纳米ZSM-5分子筛的合成及其催化转化甲醇性能

Synthesis of nanocrystal ZSM-5 molecular sieves and their catalytic performance for methanol conversion

通过在常规的分子筛合成水热体系中加入适量NaCl,合成了纳米ZSM-5分子筛,采用XRD、SEM、N2吸附和NH3-TPD等方法对其结构进行表征,并评价在甲醇制丙烯反应中的催化性能。结果表明,合成的ZSM-5分子筛分散性良好,粒度分布均一,晶粒大小约为100 nm,与微米级ZSM-5分子筛相比,纳米ZSM-5分子筛催化剂具有更大的比表面积(402.0 m2·g-1)和孔容(0.41 cm3·g-1),在甲醇制丙烯催化反应中表现出更好的催化性能,丙烯选择性远高于微米级ZSM-5分子筛,且表现出很高的活性和稳定性,运行140 h,甲醇转化率仍大于90%。

Nanocrystal ZSM-5 molecular sieves were synthesized by adding proper amount of sodium chloride into conventional hydrothermal system and characterized by means of XRD, SEM, nitrogen adsorption （BET） and NHa-TPD. Their catalytic performances for methanol-to-propylene reaction were evaluated. The results showed that compared with microcrystal ZSM-5 molecular sieves, nanocrystal ZSM-5 molecular sieves with crystal size about 100 nm possessed higher surface area （402.0 m2·g^-1） ,larger pore volume （0.41 cm3·g^-1）, good dispersibility and uniform particle size distribution; nanocrystal ZSM-5 catalyst exhibited much higher activity and selectivity to propylene in methanol-to-propylene process, and the methanol conversion could maintain above 90% even after running for 140 h.