Hydrodeoxygenation of lignin-derived phenolic compounds over Ru/TiO2–CeO2 catalyst prepared by photochemical reduction method

Abstract Hydrodeoxygenation (HDO) is an important pathway for lignin-oil upgradation to produce high quality liquid fuels, in which the high-active catalyst is the key point to achieve a high HDO efficiency. In this study, Ru/TiO2, Ru/CeO2 and Ru/TiO2–CeO2 catalysts were synthesized by a novel photochemical method with a high Ru dispersion and used for the HDO of lignin-derived phenolic compounds. Among these three catalysts, Ru/TiO2–CeO2 showed a better performance than Ru/TiO2 and Ru/CeO2. And guaiacol was transformed into cyclohexane with conversion and product selectivity close to 100 % at 230 °C under 1 MPa hydrogen atmosphere. Ru/TiO2–CeO2 took the advantages of Ru/TiO2 and Ru/CeO2, namely high Ru metal dispersion, plenty of medium strength acid sites and abundance of oxygen vacancy, which promoted the guaiacol adsorption and the HDO catalytic activity. Moreover, Ru/TiO2–CeO2 catalyst showed an effective upgrading of other lignin-derived phenolic compounds. And the lignin-oil also enabled to be upgraded efficiently, producing a high content of hydrocarbons and alkylphenols.