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首页> 外文会议>NATO Advanced Research Workshop on Magnetic Resonance in Colloid and Interface Science, Jun 26-30, 2001, St.Petersburg, Russia >CHARACTERIZATION OF MASS TRANSPORT AND RELATED PHENOMENA IN POROUS CATALYSTS AND SORBENTS BY NMR IMAGING AND DISPLACEMENT NMR SPECTROSCOPY
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CHARACTERIZATION OF MASS TRANSPORT AND RELATED PHENOMENA IN POROUS CATALYSTS AND SORBENTS BY NMR IMAGING AND DISPLACEMENT NMR SPECTROSCOPY

机译：核磁共振成像和位移核磁共振光谱法表征多孔催化剂和吸附剂中的传质及相关现象

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摘要

Applications of NMR imaging in heterogeneous catalysis are rapidly gaining popularity. Due to its nondestructive and noninvasive nature, the technique can be successfully employed to characterize many of the essential stages of catalyst preparation and use, including multiple coupled processes. The dynamics of Pt or Pd redistribution and the type of their ultimate macroscopic distributions in supported Pt/alumina (Pd/alumina) catalysts can be mapped indirectly by ~1H NMR imaging. Flow imaging of liquids and gases provides flow velocity maps and can be used to guide the design of shaped structures such as monolithic catalysts. Displacement NMR spectroscopy yields information on the average flow velocities and hydrodynamic dispersion for gases, liquids and solids flowing through porous media. Imaging of drying of porous pellets and beds comprised of such pellets initially saturated with various liquids, as well as imaging of water vapor adsorption by porous pellets and beds, can provide useful and reliable information on mass transport mechanisms within porous media and interphase mass transfer between the catalyst and the flowing gas. Spatially resolved imaging of gas adsorption on supported catalysts can be employed to study the selectivity of adsorption by active components. Finally, NMR imaging can be applied to monitor the progress of heterogeneous catalytic reactions in real time. The examples of such applications are presented and discussed.
机译：NMR成像在非均相催化中的应用正在迅速普及。由于其非破坏性和非侵入性的特性，该技术可以成功地用于表征催化剂制备和使用的许多基本阶段，包括多重偶联过程。负载的Pt /氧化铝（Pd /氧化铝）催化剂中Pt或Pd重新分布的动力学及其最终宏观分布的类型可以通过〜1H NMR成像间接绘制。液体和气体的流动成像可提供流速图，并可用于指导成形结构（例如整体式催化剂）的设计。位移NMR光谱可得出有关流过多孔介质的气体，液体和固体的平均流速和流体动力分散的信息。多孔颗粒和干燥床的成像（包括最初被各种液体饱和的此类颗粒组成），以及多孔颗粒和床对水蒸气吸附的成像，可以提供有用的和可靠的信息，以了解多孔介质内的传质机理以及相间传质催化剂和流动的气体。可以对载体催化剂上的气体吸附进行空间分辨成像，以研究活性组分吸附的选择性。最后，NMR成像可用于实时监测非均相催化反应的进程。提出并讨论了此类应​​用程序的示例。

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