碱性在Pt／L分子筛催化剂中的作用

THE FUNCT1ON OF BASICITYONPt/L ZEOLITE REFORMING CATALYST

用ＣＯ＿２－ＴＰＤ，ＴＥＭ，ＰＡＳｃＡ等表征手段，考察了Ｐｔ／Ｌ分子筛催化剂上碱性对金属分散度、活性中心的影响及其内在联系，首次对Ｌ分子筛上碱性位的分布进行了讨论，结果发现，碱性的存在可以改善金属铂的分散度；高分散的金属铂是位于分子筛中电子给予体上，即碱性位上；载体与金属之间的相互作用使得金属铂上富集电子，烷烃氢解受到抑制，从而一步实现了双功能催化剂上进行二组分，三组分，乃至四组分金属调变以改善催化剂脱氢环化性能的目的。

The effect of basicity on the performance of Pt/ML(M=Li,Na,K,Rb)zeo-lite catalysts was studied using the aromatization of nC_6 as the test reaction。Consistent re-sults in catalvst characterization were obtained.Four dinerent Kinds of surface site of differ-ent basic strength and metal-support electronic interaction were identified by CO_-TPDand PASCA measurements res pectively. These four basic sites were assigned to the corre-sponding cation locations of C,D,B and A in the L zeolite framworks.A significantly in-creasing trend of LiL<NaL<KL<RbL was observed for the selectivitv of the catalysts,inparalled with the increasing trend of metal-support interaction in these Pt/ML catalysts。