Efficient hydrodeoxygenation of guaiacol to cyclohexanol over Ni–Co bimetallic nanoparticles supported on Al2O3–TiOx

Hydrodeoxygenation is currently an effective strategy for upgrading bio-oils. In this study, Al 2 O 3 –TiO x composite metal oxide was synthesized using the sol–gel method and then impregnated with Ni–Co bimetals for the selective hydrodeoxygenation conversion of lignin-derived phenolic compounds into cyclohexanol. The impact of different carriers and Ni Co metal content was investigated in detail, with the optimal 10Ni–5Co/Al 2 O 3 –TiO x achieving 93.7 % cyclohexanol yield by completely converting guaiacol within 2 h under mild reaction conditions of 200 °C and 1 MPa H 2 with isopropanol as the solvent. XRD and HRTEM analyses confirmed the presence of Ni and Co in an alloy form. XPS results indicated that the Ti synthesized by the sol–gel method primarily existed in the form of Ti 3+ , with suitable oxygen vacancies that could enhance substrate adsorption and conversion. The reaction pathway for the selective conversion of guaiacol to cyclohexanol was inferred based on the results of GC-MS analysis of byproducts.