Ce-Doped Co-ZIF as an efficient catalyst for hydrodeoxygenation of lignin-derived phenols: From guaiacol to cyclohexanol

Through the utilization of diverse technological processes, lignin could be transformed into a multitude of valuable chemicals and fuels. This transformation not only reduces our dependence on fossil energy but also fosters the promotion of environmental sustainability. In this study, Ce metal was incorporated into the zeolite imidazolium framework-67 (ZIF-67) using the impregnation method to prepare a series of bimetallic catalysts. Using isopropanol solvent as the hydrogen source, guaiacol was effectively converted to cyclohexanol with over 80.0% selectivity over the optimum catalyst at 240 °C, 1.5 MPa N2, for 4 hours. The prepared catalysts were subjected to characterization methods such as BET, SEM, XPS, TEM, XRD, H2-TPR and NH3-TPD. The results of the characterization show that the addition of Ce changed the zeolitic imidazolium ester backbone structure of ZIF-67 and encouraged the emergence of more oxygen vacancies, which strengthened the catalyst hydrodeoxygenation activity and reducibility. Based on the findings of the catalytic performance tests and a retesting, the reaction pathway of the guaiacol hydrodeoxygenation process was suggested.