Synthesis of mixed oxides AMn2O4 (Co, Cu and Ni) prepared by auto combustion to control emissions of volatile organic compounds

ABSTRACT Volatile organic compounds (VOCs) have a high vapor pressure and low water solubility and are recognized either as major contributors of air pollution either, through their toxic nature, or as precursors of ozone and photochemical smog. The objectives of this work were to synthesize several manganite oxides under the same preparation conditions and the study of their properties and activities to develop as friendly environmental catalysts in oxidation of toluene, the VOC more abundant in the Earth's atmosphere. AMn2O4 (A=Co, Ni, Cu) manganite spinels were prepared by using by using auto combustion method under the same synthesis conditions and their physico-chemical properties were studied by XRD, BET, FTIR and MEV. The relationship between the properties and activity of spinels in oxidation of toluene was investigated. Among all, Cu and Co catalysts exhibited the most promising activity, converting 92 and 99%, respectively. The higher activity was explained in terms of the possible synergetic effect between Mn3+ and Co2+, Cu2+ phases in that manganite oxides. No direct relationship was resulted between activity with either specific surface area.