Complete oxidation of CO and propene as model component of diesel exhaust and VOC using manganese oxide supported on octahedral (AlO63−)-Ce3+

Abstract

The complete oxidation of CO and propene as a model components of diesel engine exhaust and VOC have been investigated on a series of Ce doped MnOx/Al2O3 catalysts. The optimized MnOx/Al2O3 doped with 0.05 mol Ce showed higher CO and propene oxidation activity at 200 °C and 215 °C, respectively. The physicochemical properties of catalysts were analyzed by using XRD, RAMAN, NMR, H2-TPR, HRTEM and XPS techniques. The formation of Mn3O4 and Mn4+ species were observed on the catalyst surface. 27Al solid-state NMR showed the formation of octahedral [AlO63−]-Ce3+ species. These species were responsible for the donation of oxygen required for CO and propene oxidation. The adsorbed oxygen and oxygen vacancies were formed on the catalyst surface due to the synergistic interaction between Mn, Ce, and Al. The HRTEM results showed formation of well dispersed Mn over Ce-O-Al, and facilitated the proton abstraction required to activate the hydrocarbon. The mechanistic and kinetic aspects of CO and propene oxidation on catalyst surfaces have been reported in detail.