Hydrodeoxygenation of heavy lignin bio-oil to oxygenated fuel catalyzed by Cu_xNi_y/MgO

Novel techniques for upgrading heavy lignin bio-oil, the phenolic oligomer from lignin depolymerization, are of great significance for achieving better utilization efficiency of carbon element in lignin. In this study, we pro-posed an efficient approach for producing high-quality oxygen-containing fuel from the renewable lignin bio-oil via the C-O bond cleavage and the subsequent hydrogenation over the Cu and Ni supported on alkaline MgO. Noticeably, the optimized Cu6Ni20/MgO resulted in inspiring yields of ethylbenzene (88.6%) and cyclohexanol (98.3%) from lignin dimers, and a colorless fuel with a high-heating value of 31.4 MJ kg-1 from the realistic lignin bio-oil. The results of catalyst characterization also unveiled that introducing Cu species reduced the formation of NiMgOx solid solution, which increased the content of Ni0 and consequently promoted the per-formance of upgrading lignin bio-oil. Furthermore, the recondensation of phenolic oligomers could be effectively restrained by the alkaline MgO. In addition, a plausible mechanism was proposed. Therefore, this work opens a promising avenue to designing efficient strategies for utilizing the heavy components from lignin depolymerization.