A series of diphenyl-sulfide(Ph_2S)-immobilized Pd/C catalysts(Pd-Ph_2S_((X))/C) were prepared using the wetness-impregnation and immobilization method.Pd-Ph_2S_((x))w/C catalysts employed for the hydrogenation of o-chloronitrobenzene showed very high selectivity.The structure of Pd-Ph_2S_((x))/C with different molar ratio of ligand(x-values) was characterized by XPS and TG-DSC-MS.The results suggest a “saturated” surface ratio of Ph_2S/Pd(about 0.3) was formed on the Pd-Ph_2S_((x))/C catalysts surface.The Ph_2S immobilized on the Pd particle is quite stable,and the desorption of Ph_2S or dissociative loss of phenyl group was only found at temperatures above 500 K.The possible catalytic mechanism of the Pd-Ph_2S_((x))/C catalyst was also discussed. A series of diphenyl-sulfide (Ph 2 S) -immobilized Pd / C catalysts (Pd-Ph 2 S _ ((X)) / C) were prepared using the wetness-impregnation and immobilization method. Pd-Ph_2S _ ((x)) w / C catalysts employed for the hydrogenation of o-chloronitrobenzene showed very high selectivity.The structure of Pd-Ph_2S _ ((x)) / C with different molar ratio of ligand (x-values) was characterized by XPS and TG-DSC-MS.The results suggesting that the “saturated” surface ratio of Ph_2S / Pd (about 0.3) was formed on the Pd-Ph_2S _ ((x)) / C catalyst surface.The Ph_2S immobilized on the Pd particle is quite stable, and the desorption of Ph_2S or dissociative loss of phenyl group was only found at temperatures above 500 K. The possible catalytic mechanism of the Pd-Ph 2 S _ ((x)) / C catalyst was also discussed.