Simultaneous NO Reduction and Hg0 Oxidation over La0.8Ce0.2MnO3 Perovskite Catalysts at Low Temperature

Abstract

La1–xAxMn1–yByO3 (A = Ca, Sr and Ce, B = Cu, Co and Fe, x = 0/0.2, y = 0/0.2) perovskite catalysts were employed for simultaneous NO and Hg0 removal. The perovskite structure is beneficial for low temperature catalysis. The substitution of A-site cations with cerium (Ce) cations significantly improved the catalytic activity of perovskite catalyst. 90% NO conversion and 98% Hg0 oxidation was attained using La0.8Ce0.2MnO3 catalyst at 200 °C. Hg0 oxidation posed negligible effect on NO reduction. Compared to the N2 plus 4% O2 atmosphere, Hg0 oxidation was significantly facilitated by selective catalytic reduction atmosphere. The enhancement in Hg0 oxidation was probably attributed to NO2 originated from NO. Furthermore, a possible reaction mechanism was proposed, in which surface oxygen, Mn4+ and Ce4+ contributed to NO and Hg0 removal. Such knowledge provides useful information for the development of effective and economical NO and Hg0 removal technology for coal-fired power plants.