用XPS研究几种沸石的表面组成

A XPS Study of the Surface Composition of Zeolites

本文用XPS研究Y、USY和ZSM-5沸石的表面组成,结果表明:沸石的表面组成(Al/Si)_s与其体相(Al/Si)_b原子比及其骨架Al在晶格中结合强弱有关。Y和载NiY沸石表面层缺Al,USY和ZSM-5沸石表面高度Al富集。在300—600℃加热载NiHY沸石,不伴有Al的移去,结果显示出沸石表面明显缺Al。

In the present paper,we extended these studies of the surface composition of Y,USY,and ZSM-5 zeolites using XPS method.The results show that the surface composition (Al/Si) of Y,USY,and ZSM-5 zeolites depend on both that of the bulk and the framwork aluminum strongly or weakly linked in the lattice.The surface layers of Y and Ni-containing Y zeolites are partially deficient in Al.The surface layers of USY and ZSM-5 zeolites are more rich in that element.Again,heating of the NiHY at 300-600℃without the Al removed,gave the results indicating that the surface deficient in Al may be more obvious.