Efficient hydrodeoxygenation of lignin-derived phenolic compounds by using Ru-based biochar catalyst coupled with silicotungstic acid

Hydrodeoxygenation (HDO) is an effective technology for the conversion of bio-oil to high quality liquid fuels, in which an active and stable catalyst is crucial to gain a high reaction efficiency. In this work, a novel bifunctional catalyst of different Ru-based biochar catalyst coupled with silicotungstic acid (HSiW) was proposed to conduct the HDO of lignin-derived phenolic compounds under mild reaction condition. Ru/C-bamboo catalyst exhibited a better HDO performance than other Ru-based biochar catalysts and commercial Ru/C catalyst. Catalyst characterizations showed that Ru/C-bamboo catalyst possessed a rich mesoporous structure of 0.06 cm3/g mesopore volume and 0.07 cm3/g micropore volume, with a large specific surface area of 209 m2/g. A high metal dispersion and a good hydrogen adsorption ability were achieved in Ru/C-bamboo catalyst. And Guaiacol can be completely converted to cyclohexane with 87.7% selectivity at the temperature of 140 °C. Other typical phenolic compounds were also transformed into corresponding cycloalkanes with high yields above 90% in most cases. Besides, the lignin-oil also had a great improvement on the stability and the heat value after upgradation, with an increase of hydrocarbon content from 9.7% to 31.9%. This result indicated the potential of the bifunctional catalyst in the field of lignin-oil valorization.