Catalytic combustion of lean methane at low temperature over ZrO2-modified Co3O4 catalysts

A series of ZrO2 modified Co3O4 catalysts prepared by co-precipitation method were characterized by XRD, Raman, SEM, XPS and H2-TPR, and used in the catalytic combustion of lean methane at low temperature. XRD and Raman results demonstrate that ZrO2Co3O4 is in the form of a Zr-Co-O solid solution. XPS result indicates that the content of ZrO2 in ZrO2Co3O4 composite oxide has a significant influence on the concentration of Co2+ in tetrahedral site (ATetrahedral/AOctahedral) and the surface active oxygen species, which are correlated to the activity of methane combustion. H2-TPR result shows that the ZrO2(2)-Co3O4 composite oxide exhibits better reducibility. Compared with pure Co3O4, the ZrO2(2)-Co3O4 composite oxide presented the highest activity with T90 of 335 °C. All these characterizations suggest that high activity in the lean methane combustion could be ascribed to high surface areas, ATetrahedral/AOctahedral and surface active oxygen species.