The graphitic carbon strengthened synergetic effect between Pt and FeNi in CO preferential oxidation in excess hydrogen at low temperature

Abstract

A variety of PtFeNi catalysts supported on carbon materials have been prepared and tested for CO preferential oxidation (PROX) in excess hydrogen. 100% O₂ and CO conversions have been achieved over carbon black (CB) and carbon nanotube (CNT) supported PtFeNi catalysts at room temperature in a feed gas containing 1% CO, 0.5% O₂ (volume ratio) and H₂ balance gas. N₂ adsorption, temperature-programmed desorption (TPD) and transmission electron microscopy (TEM) studies indicate that the carbon textural properties and surface chemistry determine the catalyst particle size distribution and mean size; but the mean particle size does not have a great influence on the catalytic performance within the investigated particle size range. X-ray diffraction (XRD), resistance measurements and the designed catalytic reaction results reveal the ability of graphitic carbon to capture and shuttle electrons from the noble metal to spatially different sites in the FeNi species through the π–π network, enables the indirect interactions between Pt and the FeNi species, leading to a strengthened synergistic effect, enhancing the CO oxidation activity at room temperature, increasing the Pt utilization efficiency, and apparently decreasing the Pt loading level.