The CO 2 absorption characteristics and catalytic oxidation activities of V/K and V/Ce/K-based catalysts for diesel soot oxidation

Abstract

The CO 2 absorption characteristics and catalytic oxidation activities of V/K and V/Ce/K-based catalysts were studied by temperature-programmed reactions. It was found that the V/K and V/Ce/K catalysts displayed a strong CO 2 absorption characteristic that was believed to be attributable to the formation of potassium bicarbonate species and physical CO 2 absorption. The experimental procedure used could precisely identify the soot ignition onset temperature (IOT) of the prepared catalysts. The V/K catalyst prepared at a V:K molar ratio of 1:2 showed the lowest IOT, but behaved a poor catalytic oxidation performance. The addition of CeO 2 into the V/K catalyst with a V:K molar ratio of 1:6 could reduce the IOT from about 320 to 303 °C at a loose soot/catalyst contact mode.