Improvement of catalytic performance of preferential oxidation of CO in H2-rich gases on three-dimensionally ordered macro- and meso-porous Pt-Au/CeO2 catalysts

Three-dimensionally ordered macro- and mesa-porous (3DOM) M/CeO2 (M = Pt, Au and Pt-Au) catalysts supported with different noble metal nanoparticles of Pt, Au and Pt-Au alloy were synthesized by thermal decomposition of cerium nitrate precursor using the close packed structures of PS colloidal crystals as templates. The obtained 3DOM M/CeO2 catalysts possess well-defined 3DOM skeletons composed of ultrafine CeO2 nanoparticles. The macroporous CeO2 skeletons contain the mesoporous walls possessing the nanopores of similar to 3-4 nm and the noble metal nanoparticles of Pt, Au, and Pt-Au alloy with the grain sizes of similar to 5.0 nm homogenously dispersed. The catalytic performance of CO preferential oxidation (PROX) in H-2-rich gases on 3DOM Pt/CeO2, Au/CeO2, and Pt-Au/CeO2 catalysts were systematically studied. The superior catalytic performance with 90% CO conversion and 83% CO2 selectivity are realized on 3DOM 1 wt.% Pt1Au1/CeO2 catalyst at 80 degrees C under the weight hourly space velocity of 30,000 mL g(-1) h(-1). Moreover, the 3DOM 1 wt.% Pt1Au1/CeO2 catalyst exhibits excellent catalytic stability maintaining 90% CO conversion and 56% CO2 selectivity even after the test period of 260 h under the same flow rate. The three-dimensionally ordered macro- and mesa-porous skeletons, the synergistic effect due to the formation of Pt-Au alloy, and the strong interaction of Pt-Au alloy nanoparticles with CeO2 supports are identified to be beneficial to the improvement of catalytic activity and stability of CO PROX. The obtained 3DOM Pt-Au/CeO2 catalysts may be potential candidates with the improved catalytic performance of CO PROX reaction in H-2-rich gases for polymer electrolyte membrane fuel cells (PEMFCs) applications. (c) 2013 Elsevier B.V. All rights reserved.