In situ generated catalyst: copper(ii) oxide and copper(i) supported on Ca2Fe2O5 for CO oxidation

Abstract

Two sets of copper oxide–brownmillerite Ca₂Fe₂O₅ catalysts are prepared and studied for CO oxidation. The first set of catalysts is prepared by classical wet impregnation of the Ca₂Fe₂O₅ support. The second set is prepared by Ca₂Fe₂O₅ B-site doping. The active catalyst species are generated during hydrogen treatment. The two sets of catalysts behave very differently in CO oxidation. The performance of the impregnated catalysts is independent of the Cu content, while the performance of the doped catalysts can be tuned by the copper content. The best performing catalyst is a doped-reduced catalyst with 40 mol% Cu. Detailed characterization of the catalysts is carried out using nitrogen physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption fluorescence spectroscopy (XAFS).