Efficient Hydrodeoxygenation of Lignin-Derived Phenolic Compounds Over Ru-Based Catalyst with Biochar and Al2O3 as Composite Support

Graphical This work proposed a novel and stable Ru-based catalyst with biochar and Al 2 O 3 as composite support, which achieved an outstanding performance on the hydrodeoxygenation of lignin-derived phenolic compounds and raw lignin-oil. Under the catalysis of optimized Ru/C-Al 2 O 3 catalyst, the hydrocarbon content increased significantly from 10.7 % to 95.7 % at 230 °C. Hydrodeoxygenation (HDO) is a common strategy for upgrading lignin-derived phenolic compounds into high-quality liquid fuels, and the support rational design of HDO catalysts is critical to achieve a good reaction performance. This work proposed a novel Ru-based catalyst with biochar and Al 2 O 3 as composite support. The addition of biochar can enlarge the porous structure, and the addition of Al 2 O 3 can enhance the acid property of the support. By regulating the content of biochar and Al 2 O 3 components, Ru/CA-2 catalyst achieved the best HDO performance of lignin-derived phenolic compounds, with the optimal component balance of 50 %C and 50 %Al 2 O 3 . This catalyst possesses the high Ru metal dispersion (1.38 nm particle size) to activate the hydrogen source, the moderate acid property to suppress carbon deposition and the abundant oxygen vacancy to promote substrate adsorption at the same time. 99.9 % conversion of guaiacol is obtained at 230 °C, with 99.9 % selectivity towards cyclohexane. Ru/CA-2 catalyst also has a good recyclability, with no obvious activity loss after five runs. Furthermore, in the application of catalytic lignin-oil HDO, the content of hydrocarbons increase from 10.7 % to 95.7 %, showing great potential on the industrial usage.