Understanding the Role of Internal Diffusion Barriers in Pt/Beta Zeolite Catalyzed Isomerization of n‐Heptane. (4th December 2019)

• Record Type: Journal Article
• Authors: Guo, Zhongyuan; Li, Xin; Hu, Shen; Ye, Guanghua; Zhou, Xinggui; Coppens, Marc‐Olivier
• Is Part Of: Angewandte Chemie. Volume 132:Number 4(2020)
• Page Start: 1564
• Page End: 1567
• Publication Date: 2019-12-04
• Subjects: Grenzflächen -- Diffusionsbarrieren -- n-Heptane -- Pt/Beta-Zeolith -- Zeolithkatalyse; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201913660
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Applications of zeolites in catalysis are plagued by strong diffusion resistance, which results from limitations to molecular transport in micropores, across external crystal surfaces, but also across internal interfaces. The first type of diffusion resistance is well understood, the second is receiving increasing attention, while the diffusion barriers at internal interfaces remain largely unclear. We take Pt/Beta catalyzed isomerization of n ‐heptane as the model system to explore the role of internal diffusion barriers in zeolite catalysis. The two as‐synthesized Pt/Beta catalysts have an identical Pt loading, similar Beta particle size and acidity, but different internal structures. A Pt/Beta crystal with no observable internal interfaces can be 180 % higher in activity and 22 % higher in selectivity than its counterpart with numerous internal interfaces. This can only be attributed to the strong transport barriers across internal interfaces, as supported by directly comparing the apparent diffusivities of the two Beta samples. Abstract : Diffusionsbarrieren an Schnittstellen : Beta‐Zeolithe weisen sehr starke interne Diffusionsbarrieren auf, die ihre Aktivität und Selektivität bei der Katalyse der Isomerisierung von n ‐Heptan reduzieren. Der Beta‐Zeolith ohne beobachtbare interne Schnittstellen (siehe Bild) kann 180 % mehr Aktivität und 22 % mehr Selektivität erreichen.