Catalytic combustion of methane over La2TM0.3Zr1.7O7-δ (TM = Mn, Fe, and Co) pyrochlore oxides

La2Zr2O7 and La2TM0.3Zr1.7O7-delta (TM = Fe, Mn, and Co) pyrochlores were investigated as catalysts for methane combustion at moderate-high temperatures. They were prepared by the coprecipitation method and characterized by XRD, DSC, H-2-TPR, IR, and N-2 adsorption/desorption techniques. The introduction of transition metals strongly influences the Zr-O bond strength, the temperature of pyrochlore phase formation, the redox properties, and crystallite size of pyrochlores. Among the catalysts tested, La2Fe0.3Zr1.7O7-delta gives the highest catalytic activity. The catalytic activities of La2TM0.3Zr1.7O7-delta pyrochlore oxides for methane combustion were mainly dependent on the textural properties (BET area, crystallite size). Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.