The CO2 absorption characteristics and catalytic oxidation activities of V/K and V/Ce/K-based catalysts for diesel soot oxidation

The CO2 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 CO2 absorption characteristic that was believed to be attributable to the formation of potassium bicarbonate species and physical CO2 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 CeO2 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.