高温氮化对Hβ分子筛物化性能的影响研究

Effects of High Temperature Nitriding on the Physicochemical Properties of Hβ Zeolite

通过高温氮化法对Hβ分子筛进行改性,制备出含氮的Hβ分子筛。通过X射线衍射(XRD)、N_(2)物理吸附、红外光谱(FT-IR)、X射线光电子能谱(XPS)、NH3程序升温脱附(NH3-TPD)和CO_(2)程序升温脱附(CO_(2)-TPD)等方法对氮化后Hβ分子筛的结构和酸碱性质进行表征分析。结果表明,高温氮化后Hβ分子筛的晶体结构未发生明显变化,但随着氮化温度的升高,Hβ分子筛的比表面积和孔体积均显著降低,且酸量变少、酸强度变弱;经800℃氮化处理后,Hβ分子筛出现-NH2-和-NH-基团,产生了新的碱性位。

A series of nitrogen-containing β zeolites were prepared by treating Hβzeolites with NH3 at high-temperature.The structural properties,acidity and basicity of the nitridedβzeolites were characterized by X-ray diffraction(XRD),N_(2) adsorption,Fourier infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),NH3 temperature programmed desorption(NH3-TPD)and CO_(2) temperature programmed desorption(CO_(2)-TPD).It was found that the high-temperature nitriding did not affect the crystal structure of theβzeolite obviously,but the specific surface area and pore volume of theβzeolite decreased significantly with the increase of the nitriding temperature.The amount of acid sites reduced,and the acidity became weaker.The new basic sites were found on theβzeolite,which the-NH2-and-NH-groups were generated after nitridation at 800℃.