Tailoring the textural properties of activated carbon xerogels by chemical activation with KOH
Tailoring the textural properties of activated carbon xerogels by chemical activation with KOH
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DOI：
10.1016/j.micromeso.2008.02.023
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发表时间：
2008-11
影响因子：
5.2
通讯作者：
L. Zubizarreta;A. Arenillas;J. Pirard;J. J. Pis-J.;N. Job
中科院分区：
文献类型：
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作者：
L. Zubizarreta;A. Arenillas;J. Pirard;J. J. Pis-J.;N. Job
合成了不同间苯二酚/碳酸钠摩尔比的间苯二酚-甲醛干凝胶，分别在干燥后或干燥热解后用氢氧化钾进行了化学活化。研究发现，有机(即干燥)和碳(即热解)干凝胶在受到化学活化时的行为不同。在碳干凝胶的情况下，微孔率的增加不会对合成步骤中形成的中孔/大孔进行任何显著的修改，从而导致具有更大微孔体积的微介孔或微大孔材料。此外，微孔率的控制是可能的，因为它的发展取决于KOH的使用量。然而，当有机干凝胶被活化时，得到的主要是比表面积高达2000m2g−1的微孔材料，几乎没有在凝胶合成过程中形成的中孔/大孔。因此，不同的合成条件和氢氧化钾的化学活化相结合，可以在微孔和中孔/大孔水平上定制碳干凝胶的织构特性。
Resorcinol–formaldehyde xerogels synthesised with different resorcinol/sodium carbonate molar ratios were chemically activated either after drying or after drying and pyrolysis, using potassium hydroxide. It was found that organic (i.e. dried) and carbon (i.e. pyrolysed) xerogels behave differently when subjected to chemical activation. In the case of carbon xerogels, the increase in the microporosity takes place without any significant modification to the meso/macroporosity formed during the synthesis step, leading to micro–mesoporous or micro–macroporous materials with a larger micropore volume. Furthermore, control of the microporosity is possible because its development depends on the amount of KOH used. However, when organic xerogels are activated, mainly microporous materials with BET specific surface areas of up to 2000m2g−1are obtained, there hardly remaining any of the meso/macroporosity formed during the gel synthesis. Thus, the combination of different synthesis conditions and chemical activation with potassium hydroxide allows the textural properties of carbon xerogels to be tailored at both micropore and meso/macropore levels.