以Y分子筛和HZSM-5分子筛为前驱体,以纯氨为氮源,在800℃焙烧制备了氮化微孔分子筛。采用元素分析、氮气吸附-脱附、X射线衍射(XRD)、原位漫反射红外光谱等技术对材料的结构与酸碱性能进行了研究。结果表明,NaY分子筛是可获得高比表面积和完整结构掺氮分子筛理想的前驱体。原位漫反射红外光谱证实了氮原子主要以-NH2-或-NH-形式进入各分子筛骨架。原位探针分子吸附漫反射红外光谱实验表明两种分子筛均含B酸位与L酸位,经高温氨处理掺氮后B酸位显著减少、L酸位变化不明显,碱性变强。
Nitrogen-incorporated microporous zeolites were prepared by calcining Y zeolite and HZSM-5 zeolite precursors at 800 ℃ and with pure ammonia as nitrogen source.The structure and acid-base properties of the samples were investigated by means of elemental analysis, nitrogen adsorption-desorption, XRD, and DRIFTS etc..Results indicated NaY was a good pre- cursor which could obtain high BET surface area and intact structure of nitrogen-incorporated zeolite. DRIFTS experiments confirmed that N atoms have been introduced into the framework of each zeolite by nitridation to form -NH2- or -NH- species.Moreover,Brcnsted and Lewis acid sites coexisted in two zeolites.When nitridation at high temperature, Brcnsted acid sites decreased sharply while Lewis acid sites changed slightly and the alkalinity became stronger.