We developed an ultrasonic co-deposition technique to enhance the activity of Pt/C catalyst (and Pt/CNT, PtRu/C catalysts) for direct alcohol fuel cells (DAFCs) by CeO2 nanoparticles. The composite catalyst architecture is obtained by an ultrasonically mixing commercial Pt/C catalyst and CeO2 nanoparticles. Both Pt and CeO2 are dispersed uniformly in the electrodes resulting in a great deal of CeO2-Pt-C triple junction interfaces. Unlike traditional preparation of metal oxide supported Pt catalysts, CeO2 will not cut the connection between Pt and C in this composite catalyst structure. Electrochemical measurements confirm that CeO2 can improve almost all Pt based catalysts (Pt/C, Pt/CNT, and PtRu/C) for almost all small molecular alcohols (methanol, ethanol, ethylene glycol, and glycerol) electro-oxidation. EIS measurement shows that reaction resistance between Pt and alcohols is decreased much by adding small CeO2 nanoparticles. Besides, these composite catalysts have high stability. It proves CeO2 a very promising co-catalyst of Pt based catalysts for DAFCs. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.