Nanosized spinel oxide catalysts for CO-oxidation prepared via CoMnMgAl quaternary hydrotalcite route

Catalytic activity of the Co-Mn-Mg-Al mixed oxide spinel catalysts was examined in CO oxidation by O2. The prepared catalysts were characterized by chemical analysis (ICP), infrared spectroscopy (FTIR), thermal analysis (TG, DTG), powder X-ray diffraction (XRD), surface area measurements, and scanning electron microscopy (SEM).The calcined hydrotalcite-like precursor was composed of spinel-like Co-Mn-Mg-Al mixed oxide as the only XRD crystalline phases. The nanosized spinel oxide catalysts produced by calcination of hydrotalcites showed higher SBET than CoMn-hydrotalcite samples as calcination led to dehydroxylation and carbonate decomposition of anions in interlayer spaces. All the catalysts showed 100% CO conversion at high temperature even those calcined at 800 oC. A catalyst with Co/Mn = 4 and calcined at 500 oC showed 100% CO conversion at 160 oC. Moreover, this catalyst exhibited quite good durability without deactivation in 60 h stability test.