【摘要】 以KMnO4和MnSO4为基底采用回流法合成了氧化锰八面体分子筛(OMS-2)。以OMS-2为载体采用前掺杂法和浸渍法制备了不同Ag含量的负载型OMS-2催化剂,对所制催化剂进行了结构和织构表征。并研究了不同制备方法和Ag负载量对Ag/OMS-2催化氧化CO性能的影响。结果表明,OMS-2为典型的cryptomelane一维隧道结构,适量掺杂Ag使OMS-2载体分子筛的有序性得到改善。负载型Ag/OMS-2的催化活性均明显优于OMS-2载体,且前掺杂法催化活性优于浸渍法。这与Ag/OMS-2-PI催化剂中Ag颗粒大小及OMS-2载体与Ag之间存在强相互作用有关。Ag负载量明显影响Ag/OMS-2-PI催化剂的催化活性,3Ag/OMS-2-PI催化剂(Ag=3.0 wt%)催化活性最高,这是由于适当Ag负载量,Ag颗粒较小,与载体OMS-2的相互作用较强,能较好地活化OMS-2晶格氧,同时Ag的引入使OMS-2对CO的吸附性能及晶格氧的扩散能力得到显著增强,提高了催化剂对CO的氧化催化能力。更多还原

【Abstract】 A series of Ag-doped manganese oxide octahedral molecular sieves(OMS-2),used as a sort of catalyst for CO oxidation,were synthesized by pre-incorporation(PI)and conventional wet impregnation(IM)methods on a laboratory scale,and then the investigation was carried out in respect to characterization of the structure of catalysts by X-ray diffraction and N2adsorption/desorption,as well as the influences of different preparation methods and Ag loading amounts on the catalytic activity in CO oxidation. The study found that the catalyst OMS-2,of a typical one-dimensional channel cryptomelane-type structure,when being loaded with adequate amount of Ag could obviously increase the specific surface area,so having much higher catalytic activity in CO oxidation than before,in addition,pre-incorporation(PI)was proven better than wet impregnation(IM). These improvements of Ag/OMS-2 were most likely owing to the character of Ag that was able to significantly enhance the CO adsorption properties and lattice of OMS-2 and oxygen diffusion capacity,thus upgrading the catalytic ability for CO oxidation.更多还原