Chemical-physical properties of spinel CoMn2O4 nano-powders and catalytic activity in the 2-propanol and toluene combustion: Effect of the preparation method

Spinel-type CoMn(2)O(4)nano-powders are prepared using sol-gel auto combustion (SGC) and co-precipitation (CP) methods and their catalytic activities are evaluated in combustion of 2-propanol and toluene. The chemical-physical properties of the oxides are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N-2-adsorption-desorption, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). After calcination at 700 degrees C, CoMn2O4-SGC shows higher amounts of the normal-type spinet phase and is more crystalline than CoMn2O4-CP. Higher calcination temperatures (850 degrees C) do not affect very much the weight percentage of the normal-type spinel phase; although the crystal size slightly increased. The TPR analysis evidences a large number of Mn3+ cations in CoMn2O4-SGC compared to CoMn2O4-CP. This difference, together with the higher surface area, could justify the higher activity of CoMn2O4-SGC in both the investigated reactions.