Ru<sub>0.05</sub>Ce<sub>0.95</sub>O<sub>2</sub> Solid Solution Derived Ru Catalyst Enables Selective Hydrodeoxygenation of m‐Cresol to Toluene
Desen Fu, Xiaoxia Wu, Beilei Cui, Yonghua Guo, Hua Wang, Jinyu Han, Qingfeng Ge, Xinli Zhu
Abstract
Abstract Selective hydrodeoxygenation (HDO) of biomass lignin‐derived phenolic compounds to aromatics is a demanding reaction. Oxophilic Ru based catalysts can catalyze direct deoxygenation but suffer from competing C−C hydrogenolysis to CH 4 at 350 °C and hydrogenation of phenyl ring at 250 °C under atmospheric pressure. In this work, a solid solution Ru 0.05 Ce 0.95 O 2 catalyst was hydrothermally synthesized, characterized and tested for HDO of m‐cresol. The Ru species is highly dispersed in the solid solution as isolated atoms and/or subnanometer clusters as a result of strong Ru−O−Ce interaction, and the catalyst shows high concentration of oxygen vacancies. In contrast to nonselective Ru/SiO 2 , Ru 0.05 Ce 0.95 O 2 selectively catalyzes deoxygenation to toluene while significantly inhibits C−C hydrogenolysis and hydrogenation. Moreover, the overall intrinsic HDO rate on Ru 0.05 Ce 0.95 O 2 is 2.2 and 8.8 times higher than those on Ru/CeO 2 and Ru/SiO 2 , respectively. The Ru−O V −Ce sites were proposed to be the active sites for deoxygenation. Inhibition of C−C hydrogenolysis and phenyl hydrogenation can be ascribed to the reduced size of the Ru ensembles due to the strong interaction in the solid solution.