Nanosized FeOx overlayers on Pt-skin surfaces for low temperature CO oxidation

Pt-Cu/carbon black catalysts were prepared by an impregnation-reduction method followed by acid leaching. The structure and composition of Pt-Cu nanoparticles treated under different conditions were investigated by inductively coupled plasma atomic emission spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. PtCu3 alloy formed upon annealing Pt-Cu/carbon black catalysts in H2. Acid leaching produced Pt-Cu nanoparticles consisting of Pt-skeleton surface structure and PtCu3 alloy core. The Pt-skeleton could be transformed to well-defined Pt-skin structure through further annealing the leached Pt-Cu nanoparticles in H2. Decorating the Pt-skin surfaces with Fe oxide nanopatches resulted in enhanced reactivity in the preferential oxidation of CO in excess H2. The tri-component Pt-Cu-Fe catalysts exhibited comparable activity to the bi-component Pt-Fe catalysts but used much less Pt.

The structural transformation of Pt-Cu catalysts upon reduction-leaching treatment is reported. Pt skin surfaces decorated with surface FeOx nanostructures exhibit enhanced reactivity in CO preferential oxidation and use less Pt than Pt-Fe catalysts.Figure optionsDownload as PowerPoint slide