Simultaneous control of NOx-soot by substitutions of Ag and K on perovskite (LaMnO3) catalyst

Abstract

The different Ag and K substituted perovskite catalysts including base catalyst were LaMnO3 by the solid state method and the diesel soot was prepared in the laboratory. Their structures and physico-chemical properties were characterized by X-ray diffraction (XRD), BET, SEM, H2-TPR, and XPS tech-niques. The Ag Substituted at A-site perovskite structured catalysts are more active than other type of catalysts for the simultaneous soot-NOx reaction, When Ag and K are simultaneously introduced into LaMnO3 catalyst, soot combustion is largely accelerated, with the temperature (Tm) for maximal soot conversion lowered by at least 50 °C, moreover, NOx reduction by soot is also facilitated. The high ac-tivity of La0.65Ag0.35MnO3 perovskite catalyst is attributed to presence of metallic silver in the catalyst. The activity order of Ag doped LaMnO3 is as follows La0.65Ag0.35MnO3 > La0.65Ag0.2MnO3 > La0.65Ag0.4MnO3 > La0.65Ag0.1MnO3. The dual substitution of silver and potassium in place of La in LaMnO3 gives better activity than only silver doped catalyst. In a series of La0.65AgxK1-xMnO3, the opti-mum substitution amount of K is for x=0.25. The single and doubled substituted perovskite catalyst proved to be effective in the simultaneous removal of NOx and soot particulate, the two prevalent pol-lutants in diesel exhaust gases in the temperature range 350-480 °C. Copyright © 2018 BCREC Group. All rights reserved.