负载Pt的分子筛催化剂研究进展

Advances in Pt-loading zeolite catalysts

阐述了分子筛催化剂负载Pt的研究进展,主要从分子筛负载Pt的制备方法、助剂、Pt前体以及处理条件变化对Pt/分子筛催化剂性能的影响等方面进行了阐述。Pt分散性对分子筛的催化性能具有重大影响,研究表明,通过以下手段可以有效改善Pt的分散性:通过共浸渍的方法引入Ce、Cr、Re、Sn等金属可以有效改善Pt的粒径分布,浸渍液中加入柠檬酸、乙二胺四乙酸作为竞争吸附剂可以有效改善催化剂中Pt的分散性,在焙烧过程中降低升温速度可以有效降低Pt的聚集,低浓度、多次浸渍可以提高Pt的分散性,氧气气氛下焙烧可以提高Pt的分散性,不同的Pt前体负载后Pt的粒径分布存在差异。Pt/分子筛催化剂在不同反应体系中的要求不一样,在具体反应体系中的研究有待进一步加深。

Advances of Pt/zeolite catalysts were reviewed,mainly on the influence of Pt loading,additives,Pt precursors and pretreating conditions on catalysts’ performance. The dispersion of Pt has a significant impact on the catalytic properties of zeolite and can be improved by the following methods. First,introducing Ce,Cr,Re,Sn and other metals by co-impregnation method can effectively improve the particle size distribution of Pt. Adding citric acid or ethylenediamine tetraacetic acid as a competitive adsorbent in the impregnating solution may also improve the Pt dispersion and reducing the heating rate during the calcination process can effectively reduce Pt particle aggregation. In addition,multiple impregnation of Pt with low concentration and calcination under oxygen atmosphere can also improve the Pt dispersion. Catalysts impregnated with different Pt precursors also have different Pt particle size distribution. The requirements of Pt/zeolite catalysts for different reactions are different,which needs further researches for specific reactions.