Assessment of the density of (meso)porous materials from standard volumetric physisorption data
Assessment of the density of (meso)porous materials from standard volumetric physisorption data
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DOI：
10.1016/j.micromeso.2015.10.027
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发表时间：
2016-03
影响因子：
5.2
通讯作者：
C. Weinberger;Simon Vetter;M. Tiemann;T. Wagner
中科院分区：
文献类型：
--
作者：
C. Weinberger;Simon Vetter;M. Tiemann;T. Wagner
（介）孔材料的表征和应用通常需要关于相应样品的密度的信息。例如，根据定义，BET表面积被归一化为样品质量;因此，不同组成的样品之间的任何比较都需要考虑它们各自的密度。关于多孔材料密度的文献数据很少。通常情况下，只有体相密度是可用的，有时不同于多孔样品，特别是无定形系统，如二氧化硅或碳。表观密度，即不包括气体可进入的孔体积的样品的密度，通常通过利用专用比重计的氦气比重测定法来确定。我们演示了如何从标准N2物理吸附测量作为常规测量程序的一部分，获得相同的数据。我们通过使用无孔参考样品（玻璃棒）的参考测量来评价该方法，以确认该方法的有效性。然后，我们提出了几个介孔二氧化硅材料（MCM-41，MCM-48，SBA-15，KIT-6），介孔碳（CMK-3，-5，-8，-9），和各种介孔金属氧化物纳米铸造获得的表观密度测量结果。
Characterization and application of (meso)porous materials often require information about the density of the respective samples. For example, the BET surface area is, by definition, normalized to the sample mass; hence, any comparison between samples of different composition needs to take into account their respective densities. Literature data on the densities of porous materials are scarce. Frequently, only bulk-phase densities are available which sometimes differ from those of porous samples, especially for amorphous systems, such as silica or carbon. The apparent density,i.e.the density of the sample excluding the gas-accessible pore volume, is typically determined by helium gas pycnometry utilizing specialized pycnometers. We demonstrate how to obtain the same data from standard N2physisorption measurements as part of the regular measurement routine. We evaluate the method by reference measurements utilizing a non-porous reference sample (glass rod) to confirm the validity of the method. Then we present results on apparent density measurements of several mesoporous silica materials (MCM-41, MCM-48, SBA-15, KIT-6), mesoporous carbon (CMK-3, -5, -8, -9), and a variety of mesoporous metal oxides obtained by nanocasting.