Na+-intercalated carbon nanotubes (Na-CNTs) were obtained by impregnation of CNTs with sodium acetate followed by annealing at high temperatures under argon. Stable NaCNTs-supported Pt catalysts (Pt/Na-CNT catalysts) were then prepared for hydrogen purification via preferential CO oxidation in a H-2-rich stream (CO-PROX). Characteristic studies show that the content of Na+ species in CNTs is increased with increased annealing temperature and the Pt nanoparticles with an average size of 2-3 nm are uniformly dispersed on the surfaces of Na-CNTs. An optimized Pt/Na-CNT catalyst with 5 wt% Pt loading can completely remove CO from 40 degrees C to 200 degrees C. This catalyst also exhibits long-term stability for 1000 h at 100 degrees C in feed gas containing 1% CO, 1% O-2, 50% H-2, 15% CO2, and 10% H2O balanced with N-2. The electron transfer between the Pt nanoparticles and Na+ species plays an important role in enhancing the CO-PROX performance of the catalyst. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.