A composite anode comprising an outer and an inner catalyst layer is proposed to 1) suppress the ethanol crossover in direct ethanol fuel cell (DEFC), and 2) improve the cell performance as well as the utilization efficiency of ethanol fuel. The inner catalyst layer contains a thin layer of Pt-50-Sn-50 nanoparticles directly deposited on the Nafion (R) membrane surface through impregnation-reduction (IR) method, and acts as the reactive ethanol filter in this paper, several aspects of the research are reported First, the mitigation of ethanol crossover and the performance of membrane electrode assembly (MEA) of the proposed structure are compared to those with normal structure. Next, a candidate mechanism of the mitigation of ethanol crossover and the improvement of MEA performance is investigated Third, SEM, X-ray, EDS and EPMA analysis are used to characterize microstructures, phases, chemical composition and distributions of the obtained Pt-50-Sn-50 layer. Finally, the ethanol crossover rate in a DEFC is determined through measuring the CO2 concentration at the cathode exhaust in real time Experimental results demonstrate that the composite anode with an inner layer of Pt-50-Sn-50 nano-catalyst particles on Nafion membrane surface suppresses ethanol crossover up to 17% more than the anode without the inner layer, and yield a 6% better MEA performance than the normal-MEA The inner Pt-50-Sn-50 catalyst layer serves both as an ethanol filter and an electrode Its dual-role contributes to the suppression of ethanol crossover, and improvement of both cell performance and the utilization efficiency of ethanol fuel, both of which are dependent on the catalyst activity of the ethanol electro-oxidation over the thin catalyst layer directly deposited on Nafion membrane surface (C) 2009 Professor T. Nejat Veziroglu Published by Elsevier Ltd All rights reserved