Silanol-Stabilized Atomically Dispersed Pt δ+ -O x -Sn Active Sites in Protozeolite for Propane Dehydrogenation

作者：Jialiang Li, Qiang Zhang, Guangyuan He, Tianjun Zhang, Lin Li, Junyan Li, Dapeng Hao, Wei Zhang, Osamu Terasaki, Donghai Mei, Jihong Yu · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.4c05727 · 被引用次数：93 · 研究领域：Catalysis and Oxidation Reactions、Catalytic Processes in Materials Science、Zeolite Catalysis and Synthesis

Crystalline zeolites have been proven to be excellent supports for confining subnanometric metal catalysts to boost the propane dehydrogenation (PDH) reaction. However, the introduced metallic species may suffer from severe sintering and limited stability during the catalytic process, especially when utilizing an industrial impregnation method for metal incorporation. In this study, we developed a new type of support based on amorphous protozeolite (PZ), taking advantage of its adjustable silanol chemistry and zeolitic microporous characteristic for stabilizing atomically dispersed PtSn catalyst via a simple, cost-effective coimpregnation process. The combination of X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy under CO atmosphere, and density functional theory calculations confirmed the formation of highly dispersed active Pt δ+ -O x -Sn species in PtSn/PZ. The PtSn/PZ catalyst exhibited a high propane conversion of 45.4% and a high propylene selectivity of 99% (WHSV= 3.6 h –1, 550 °C), with a high apparent rate coefficient of 565 mol C 3 H 6 ·g Pt –1 ·h –1 ·bar –1 at a high WHSV of 108 h –1, presenting a top-level performance among the state-of-the-art Pt-based catalysts prepared by in situ synthesis and impregnation methods. The silanol density determined the chemical state of PtSn species, showing a change from atomically dispersed Pt δ+ -O x -Sn sites to PtSn alloy with decreasing sila...