High-Resolution N2 Adsorption Isotherms at 77.4 K: Critical Effect of the He Used During Calibration
High-Resolution N2 Adsorption Isotherms at 77.4 K: Critical Effect of the He Used During Calibration
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77.4 K 处的高分辨率 N2 吸附等温线：校准过程中使用的 He 的关键影响
DOI：
10.1021/jp405719a
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
F. Rodríguez
中科院分区：
文献类型：
--
作者：
J. Silvestre;A. Silvestre;P. Llewellyn;F. Rodríguez
准确表征多孔固体中的微孔结构对于能量和气体储存、纳米约束反应等应用具有至关重要的意义。在不同的精确结构表征技术中，在低温（例如77.4 K的N2和87.3 K的Ar）下对探针分子进行高精度气体吸附测量是最广泛使用的，使用探针气体对样品支架进行适当校准后，不会经历物理吸附过程。虽然传统上认为氦在低温下不被吸附在多孔固体中，但在这里我们表明，即使在77.4 K（高于其沸点4 K）时，在校准步骤中使用He可能会导致错误的解释，因为存在狭窄的微孔/收缩。
Accurate characterization of the microporous structure in porous solids is of paramount importance for several applications such as energy and gas storage, nanoconfinement reactions, and so on. Among the different techniques for precise textural characterization, high-precision gas adsorption measurement of probe molecules at cryogenic temperatures (e.g., N2 at 77.4 K and Ar at 87.3 K) is the most widely used, after appropriate calibration of the sample holder with a probe gas, which does not experience physisorption processes. Although traditionally helium has been considered not to be adsorbed in porous solids at cryogenic temperatures, here we show that even at 77.4 K (high above its boiling temperature, 4 K) the use of He in the calibration step can give rise to erroneous interpretations when narrow micropores/constrictions are present.