Selective hydrodeoxygenation of guaiacol to cyclohexanol over core-shell Cox@C@Ni catalysts under mild condition

Abstract

Guaiacol, a typical lignin-derived phenolic compound, can be converted to high value-added cyclohexanol through hydrodeoxygenation (HDO). In this work, a series of core-shell Cox@C@Ni catalysts were prepared via two-step hydrothermal and calcination treatments, and applied to catalyze guaiacol to cyclohexanol. Compared with Co@C catalyst, core-shell Cox@C@Ni catalysts exhibited much better catalytic performance. Almost 100% guaiacol conversion and 90% cyclohexanol selectivity were achieved over Co1.2@C@Ni catalyst at 220 °C, 0 MPa N2 for 2 h using isopropanol as H-donor solvent, which was carried out under much milder conditions compared with previous research. The structure feature of core-shell Cox@C@Ni catalysts were analyzed by BET, XRD, SEM, TEM, HRTEM, etc. The catalyst compositions and acidities played a significant role on hydrodeoxygenation of guaiacol via ICP and NH3-TPD analysis. The influences of reaction temperature, reaction time and initial nitrogen pressure were also investigated to explore the optimal reaction condition. Moreover, the possible reaction pathways and reaction mechanism was deduced based on the product distributions and physicochemical properties.