This study used a simple and easy method to prepare a highly dispersed Ag nanoparticles (NPs) on modified carbon nanotubes (MCNTs). The Ag NPs were easily attached to the MCNT support by anchoring them to the functional groups. Oxygen functionalities on the HNO3-activated MCNT wall (FCNTs) provide nucleation centers for metal ions and can stabilize metal NPs on the support surface. This is an essential process for obtaining highly dispersed Ag NPs on FCNTs due to the presence of surface oxygen-containing functional groups. In addition. an Ag NP active site with a smaller particle size and higher dispersion rate exhibits higher activity for CO oxidation at low reaction temperatures. The catalytic results suggest that the Ag/FCNTs catalysts have a high potential for application in low-temperature CO oxidation. (C) 2011 Elsevier B.V. All rights reserved.