Hydrogen purification for fuel cells through CO preferential oxidation using PtCu/Al2O3 structured catalysts

Cordierite monoliths and alumina foams substrates were washcoated with PtCu/Al2O3 powder with a low loading of Pt (0.2 and 0.5 wt. %) and 4 and 8 wt. % of Cu in order to be used for the CO Preferential Oxidation (COPrOx) reaction. These catalysts exhibited a high performance in CO oxidation at temperatures between 110-130 degrees C. The presence of platinum caused a synergistic effect on the Cu/Al2O3 catalyst, which greatly enhanced the CO conversion. The most active catalyst reached 100% CO conversion at 110 degrees C, and proved high tolerance to CO2 and H2O in the feed. A good adherence between the catalytic film and the ceramic monolithic walls was reached after preparation by the washcoating method and calcination at 300 degrees C. The macropores of the monolithic wall were covered by aggregates of 2-5 mu m of PtCu/Al2O3 that filled the substrate cavities. The higher CO conversions obtained at low temperatures were probably due to the simultaneous formation of small N particles in close contact with copper species. In addition, XPS data showed metallic Pt-0 and Cu-0 particles on the catalytic surface of the foam and monoliths. The bimetallic monoliths with low N loading, very active for the COPrOx at low temperature in the presence of CO2 and H2O, are promising catalysts for practical applications.