NO + CO reaction over LaCu0.7B0.3O3 (B = Mn, Fe, Co) and La0.8A0.2Cu0.7Mn0.3O3 (A = Rb, Sr, Cs, Ba) perovskite-type catalysts

Abstract

In this paper, catalytic reduction of NO by CO over perovskite-type oxides LaCu0.7B0.3O3 (B = Mn, Fe, Co) synthesized by sol–gel method was investigated. LaCu0.7Mn0.3O3 showed the highest activity among LaCu0.7B0.3O3 perovskite catalysts (88% CO conversion and 93% NO conversion at 350 °C). The effect of alkali and alkaline earth metals (Rb, Sr, Cs and Ba) on the structure and catalytic activity of LaCu0.7Mn0.3O3 perovskite catalysts was also investigated. The results showed that catalytic activity was improved by partial substitution of La by alkali and alkaline earth metals. The superior activity of La0.8Sr0.2Cu0.7Mn0.3O3 with respect to other catalysts (93% CO conversion and 96% NO conversion at 350 °C) was associated with a higher reducibility at low temperature, more oxygen vacancies and synergistic effect between Cu and Mn. The catalysts were characterized by XRD, BET, H2-TPR, XPS and SEM.