Catalytic Hydrodeoxygenation of Guaiacol to Cyclohexanol over Bimetallic NiMo-MOF-Derived Catalysts

Abstract

Lignin is an attractive renewable source of aromatics with a low effective hydrogen to carbon ratio (H/Ceff). The catalytic hydrodeoxygenation (HDO) of lignin-derived model compounds is a key strategy for lignin upgrading. In this work, the HDO of guaiacol, a typical lignin-derived compound, was carried out over metal–organic framework (MOF)-derived Ni-based catalysts. A monometallic Ni-MOF catalyst and different ratios of bimetallic NiMo-MOF catalysts were synthesized by a hydrothermal process, followed by a carbonization process. Among these catalysts, Ni3Mo1@C exhibited an excellent catalytic performance, affording a guaiacol conversion of 98.8% and a cyclohexanol selectivity of 66.8% at 240 °C and 2 MPa H2 for 4 h. The addition of Mo decreased the particle size of the spherical structure and improved the dispersion of metal particles. The synergistic effect between Ni and Mo was confirmed by various means, including ICP, XRD, SEM, TEM, and NH3-TPD analyses. In addition, the effect of the reaction temperature, time, and H2 pressure during the HDO process is discussed in detail.