N掺杂Mo/HZSM-5催化剂制备及对甲烷无氧芳构化催化性能影响

Preparation of N-doped Mo/HZSM-5 catalyst and its effect on performance of non-oxidative methane aromatization reaction

  • 摘要: 采用三聚氰胺作为N源,N掺杂改性HZSM-5沸石分子筛后负载Mo活性金属组分,制备了一种用于甲烷无氧芳构化反应(MDA)的催化剂。采用XPS、N2吸附-脱附、XRD、H2-TPR、TEM和NH3-TPD对催化剂性质和Mo金属组分状态进行了分析表征,并考察了催化剂的甲烷无氧芳构化反应催化性能。结果表明,HZSM-5经过N掺杂改性后,会在分子筛表面生成一层含氮基团,有序调控了分子筛的酸性位点;同时会诱导Mo金属组分在催化剂表面更好的锚定落位。此方法制备的Mo/HZSM-5-CN催化剂能有效提高MDA反应的甲烷转化率和芳烃选择性,减缓了积炭的生成,展现出更优良的催化性能。

     

    Abstract: Catalysts for methane dehydroaromatization (MDA) were prepared using melamine as nitrogen source, doped with modified HZSM-5 zeolites and loaded with active metal component Mo. Using XPS, N2-isothermal adsorption and desorption, XRD, H2-TPR, TEM and NH3-TPD, properties of the catalyst and state of active metal components were analyzed. Its catalytic performance for MDA reaction was investigated. The results showed that HZSM-5 after modified with melamine not only formed a layer of carbon and nitrogen groups on surface of the zeolites, but also controlled the medium and strong acid sites of the zeolites in orderly. At the same time it induced better anchor of Mo metal components on surface of the catalyst. The Mo/HZSM-5-CN catalyst prepared by this method could effectively increase methane conversion rate and aromatic selectivity of the MDA reaction, slow down generation of carbon deposits, and exhibit better catalytic performance.

     

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