels via higher alcohols from syngas or biobased feedstocks.
A series of surfactant-modified CuCoMn-based catalysts were prepared for higher alco- hol synthesis from biomass-based syngas. Three typical surfactants, cetyltrimethylammonium bromide （CTAB）, sodium dodecyl sulfate （SDS） and pluronic P123 triblock copolymer （EO20PO70EO20）, were employed. Compared to surfactant-free CuCoMn catalyst, CO conversion increased from 17.4% to 29.7% over SDS-modified CuCoMn catalyst, and the selectivity of higher alcohols increased from 22.0% to 41.2% over CTAB-modified catalyst. Besides, the proportions of higher alcohols in total alcohols increased over all surfactantmodified catalysts. The catalysts were characterized by N2 adsorption/desorption, XRD, XPS and IR analysis. The results showed that several more favorable features rendered the CTAB-modified CuCoMn catalyst to be suitable for higher alcohol production, such as the larger pore size, better crystallinity of CuCoMnO4 spinel. moderate surface atomic distribution and lower valence of metallic ions. In addition, it was verified that CTAB addition at the metal precipitation stage was beneficial to higher alcohol synthesis. Surfactant-induced modification provides a promising alternative method for catalyst improvement in synthesis of higher alcohols.
