Propane Dehydrogenation over Pt Clusters Localized at the Sn Single-Site in Zeolite Framework

Abstract

Catalytic dehydrogenation of propane over a Pt-based catalyst to propylene has received considerable interests in recent years because this route is able to provide an economical and efficient way to fill the gap between supply and demand in propylene market. The low dispersion of a Pt particle at the support surface and sintering of Pt nanoparticles under the harsh reaction condition are the main challenges in the practical application of this catalyst. Herein, highly efficient Pt/Sn-Beta catalysts are developed for propane dehydrogenation, which exhibits high activity, selectivity, and stability in this reaction. Full characterizations with XRD, STEM, XPS, CO-IR, H2-TPR, and Py-IR techniques on these catalysts reveal that the Pt clusters are localized at the Sn single-site in the zeolitic framework, which allows the generated Pt clusters to be homogeneously dispersed at the surface zeolite. The high performance of Pt/Sn-Beta catalysts under a high reaction temperature is mainly due to a strong interaction between the Pt cluster and Sn-zeolite. An initial propane conversion of 50%, high propylene selectivity of above 99%, low deactivation rate of 0.006 h–1, high TOF of 114 s–1, and good regenerability have been achieved in the Pt-Sn2.00/Sn-Beta catalyst for propane dehydrogenation at 570 °C.

Enhanced stability of Pt/Al2O3 modified by Zn promoter for catalytic dehydrogenation of ethane

“…and 1450 cm −1 were selected for representing pyridine interacted with Br φnsted and Lewis acid site, respectively [57] . In agreement with the previous studies [58][59][60] , only Lewis acid sites can be detectable in both Pt/Al 2 O 3 and PtZn 2 /Al 2 O 3 samples, and the quantified Lewis acidity values are 102.1 and 77.7 μmol/g, respectively. The decreasing acid sites on PtZn 2 /Al 2 O 3 indicate that coke deposition can be further suppressed via neutralizing the acidity by Zn.…”

Novel Strategy for the Synthesis of Ultra‐Stable Single‐Site Mo‐ZSM‐5 Zeolite Nanocrystals

“…Fore xample,t he dehydrogenation of propane to propylene employs alumina-supported catalysts, [4] however, state of the art synthetic procedures have demonstrated several new strategies to improve the activity and stability of zeolitesupported catalysts such as the encapsulation of metal atoms and clusters during the zeolite synthesis, [5] stabilisation of the metal phase in the zeolite channels by alkali metals, [2] and the use of framework-metal sites to stabilise extra-framework active sites. [6] Similar to the dehydrogenation of propane, there are no commercial zeolite-based catalysts for the nonoxidative conversion of methane to hydrogen and industrially important chemicals (olefins,a romatics). This process is ad irect route to decarbonize methane to petrochemicals while co-producing ac lean energy vector-hydrogen.…”

Emphasis on the Properties of Metal‐Containing Zeolites Operating Outside the Comfort Zone of Current Heterogeneous Catalytic Reactions

“…Xu et al . reported their optimized catalyst (0.5 wt % Pt, 1.0 wt % Sn) demonstrated 50 % conversion at the beginning of the reaction, decreasing to 45 % over 48 h at 570 °C.…”