Wang Chao, Brenig Andreas, Xu Jun, Deng Feng, Paunović Vladimir, van Bokhoven Jeroen A
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland.
National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
J Am Chem Soc. 2024 Dec 18;146(50):34279-34284. doi: 10.1021/jacs.4c13212. Epub 2024 Dec 10.
Understanding the mechanism of steam-induced dealumination of zeolite catalysts is of high relevance for tuning their performance and stability in multiple industrial processes. A combination of Al and H-H double-quantum single-quantum magic angle spinning nuclear magnetic resonance and diffuse-reflectance ultraviolet-visible spectroscopies identified a preferential dealumination of tetrahedral aluminum sites in H-ZSM-5 zeolites. Framework aluminum atoms facing channels display reactivity toward steam higher than that of those in their intersections. Dealumination randomly occurs on isolated and proximate sites. However, the concentration of the latter sites decays more prominently. These findings contribute to a better understanding of the stability of zeolite catalysts in the presence of steam.
了解蒸汽诱导的沸石催化剂脱铝机理对于在多个工业过程中调节其性能和稳定性具有高度相关性。结合铝和氢-氢双量子单量子魔角旋转核磁共振以及漫反射紫外-可见光谱，确定了H-ZSM-5沸石中四面体铝位点的优先脱铝。面向通道的骨架铝原子对蒸汽的反应性高于其交叉处的铝原子。脱铝随机发生在孤立位点和相邻位点。然而，后者位点的浓度衰减更为显著。这些发现有助于更好地理解沸石催化剂在蒸汽存在下的稳定性。
