稀土氧化物上SO_2和NO的催化还原(Ⅲ)──用CO作还原剂的同步脱硫和脱氮

Catalytic Reduction of SO_2 and NO by CO on Rare Earth Oxides(Ⅲ)──Simultaneous Reduction by Using CO as Reducing Agent

考察了稀土系列氧化物作为CO同步还原SO2和NO催化剂的活性．结果表明，氧化钐和氧化钕表现了最高的活性，在475℃，SO2 和NO的转化率同时超过95％．实验发现稀土氧硫化物是活性相．通常脱硫活性高的样品同样具有高的脱氮活性，但CeO2 表现了不同的行为，其脱硫活性虽低，但脱氮活性却较高．文中还对同步反应的机理作了探讨，发现COS不仅是还原SO2 的中间物，同时也是还原NO的中间物．结合活性相和反应机理对不同稀土氧化物的活性差异作了讨论．

Abstract Rare earth oxysulfides obtained from the activation of rare earth oxides were effective catalysts for the simultaneous reduction of SO2 and NO by CO to elemental S. The most active catalysts were Sm2O2S and Nd2O2S, over which a conversion of >95% for both SO2 and NO was obtained at 475 . Exceptional behavior was observed over CeO2 , which showed a low activity for desulfurization, but a high activity for denitrification. The seperating experimental results showed that GOS was an intermediate not only for the reduction of SO2 by CO but also for the reduction of NO by CO. Thus, a COS intermediate mechanism was proposed to describe the simultaneous reaction. Based on the mechanism, the difference a-mong the activities of the rare earth oxides was discussed.