IrFeOx/SiO2-A highly active catalyst for preferential CO oxidation in H-2

A novel bifunctional catalyst IrFeOx/SiO2, which was very active and selective for preferential oxidation of CO under H-2-rich atmosphere, was developed in this study. XRD, H-2-TPR, and chemisorption were applied to characterize three kinds of IrFeOx/SiO2 catalysts prepared by different impregnation sequences. The results indicated that both FeOx and Jr species were highly dispersed on the SiO2 support; the reduction of Ir species in the Fe-promoted Ir/SiO2 catalyst became easier than those in the Ir/SiO2, together with the partial reduction of Fe2O3; the saturation uptake of O-2 adsorption was greatly enhanced. In-situ DRIFTS, XPS, and Mossbauer techniques were further applied to detect the structural information on the selected Ir-FeOx/SiO2 catalyst prepared by co-impregnation method. A non-competitive adsorption catalytic mechanism was proposed where CO adsorbed on It sites and O-2 adsorbed on FeOx sites; the reaction probably took place at the interface of Ir and FeOx or via a spill-over process. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.