School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China.
J Phys Chem Lett. 2023 Apr 13;14(14):3567-3573. doi: 10.1021/acs.jpclett.3c00698. Epub 2023 Apr 5.
The diffusion processes in zeolites are important for heterogeneous catalysis. Herein, we show that unique zeolites with "continuum intersecting channels" (e.g., BEC, POS, and SOV), in which two intersections are proximal, are greatly significant to the diffusion process with spontaneous switching of the diffusion pathway under varied loading. At low loading, the synergy of strong adsorption sites and molecular reorientation in intersections contribute to almost exclusive molecular diffusion in smaller channels. With an increase in molecular loading, the adsorbates are transported preferentially in larger channels mainly due to the lower diffusion barrier inside continuum intersection channels. This work demonstrates the ability to adjust the prior diffusion pathway by controlling the molecular loading, which may be beneficial for the separation of the product and byproduct in heterogeneous catalysis.
沸石中的扩散过程对于多相催化很重要。在此，我们表明，具有“连续相交通道”（例如 BEC、POS 和 SOV）的独特沸石对于扩散过程非常重要，在不同负载下，扩散途径会自发切换。在低负载下，强吸附位和分子在交点处的重排协同作用导致较小通道中几乎只发生分子扩散。随着分子负载的增加，吸附物主要由于连续相交通道内部的扩散势垒较低而优先在较大通道中传输。这项工作证明了通过控制分子负载来调整优先扩散途径的能力，这对于多相催化中产物和副产物的分离可能是有益的。
