Engineering Co Nanoparticles Supported on Defect MoS_2–x for Mild Deoxygenation of Lignin-Derived Phenols to Arenes

To enhance the catalytic activity and temper the reaction conditions in the hydrodeoxygenation (HDO) of lignin-derived phenols to arenes, a Co–MoS_2–x catalyst was proposed and prepared via a facile strategy. Co oxide was synthesized via a solvothermal method, adsorbed at the edge of MoS_2–x, and finally reduced to metallic Co via an in situ spontaneous interfacial redox reaction to form Co–MoS_2–x. In the HDO of 4-methylphenol, a 97.4% conversion with toluene selectivity up to 99.6% is obtained at the hitherto lowest reaction temperature of 120 °C. This catalyst also exhibits good versatility in catalyzing HDO of different lignin monomers and even lignin bio-oil into arenes. Notably, Co–MoS_2–x is very stable in the HDO reusability study: no deactivation was observed after recycling eight times. The high HDO activity of Co–MoS_2–x is attributed to the formation of a metal–vacancy interface and electronic transfer from Co to MoS_2–x according to the characterization results and theoretical analysis.