Pt supported on a carbon molecular sieve (Pt/CMS) was prepared by pyrolysis of polyfurfuryl alcohol containing pre-reduced Pt particles. The catalysts were characterized by hydrogen chemisorption, XRD, N-2 adsorption/desorption and TEM. Hydrogen chemisorption showed that not all the Pt particles were exposed to H-2 molecules. Oxidation treatment made Pt particles more accessible to H-2. Catalyst activity was evaluated by hydrogenation of 1-hexene. Hydrogen spillover was demonstrated by diluting Pt/CMS with activated carbon or hydrogen type zeolite Y. The initial conversion of 1-hexene was increased from 86.5% to 98.5% and to 100% when Pt/CMS was diluted with activated carbon and hydrogen type zeolite, respectively. The high initial conversion was sustained for 6 It in the presence of diluents while the conversion decreased quickly for Pt/CMS alone. Crown Copyright (C) 2007 Published by Elsevier B.V. All rights reserved.