Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process.The as-prepared nanoparticles can be directly used as hydrogenation nanocatalysts or as precursors to achieve efficient supported nanocatalysts.The surfaces of these nanoparticles are proposed to be encapsulated within a layer of organic modifiers,which are responsible for the enhancement of their solubility in organic solvents.The activated-carbon supported MoS2 nanocatalysts exhibit higher activity than the unsupported ones towards hydrogenation reactions of naphthalene,owing to the synergistic effects between nanoparticles and supports.The advantages of the present nanocatalysts,such as removal of conventional presulfiding requirements and reduction of nanoparticle aggregations,make them become promising applications in related petroleum chemical industry.