The influence on the structural and redox property of CuO by using different precursors and precipitants for catalytic soot combustion

Abstract

To gain fundamental understanding on the catalytic property of individual CuO for soot combustion, a series of CuO samples have been prepared with a simple precipitation method by using different Cu precursors and precipitants. Pure monoclinic CuO crystalline phase has been detected by XRD and Raman for all the samples. However, by changing the precursors and precipitants, the morphology and texture property of the CuO samples can be influenced. Furthermore, the redox property of the CuO catalysts can also be altered. Soot-TPR results have testified that four types of active sites with varied activity are present on the surface of all the samples, but only the two types of active sites that can be reduced by soot particles below 500 °C are believed to contribute effectively to soot combustion. It has been discovered that the surface oxygen mobility and abundance are the crucial factors to determine the soot combustion activity of CuO catalysts. Because of the optimal balance of these two factors, CuO-Cu(NO3)2-Na2CO3, a CuO catalyst prepared by the combination of Cu(NO3)2 precursor and aqueous Na2CO3 precipitant, displays the highest soot combustion activity among all the catalysts.