Hydrodeoxygenation of phenolic compounds and lignin pyrolysis oil for the production of cyclohexanes over core-shell Ru@SiO2-ZrO2 catalyst with high stability

Hydrodeoxygenation (HDO) technology is an essential method for efficiently converting phenolic compounds from biomass into high-quality liquid fuels. Rationally designed catalysts not only significantly enhance stability and reaction rates, but also improve product selectivity and fuel quality. In this study, we proposed a Zr 3+ -defect-rich core–shell structured catalyst Ru@SiO 2 -ZrO 2 and employed it for the HDO of phenolic compounds and lignin pyrolysis oil. Ru nanoparticles are uniformly dispersed and have small particle sizes, showing outstanding catalytic hydrogenation activity. The porous SiO 2 shell possesses a high specific surface area with a high thermal stability, facilitating reactant transport and maintaining catalyst structural integrity. ZrO 2 serves as an acid modifier to enhance the catalyst acidity and promote the deoxygenation procedure. Besides, ZrO 2 enhances the adsorption of phenolic compounds and improves the cleavage of C-O bonds, due to its abundant oxygen vacancies . These factors make the catalyst achieved complete conversion of guaiacol to cyclohexane at mild reaction temperature of 240°C, which is superior to other similar reported results. Compared to conventional supported Ru/SiO 2 -ZrO 2 catalysts, the unique core–shell structure of Ru@SiO 2 -ZrO 2 obtained a sustained catalytic activity after five consecutive recycles without significant deactivation. Moreover, this core–shell catalyst exhibited good HDO performance for various phenolic compounds and lignin pyrolysis oil. The hydrocarbon content increased significantly from 12.7 % to 96.9 % in the upgrading of lignin pyrolysis oil, demonstrating the catalyst’s great potential for future industrial applications.