Methane combustion over supported cobalt catalysts

A series of cobalt-based catalysts with different supports have been prepared using impregnation method, and characterised by X-ray diffraction (XRD), laser Raman (LR), and infrared spectroscopy (IR). The catalytic activities for methane combustion were assessed in a micro-reactor. The ZrO2 and Al2O3 supports are themselves active in methane combustion, and ZrO2 supported cobalt catalyst was found to have the highest activity amongst the TiO2, Al2O3, MgO supported catalysts and bulk Co3O4. The Co content has a marked effect on the activity of the ZrO2 supported catalyst with 1.0 and 15 wt.% of Co having the lowest light-off temperature in methane combustion. In the MgO supported catalyst, Co oxide was highly dispersed over the MgO support surface or enters the lattice of MgO to form a solid solution, whose activity for methane combustion is reasonable. The zirconia supported cobalt catalysts are very active and stable when calcination or reaction temperature is no more than 900 degreesC. Calcining the catalysts at temperatures above 900 degreesC for more than I h decreases the catalyst activity. The deactivation of the catalyst probably results from the decrease of the surface area. (C) 2001 Elsevier Science B.V. All rights reserved.