Sulfur vacancy interface synergistically regulated Co-MoS2-x catalysts for hydrodeoxygenation of lignin model compounds to aromatics

The selective conversion of lignin-derived oxygenated aromatics into aromatic hydrocarbons represents an important strategy for improving the value-added utilization efficiency of biomass. However, this process generally suffers from the intrinsic difficulty of cleaving aryl C-O bonds and the tendency of aromatic rings to undergo excessive hydrogenation. To address these challenges, we developed a Co-MoS 2-x catalyst based on an acid-etching engineering strategy for molybdenum sulfide. By introducing HCl during the hydrothermal synthesis process to regulate the reaction environment, both the generation of sulfur vacancy defects in MoS 2 and the interfacial electronic structure were simultaneously modulated, thereby yielding a layered molybdenum sulfide-based catalyst with tunable sulfur vacancies and interfacial electronic properties. Under conditions of 230 °C, 1 MPa H 2 , and 30 min, the acid-etched Co-MoS 2-x catalyst prepared at pH 1 achieved a diphenyl ether hydrodeoxygenation conversion of >99.9% and a benzene selectivity of 98.4%, while maintaining good stability over five consecutive cycles and exhibiting broad applicability toward a range of lignin-derived ether and phenolic substrates. The results demonstrate that acid etching at an appropriate pH increases the concentration of sulfur vacancy defects and promotes the formation of active Co-Mo-S interfacial sites, which in turn enhances the adsorption and activation of reactant molecules.