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The hydrogen which feed PEM fuel cells should contain less than 10 ppm of CO in order to notdeteriorate the anode of the cell. One of the main ways to obtain hydrogen is by means ofhydrocarbons or alcohols reforming, followed by the water gas shift reaction. After these steps, rich-hydrogen stream contains around 1% CO, so a further CO elimination stage is needed. In this sense,the CO Preferential Oxidation (COPrOx) is a promising alternative to decrease CO concentration [1].Taking into account the excellent properties of noble metal for the CO oxidation reactions aswell as the important role of a transition metal as a second metal, a series of PtCu/Al 2 O 3 monolithswith low Pt loading have been prepared over cordierite substrate [2, 3]. Then, they were evaluated inthe COPrOx reaction and characterized by means of different techniques.Four monoliths containing PtCu/Al 2 O 3 catalysts with 0.5 and 0.2 wt. % Pt, and 4 and 8 wt. % Cuwere prepared by the washcoating method. The aqueous slurries were prepared from the powdercatalysts which have been synthesized previously by wet impregnation of Cu (II) nitrate and Pt (II)tetraaminenitrate solution on Al 2 O 3 . Several cycles involving impregnation, drying and calcinationwere carried out in order to obtain an adequate layer of catalyst over cordierite substrate. The resultingmonoliths were named Pt(0.5)Cu(8)-M, Pt(0.5)Cu(4)-M, Pt(0.2)Cu(8)-M and Pt(0.2)Cu(4)-M, wherethe numbers between parentheses indicate the metal content (wt. %).The monolithic catalysts were evaluated for the COPrOx reaction under the followingconditions: 1% CO, 1 % O 2 , 40 % H 2 and He. W/F: 2.1 mgcm -3 min. Before catalytic evaluation, themonoliths were reduced with a H 2 /He stream at 300 °C during two hours. The catalytic results areshown in Figure 1.