High catalytic performance of Pt-Fe alloy nanoparticles supported in mordenite pores for preferential CO oxidation in H2-rich gas

Catalytic performance of Pt-Fe/mordenite for preferential CO oxidation (PROX) was tested in comparison with that of Pt-Fe/Al2O3. The former catalyst pretreated at 300 °C (Pt-Fe/M-300) showed extremely high reactivity and selectivity for the PROX reaction but the catalyst treated at 500 °C (Pt-Fe/M-500) showed the inferior performances as well as Pt-Fe/Al2O3. Characterization of the catalysts indicated that most of metallic particles at Pt-Fe/M-300 were supported in the mordenite cages, whereas the particles at Pt-Fe/M-500 were supported outside. It was also found that the catalyst particles in the cages of the Pt-Fe/M-300 have ca. 10 times higher surface area than that of outside and can adsorb CO selectively, compared with H2, but not at Pt-Fe/M-500. Such a difference in the above specific properties of Pt-Fe/M-300 from the others is presumably the reason why it exhibits the superior PROX performance. Complete CO elimination was demonstrated at 150 °C in a synthesized gas mixture of 1% CO, 1% O2, 20% CO2, 20% H2O and H2 balance on Pt-Fe/M-300 and no noticeable degradation of the performances was done for 24 h, indicating the potential of practical application of the catalyst to a fuel processor for polymer electrolyte fuel cells.