The partial hydrogenation of benzene by a Pt nano-cluster/N-n-propyl chitosan hybrid membrane was investigated in this article. Monodispersed Pt nano-clusters were prepared by the reduction of H(2)PtCl(6) with ethylene glycol under microwave conditions. TEM, FTIR, XRD, (1)H-NMR, and XPS were used to characterize the structure of Pt nano-particles, N-n-propyl chitosan and Pt/N-n-propyl chitosan hybrid membrane, respectively. Experimental results showed that Pt/N-n-propyl chitosan hybrid membrane catalyst gave a high selectivity for cyclohexene of 85.2% in the liquid phase hydrogenation of benzene, while the selectivity of cyclohexene was only 58.2% over the Pt/chitosan hybrid membrane catalyst. It was worth noting that there was no cyclohexene in the product when the catalyst was only Pt nano-particles without chitosan hybrid membrane. So the chitosan or modified-chitosan membranes played an important role in the controlling to the hydrogenation of benzene, and the relationship of the swelling degree and the catalytic activity was discussed in detail. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2140-2146, 2012