Enhanced Stability and Selectivity in Pt@MFI Catalysts for n-Butane Dehydrogenation: The Crucial Role of Sn Promoter

作者：Nengfeng Gong, Gaolei Qin, Pengfei Li, Xiangjie Zhang, Yan Chen, Yong Yang, Peng He · 发表于：Catalysts · 年份：2024 · DOI：10.3390/catal14110760 · 被引用次数：5 · 研究领域：Catalytic Processes in Materials Science、Catalysis and Oxidation Reactions、Zeolite Catalysis and Synthesis

The dehydrogenation of n-butane to butenes is a crucial process for producing valuable petrochemical intermediates. This study explores the role of oxyphilic metal promoters (Sn, Zn, and Ga) in enhancing the performance and stability of Pt@MFI catalysts for n-butane dehydrogenation. The presence of Sn in the catalyst inhibits the agglomeration of Pt clusters, maintaining their subnanometric particle size. PtSn@MFI exhibits superior stability and selectivity for butenes while suppressing cracking reactions, with selectivity for C1–C3 products as low as 2.1% at 550 °C compared to over 30.5% for Pt@MFI. Using a combination of high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Raman spectroscopy, we examined the structural and electronic properties of the catalysts. Our findings reveal that Zn tends to consume hydroxyl groups and substitute framework sites, and Ga induces more defective sites in the zeolite structure. In contrast, the interaction between SnOx and the zeolite framework does not depend on reactions with hydroxyl groups. The incorporation of Sn significantly prevents Pt particle agglomeration, maintaining smaller Pt particle sizes and reducing coke formation compared to Zn and Ga promoters. Theoretical calculations showed that Sn increases the positive charge on Pt clusters, enhancing their interaction with the zeolite framework and reducing sintering, albeit with a slight increa...