Engineering Co nanoparticles supported on defect MoS2–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–MoS2–x catalyst was proposed and prepared via a facile strategy. Co oxide was synthesized via a solvothermal method, adsorbed at the edge of MoS2–x, and finally reduced to metallic Co via an in situ spontaneous interfacial redox reaction to form Co–MoS2–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–MoS2–x is very stable in the HDO reusability study: no deactivation was observed after recycling eight times. The high HDO activity of Co–MoS2–x is attributed to the formation of a metal–vacancy interface and electronic transfer from Co to MoS2–x according to the characterization results and theoretical analysis.