Al2O3-cogelled Ru nanoparticle (Ru@Al) catalyst was prepared by a one-pot in-situ alumina gelation method using a PVP-stabilized Ru colloid solution. The Ru@Al catalyst exhibited excellent catalytic activity during the liquid-phase hydrodeoxygenation of vanillin, demonstrating 100% conversion, as well as significantly higher yields of fully deoxygenated compounds compared to other conventional alumina supported Ru catalysts. We also observed better selectivity to deoxygenated dimers with the Ru@Al catalyst. The improved catalytic selectivity was attributed to the hypothesized three-dimensional structures of Al2O3 surrounding the Ru nanoparticles, which improved the two-step reaction, containing the dimerization of the phenolic compounds and the hydrodeoxygenation of phenolic dimers to produce deoxygenated high-carbon-number hydrocarbons. (C) 2016 Elsevier B.V. All rights reserved.