Mn-Mg-Al-O催化剂上NOx的氧化 储存性能

采用共沉淀法制备系列Mn-Mg-Al-O水滑石前驱体，经500℃焙烧制成复合氧化物Mn-Mg-Al-O催化剂，并用XRD方法进行了表征。恒温储存实验研究了催化剂氧化NO和储存NO_x的性能，NO_x-TPD考察了储存的NO_x脱附情况。结果表明，Mn在前驱体中高度分散；焙烧后，Mg₂MnO₄是主要的活性组分，Mn能够催化NO的氧化反应，且有一定的NO_x储存能力，Mg是主要的储存组分，将NO_x以硝酸盐的形式储存起来；硝酸盐在氮气气氛中300℃～600℃下分解，释放出NO_x。不同含量的SO₂均使催化剂NO_x储存能力降低。

Oxidation-storage of NO_x over Mn-Mg-Al-O catalyst

A series of Mn-Mg-Al-O hydrotalcite precursors with M(II)/Al(III) molar ratio of 3 were prepared by co-precipitation method; corresponding mixed oxides were obtained after calcinations at 500℃. The Mn-Mg-Al-O catalysts were characterized by XRD. Their performance for NO_x oxidation storage was investigated by adsorption measurements at constant temperature with or without SO₂ and the desorption of stored NO_x was also investigated by TPD under N₂. The results showed that Mn was well dispersed in the precursors. Mg₂MnO₄ was the major active component after calcinations. Mn was catalytically active for the oxidation of NO and exhibited certain NO_x storage capacity. Mg was the major component for NO_x storage; NO_x were stored with the formation of the nitrate that can be decomposed to NOx at 300℃~600℃ under N₂. The NO_x storage capacity was decreased by the presence of SO₂.