K-V-Ca catalysts supported on porous alumina ceramic substrate for soot combustion: Preparation and characterization

摘要

The KCl, KNO3 CaCl2, Ca(NO3)2, V-Ca and K-V-Ca catalysts supported on alumina ceramic substrates have been prepared. X-ray diffraction and thermogravimetry/differential scanning calorimetry were used to characterize the catalysts, and their catalytic activities were evaluated by a soot oxidation reaction using the temperature-programmed reaction system. The catalytic activity of KNO3 is higher than KG, and the catalytic activity of Ca(NO3)2 is as much as that of CaCl2. The catalyst containing a higher KNO3 content exhibits CO2 adsorption, whereas higher CaCl2 and Ca(NO3)2 content can restrain the adsorption of CO2. The K-V-Ca catalyst with a molar ratio of 6:1:1 had the lowest soot onset combustion temperature. The melting and oxidation-reduction of KNO3, oxygen content of catalyst surface, and formation of some eutectic phase may be the key factors in improving catalytic activity of catalysts.