發(fā)布時(shí)間：2018-08-03 13:24

【摘要】：利用微波輔助水熱合成法直接制備了納米HZSM-5晶體。采用XRD、FT-IR、SEM、BET和NH_3-TPD等手段對(duì)合成樣品進(jìn)行了分析表征,研究了晶化溫度和時(shí)間對(duì)合成產(chǎn)物晶體性質(zhì)的影響。結(jié)果表明,晶化溫度和時(shí)間對(duì)微波輔助水熱直接合成產(chǎn)物微觀形貌、晶粒尺寸和分散度影響明顯。較低的晶化溫度和較短的晶化時(shí)間均難以形成形貌規(guī)則的HZSM-5晶體。隨著晶化溫度的升高,合成樣品逐漸變?yōu)榍蛐尉Я�、晶粒尺寸逐漸增大、分散度逐漸提高,繼續(xù)提高晶化溫度達(dá)180℃時(shí),晶粒長大使比表面積稍有降低;隨著晶化時(shí)間的延長,樣品的微孔和介孔增多,比表面積和孔容逐漸增大,繼續(xù)延長晶化時(shí)間,晶體內(nèi)微孔可能的收縮和晶粒的長大使得樣品孔容和比表面積減小。160℃和1.5 h條件下制備的HZSM-5分子篩晶體形貌呈球形,晶粒尺寸約為60 nm,分散程度較好;其比表面積、孔容和平均孔徑分別為398.45 m~2·g~(-1)、0.63 cm~3·g~(-1)和6.27 nm;晶體表面具有弱酸特征。
[Abstract]:Nanocrystalline HZSM-5 crystals were prepared by microwave-assisted hydrothermal synthesis. The synthetic samples were characterized by XRDD-FT-IRT-SEMT-BET and NH_3-TPD, and the effects of crystallization temperature and time on the crystal properties of the synthesized products were studied. The results show that the effect of crystallization temperature and time on the microstructure, grain size and dispersion of microwave-assisted hydrothermal direct synthesis products is obvious. It is difficult to form HZSM-5 crystal with regular morphology at lower crystallization temperature and shorter crystallization time. With the increase of crystallization temperature, the synthesized samples gradually become spherical grains, the grain size increases gradually, and the dispersity increases gradually. When the crystallization temperature continues to increase to 180 鈩，

本文編號(hào)：2161878