Pt在SAPO-11分子筛上的分散性研究

Study on dispersity of platinum on SAPO-11 zeolite

采用H2-TPR、NH3-TPD、H2脉冲化学吸附和H2-O2化学滴定等方法对Pt/SAPO-11催化剂上金属分散进行了表征,并与该催化剂制备因子及其正构烷烃骨架异构化反应性能进行关联。实验表明,以与NH3配位的阳离子形式制备的催化剂,Pt的分散效果最好;用低浓度浸渍液、多次浸渍的方式制备的催化剂,Pt的分散度高;M n2+、Sm3+、Zn2+等作助剂和Pd-Pt复合浸渍可提高Pt的分散度。调整分子筛的酸量使之与金属含量达到平衡时,催化剂活性和选择性最佳。

H2-TPR, NH3-TPD, pulse adsorption of hydrogen and H2-O2 titration were employed to analyze and correlate the platinum dispersity on Pt/SAPO-11 catalyst with preparation of the catalyst and performance of skeletal isomerization of n -C12 alkane. It was found that the precursor of metal amine complex and maceration with low metal concentration and multiple maceration are favored to improve the dispersity of platinum on catalyst. The introduction of additives of Mn^2＋ , Sm^3＋ and Zn^2＋ and binary metal maceration are feasible to promote the dispersity of metal. In addition, matching of the acidity and metal content is optimum to catalytic performance of Pt/SAPO-11 catalyst.