Catalytic activity of spinel oxides MgCr2O4 and CoCr2O4 for methane combustion

The chrome-containing spinels, MgCr2O4 and CoCr2O4, were prepared via sol-gel method using glucose as a complexing agent after calcination at 1400 degrees C and investigated as catalysts for catalytic combustion of methane. XRD indicated that single phase spinel oxides of MgCr2O4 and CoCr2O4 had formed. XPS analysis exhibited that Cr3+ was present in both catalysts, whereas a small amount of Cr6+ was only detected in MgCr2O4. The spinel MgCr2O4 proved to be very active and its catalytic activity reached T-10 = 400 degrees C and T-90 = 684 degrees C for methane combustion, which was much superior to that of CoCr2O4 (T-10= 480 degrees C and T-90 = 750 degrees C). Larger surface area (1.1 m(2)/g), more flexible reactive surface oxygen species, and appropriate surface and bulk structure of MgCr2O4 may contribute to its excellent catalytic activity toward methane combustion. (C) 2014 Elsevier Ltd. All rights reserved.