A series of CuZnSiAl catalysts with Si/Al molar ratios from 0 to 1 were prepared by a complete liquid-phase method and tested for syngas to higher alcohols (C2+OH) in slurry bed reactor. The catalysts were characterized by XRD, H-2-TPR, NH3-TPD, N-2 adsorption, FT-IR and XPS techniques. Activity results showed that the mass fractions of C2+OH in the total alcohols reached approximately 40.8% over CuZnAl catalyst without promoters. With increased Si/Al ratio, the crystallite size of Cu-0 first increased until Si/Al = 0.5 and then decreased, However, the total number of weak acid on catalysts surface increased continuously and the surface Cu content gradually decreased. In addition, compared with the acidic Si sol, the catalysts promoted by alkaline Si sol exhibited better performance in terms of both stability and selectivity to C2+OH. It was found that A1OOH functioned for CO dissociation and C2+OH synthesis simultaneously required relative larger Cu particles, more number of weak acid and higher Cu content on catalyst surface. The incorporation of a suitable amount of alkaline Si sol was beneficial for both the stability as well as C(2+)OHselectivity,and the best catalytic performance was obtained when the Si/Al atomic ratio was 0.5. (C) 2017 Hydrogen. Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.