Preparation of carbon cryogels from wattle tannin and furfural
Preparation of carbon cryogels from wattle tannin and furfural
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DOI：
10.1016/j.micromeso.2006.09.007
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发表时间：
2007-01-05
影响因子：
5.2
通讯作者：
Lothongkum, A. W.
中科院分区：
文献类型：
--
作者：
Kraiwattanawong, K.;Mukai, S. R.;Lothongkum, A. W.
以荆树单宁和糠醛为原料，在NaOH、Na 2CO 3和NaHCO 3三种碱催化剂作用下，通过溶胶-凝胶缩聚反应合成了荆树单宁-糠醛（TFu）水凝胶。通过冷冻干燥的水凝胶和TFU碳的冷冻凝胶的冷冻凝胶，通过热解的冷冻凝胶在惰性气氛中得到的TFU碳冷冻凝胶。采用N2吸附法和扫描电子显微镜（SEM）对TFu和炭冻凝胶进行了表征。催化剂对炭晶凝胶孔性能的影响表现在两个方面：（1）NaOH促进炭晶凝胶的中孔体积和比表面积的增加;（2）Na_2CO_3和NaHCO_3降低炭晶凝胶的中孔体积和比表面积。以NaOH为催化剂制备的TFu和炭冻凝胶具有较大的中孔体积。尽管TFu冷冻凝胶具有比间苯二酚-甲醛（RF）冷冻凝胶小的表面积和中孔体积，但碳冷冻凝胶具有不同于RF碳凝胶的独特多孔性质。结果表明：（1）热解后中孔体积变化不大;（2）热解后孔半径增大;（3）热解过程中微孔不明显。(C)2006爱思唯尔公司All rights reserved.
Wattle tannin-furfural (TFu) hydrogels were synthesized by the sol-gel polycondensation of wattle tannin with furfural by using three types of base catalysts (NaOH, Na2CO3 and NaHCO3). TFu cryogels were prepared by freeze drying of the hydrogels and TFu carbon cryogels were obtained by pyrolysis of the cryogels in an inert atmosphere. The TFu and carbon cryogels were characterized by N-2 adsorption and scanning electron microscope (SEM). The effect of catalysts on porous properties of carbon cryogels resulted in different ways: (1) NaOH enhances increasing mesopore volumes and surface area of carbon cryogels and (2) Na2CO3 and NaHCO3 cause decreasing those of carbon cryogels. The TFu and carbon cryogels prepared by using NaOH as a catalyst possessed large mesopore volumes comparing with micropore volumes. Even though the TFu cryogels have surface area and mesopore volumes smaller than the resorcinol-formaldehyde (RF) cryogels, the carbon cryogels have unique porous properties differed from the RF carbon gels. The properties are summarized as follows: (1) the mesopore volume changes insignificantly after pyrolysis, (2) the pore radius is increased after pyrolysis and (3) micropores are not greatly developed during pyrolysis. (C) 2006 Elsevier Inc. All rights reserved.