Hydrodeoxygenation of vanillin as model compound for pyrolysis oil over carboxylic carbon nanotubes-supported Ni catalysts

Abstract

Hydrodeoxygenation (HDO) is one of the most promising technologies for the biomass pyrolysis oil upgrading, but substantial challenges for the development of efficient HDO catalysts still remain. In this work, the nickel catalysts supported on carboxylic carbon nanotube (Ni/CCNTs-X, X = 1, 2, 3, 4 and 5) with different diameter have been synthesized for the HDO of model compound (vanillin) to p-creosol. As the tube diameters of Ni/CCNTs-X catalysts increased, the catalytic activity increased firstly, and then decreased. The conversion of vanillin over Ni/CCNTs-4 catalyst reached up to 90.0% under mild reaction condition, with a concomitant 87.7% selectivity of p-creosol. The transformation pathway for the HDO of vanillin over Ni/CCNTs-X catalysts involve in hydrogenation, hydrogenolysis and etherification.