Structural features and catalytic performance in CO preferential oxidation of MWCNT-supported Pt-Fe catalysts

Pt-Fe catalysts supported on multi-walled carbon nanotubes (MWCNT) were prepared by an impregnation method assisted with an ultrasonication treatment. The Pt-Fe/CNT catalysts were extensively examined for the preferential oxidation of CO in a H2-rich stream with respect to the influences of Pt/Fe ratios, different support materials and the presence of CO2 and water vapor in the feed stream. The optimized catalyst with a Pt/Fe ratio of 4/0.8 can attain complete CO conversion in a wider temperature range as well as favorable performance under the simulated reformatted gas mixture. It was noticed that the catalytic performance was greatly enhanced for the MWCNT-supported Pt-Fe catalysts in comparison with those supported on Al2O3, SiO2 and other carbon materials. Based on the structural features of the catalysts characterized by XRD, TGA, H2-TPR, TEM and Raman spectroscopy, the enhanced catalytic performance of Pt-Fe/CNT catalysts was discussed in terms of the interactions between Pt-Fe species and MWCNT, as well as the possible bifunctional surface with the presence of both Fe sites of Pt-Fe species and Pt sites.