Molybdenum oxide decorated Ru catalyst for enhancement of lignin oil hydrodeoxygenation to hydrocarbons

Herein, the catalysts of ruthenium and molybdenum oxide nanoparticles supported on activated carbon (AC) were synthesized by precursor stepwise impregnation and employed for the hydrodeoxygenation (HDO) of lignin oil. The XRD, TEM, XPS and NH3-TPD-MS result of RuMoOx/AC catalysts confirm that the method of loading molybdenum precursor before ruthenium precursor is advantageous for the MoOx and Ru nanoparticles high dispersion and the reduction of MoOx species enhance the amount of acidity of catalyst. Meanwhile, the reduction temperature of RuMoOx/AC-1-T catalysts could effectively regulate the MoOx species that determine the activity and product distribution of HDO. The conversion of aromatic monomers/dimers were up to 96% with high selectivity of hydrocarbon over RuMoOx/AC-1-350 catalyst at 160 °C and 30 bar H2. Which is attributed to the MoO3 and Ru species possess the excellent activity of benzene ring deep hydrogenation, ether bond breaking and acid dehydration. The RuMoOx/AC-1-350 catalyst effectively converted lignin oil (from the depolymerization of cornstalk hydrolysis residue) into hydrocarbons (56.9 wt%) and cyclohexanol/ethers (18.7 wt%) under 280 °C and 3 bar H2. The durability of the RuMoOx/AC-1-350 catalyst for HDO of lignin oil was also investigated and showed that the RuMoOx/AC-1-350 catalyst had good stability, regenerability and repeatability.