Iridium supported on MgF 2–MgO as catalyst for CO oxidation

Abstract

A combination of iridium catalytic phase and a new MgF 2–MgO support, obtained by the sol–gel method, has been shown to be an active catalyst for CO oxidation reaction. A series of catalysts containing 1 wt.% Ir were obtained by impregnation of MgF 2–MgO and pure MgF 2 or MgO supports with different precursors, i.e. H 2IrCl 6, Ir(acac) 3 and Ir 4(CO) 12. The surface areas and pore size distributions of the catalysts obtained were determined by the BET and BJH methods, respectively. Dispersion of iridium and the mean size of the crystallites were evaluated on the basis of hydrogen chemisorption. The activity of the catalysts in the CO oxidation reaction was measured. The effect of MgO content in the support and the influence of iridium precursor on the structure and activity of the iridium catalysts in the CO oxidation reaction were studied. The results show that the use of MgF 2–MgO support with 60 mol % content of MgO and the use of Ir(acac) 3 precursor lead to the catalyst with high surface area, high iridium dispersion and the best catalytic performance in CO oxidation.