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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。
Manganese oxide octahedral molecular sieve (OMS-2) was synthesized by KMnO4 and MnSO4. OMS-2 was used as carrier to prepare the supported OMS-2 catalyst with different Ag content by using the former doping method and the impregnation method. The structure and texture of the prepared catalyst were characterized. The effects of different preparation methods and Ag loadings on the catalytic performance of Ag / OMS-2 for CO oxidation were studied. The results show that OMS-2 is a typical one-dimensional cryptomelane tunneling structure. The proper doping of Ag improves the orderliness of OMS-2 support. The catalytic activity of supported Ag / OMS-2 was significantly better than that of OMS-2. The catalytic activity of the former doped method was better than that of the impregnation method. This is related to the Ag particle size in Ag / OMS-2-PI catalyst and the strong interaction between OMS-2 and Ag. The catalytic activity of Ag / OMS-2-PI catalyst was significantly affected by the loading of Ag. The catalytic activity of 3Ag / OMS-2-PI catalyst (Ag = 3.0 wt%) was the highest due to the suitable Ag loading, The interaction between OMS-2 and OMS-2 is relatively good, which can activate OMS-2 lattice oxygen well. Meanwhile, the introduction of Ag makes OMS-2 adsorb the adsorption of CO and the diffusion ability of lattice oxygen significantly. CO oxidation catalytic ability.