Diesel soot combustion on potassium promoted hydrotalcite-based mixed oxide catalysts

KNO3 or K2CO3 supported Mg–Al hydrotalcite-based mixed oxide catalysts were investigated for the catalytic combustion of diesel soot. The activity of the catalysts before and after reactions with soot was conducted under the flow of air and high purity He gas. It has been found that K shows a great promotion of the catalytic activity, and deactivation was not detected after the reaction with soot in a muffle furnace in a static air atmosphere. The active phases were examined by XRD. The high activity is found to be due to an interaction between K and Mg(Al), which may weaken the Mg(Al)–O bonds, thus facilitating the mobility of the O species.