Improvement of mesoporosity of carbon cryogels by ultrasonic irradiation
Improvement of mesoporosity of carbon cryogels by ultrasonic irradiation
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DOI：
10.1016/j.carbon.2004.10.015
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发表时间：
2005
期刊：
影响因子：
10.9
通讯作者：
N. Tonanon;A. Siyasukh;W. Tanthapanichakoon;H. Nishihara;S. Mukai;H. Tamon
中科院分区：
文献类型：
--
作者：
N. Tonanon;A. Siyasukh;W. Tanthapanichakoon;H. Nishihara;S. Mukai;H. Tamon
介孔碳凝胶通常通过热解间苯二酚-甲醛（RF）凝胶来获得，所述RF凝胶通过间苯二酚与甲醛在微碱性水溶液中的溶胶-凝胶缩聚然后干燥来合成。然而，即使使用超临界干燥或冷冻干燥，在高催化剂浓度或RF溶液的高pH的条件下也不能制备介孔碳凝胶。本文采用超声波辐照射频溶液的方法来改善炭冻凝胶的介孔性。结果表明，超声辐照能显著缩短RF溶液的凝胶化时间，提高催化剂浓度（C/W）时制备的炭冻凝胶的介孔率。在C/W= 80 mol/m3的条件下制备的炭冻凝胶没有中孔，而在相同的催化剂条件下超声辐照制备的炭声凝胶具有明显的中孔尺寸分布。利用超声波制备RF凝胶是一种有趣的方法，可以改善在高C/W或pH下制备的碳凝胶的介孔性。
Mesoporous carbon gels are usually obtained by pyrolyzing resorcinol–formaldehyde (RF) gels, which are synthesized via the sol–gel polycondensation of resorcinol with formaldehyde in a slightly basic aqueous solution followed by drying. However, mesoporous carbon gels cannot be prepared under the conditions of high catalyst concentration or high pH of RF solution even by using supercritical drying or freeze drying. In this work, mesoporosity of carbon cryogels is improved by ultrasonic irradiation to RF solution. It is found that the gelation time of RF solution becomes greatly short by ultrasonic irradiation and that ultrasonic can improve mesoporosity of carbon cryogels prepared at high catalyst concentration (C/W). Although the carbon cryogels prepared from C/W=80mol/m3have no mesopores, the carbon sonogels prepared by ultrasonic irradiation under the same catalyst condition have sharp mesopore size distribution. The utilization of ultrasonic in the preparation of RF gel is an interesting way in improving mesoporosity of carbon gels prepared at high C/W or pH.