丙烷/异丁烷脱氢Pt系催化剂的研究进展 Ⅲ.Pt的存在形态、颗粒大小与脱氢性能

Pt-based catalysts for propane/isobutane dehydrogenation Ⅲ. Existing state and particle size of Pt

在脱氢反应过程中,Pt催化剂中Pt以金属形式存在并发挥脱氢作用。引入Sn后,部分Pt会与Sn形成合金,Pt-Sn合金的脱氢活性低。Pt的分散度高,颗粒小,其脱氢活性高;但是,在没有Sn的情况下,生成的烯烃不易脱附,导致选择性不高。Pt的分散度与Pt的前驱体、载体、助剂、制备方法和条件等因素有关。

Metallic Pt species existing on Pt - based catalysts played an important role in alkane dehydrogenation. After the introduction of Sn, Pt - Sn alloy could be formed and it possessed low dehy- drogenation activity. Pt- based catalysts with higher dispersion and smaller particles exhibited higher de- hydrogenation activity. However, the selectivity of olefins was not high due to their stro the catalyst surface without Sn. The ng adsorption on dispersion of Pt was influenced by many factors including the precur- sors of Pt, supports, promoters, preparation methods and conditions, etc.