Catalytic Decomposition of N_2O over Mn_xCo_(3-x)O_4 Mixed Oxides and Modified Catalysts

A series of MnxCo3- xO4 spinel oxides with different compositions were prepared by co-precipitation met hod,and incipiently impregnated by alkali metal salt solutions to make modified catalysts for N2 O decomposition.The techniques such as X-ray diffraction( XRD),nitrogen physisorption( BET),Fourier transformed infrared( FTIR),scanning electron microscopy( SEM),hydrogen temperature-programmed reduction( H2-TPR) and X-ray photoelectron spectroscopy( XPS) were used to characterize these catalysts. The effects of mixed oxide compositions,additive types,and potassium precursors on catalysts structure and catalytic activity were investigated. It is shown that the addition of potassium and cesium onto Mn-Co mixed oxide resulted in the decrease in binding energies of Mn and Co elements and the weakening of Co—O and Mn—O bonds,thus the modified catalysts activity was enhanced. The most active catalyst for N2 O decomposition was K / Mn0. 4Co2. 6O4(K2CO3) catalyst,over which100% and 74. 2% conversion of N2 O can be maintained at 400 ℃ after continuous reaction for 50 h in oxygen-alone and oxygen-steam together,respectively.