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

Abstract

Cordierite monoliths and alumina foams substrates were washcoated with PtCu/Al2O3 powder with a lowloading 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 between110?130 °C. The presence of platinum caused a synergistic effect on the Cu/Al2O3 catalyst, which greatly enhancedthe CO conversion. The most active catalyst reached 100% CO conversion at 110 °C, and proved hightolerance to CO2 and H2O in the feed. A good adherence between the catalytic film and the ceramic monolithicwalls was reached after preparation by the washcoating method and calcination at 300 °C. The macropores of themonolithic wall were covered by aggregates of 2?5 μm of PtCu/Al2O3 that filled the substrate cavities. Thehigher CO conversions obtained at low temperatures were probably due to the simultaneous formation of smallPt particles in close contact with copper species. In addition, XPS data showed metallic Pt0 and Cu0 particles onthe catalytic surface of the foam and monoliths. The bimetallic monoliths with low Pt loading, very active for theCOPrOx at low temperature in the presence of CO2 and H2O, are promising catalysts for practical applications.