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Single-Molecule Fluorescence Microscopy Reveals Local Diffusion Coefficients in the Pore Network of an Individual Catalyst Particle
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2017-09-13 , DOI: 10.1021/jacs.7b07139
Frank C Hendriks 1 , Florian Meirer 1 , Alexey V Kubarev 2 , Zoran Ristanović 1 , Maarten B J Roeffaers 2 , Eelco T C Vogt 1 , Pieter C A Bruijnincx 1 , Bert M Weckhuysen 1
Affiliation  

We used single-molecule fluorescence microscopy to study self-diffusion of a feedstock-like probe molecule with nanometer accuracy in the macropores of a micrometer-sized, real-life fluid catalytic cracking (FCC) particle. Movies of single fluorescent molecules allowed their movement through the pore network to be reconstructed. The observed tracks were classified into three different states by machine learning and all found to be distributed homogeneously over the particle. Most probe molecules (88%) were immobile, with the molecule most likely being physisorbed or trapped; the remainder was either mobile (8%), with the molecule moving inside the macropores, or showed hybrid behavior (4%). Mobile tracks had an average diffusion coefficient of D = 8 × 10–14 ± 1 × 10–13 m2 s–1, with the standard deviation thought to be related to the large range of pore sizes found in FCC particles. The developed methodology can be used to evaluate, quantify and map heterogeneities in diffusional properties within complex hierarchically porous materials.

中文翻译:

单分子荧光显微镜揭示单个催化剂颗粒孔网络中的局部扩散系数

我们使用单分子荧光显微镜来研究类似原料的探针分子在微米级、现实生活中的流化床催化裂化 (FCC) 颗粒的大孔中的自扩散,其精度达到纳米级。单个荧光分子的电影允许重建它们通过孔隙网络的运动。通过机器学习,观察到的轨迹被分为三种不同的状态,并且所有状态都均匀地分布在粒子上。大多数探针分子(88%)是固定的,该分子最有可能被物理吸附或捕获;其余部分要么是可移动的(8%),即分子在大孔内移动,要么表现出混合行为(4%)。移动轨道的平均扩散系数为 D = 8 × 10–14 ± 1 × 10–13 m2 s–1,标准偏差被认为与 FCC 颗粒中发现的大范围孔径有关。所开发的方法可用于评估、量化和绘制复杂分级多孔材料内扩散特性的异质性。
更新日期:2017-09-13
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