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

Abstract

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.