Diesel soot oxidation catalyzed by Co-Ba-K catalysts: Evaluation of the performance of the catalysts

Abstract

Abstract The Co-Ba-K catalysts supported on alumina ceramic substrates were prepared. All the catalysts were characterized by X-ray diffraction and thermogravimetry/differential scanning calorimetry. The catalytic activities were evaluated by a soot oxidation reaction using the temperature-programmed reaction system. The catalytic activities of Co 3 O 4 , Ba(NO 3 ) 2 , Co-Ba, and Co-Ba-K catalysts were studied, and the effect of the contact mode on the soot onset ignition temperature and soot oxidation rate was also discussed. The soot onset ignition temperature is 373 °C for Co-Ba catalysts with molar ratios of 1:2, 1:1 and 2:1, which is the same as that of pure Co 3 O 4 . The Co-Ba catalysts containing KNO 3 can greatly lower the soot onset ignition temperature value. The catalytic activity of pure Co 3 O 4 and Ba(NO 3 ) 2 is affected by catalyst–soot contact intensity. The soot onset ignition temperature is not affected by contact intensity for the catalysts with proper Co-Ba-K ratios. The soot oxidation rate is greatly accelerated when the Co-Ba-K catalysts and soot are in the tight contact mode.