CO_2活化温度对碳气凝胶结构及氢吸附性能影响

Effects of CO_2 temperature on carbon aerogels porous structures and hydrogen absorption capacity

以间苯二酚(R)和甲醛(F)为前驱体制备出RF碳气凝胶,并利用CO2气体对其进行活化,通过热重分析(TG)、X射线衍射(XRD)、氢吸附等表征手段研究了活化过程中温度对碳气凝胶微结构及氢吸附性能的影响。结果表明:CO2活化可使碳气凝胶比表面积大幅提高,且不会影响其微孔网络结构。随着活化温度的升高,碳气凝胶非晶性变得更加明显,失重率显著增加,微孔体积、比表面积及氢吸附量先增后减,有望通过改变CO2活化温度增加碳气凝胶微孔数量来提高其氢吸附性能。

Carbon aerogels（CA） were prepared from the sol-gel polycondensatin of resorcinol（R） and formaldehyde（F） as raw materials.They were then activated by carbon dioxide.The micro-structure and adsorption properties of hydrogen were analyzed by using thermal gravimetric analysis（TG）,X-ray diffraction（XRD） and adsorption isotherms of hydrogen.The results show that CO2 activation doesn＇t destroy the miropores framework of CA,but substantially increases the specific surface area.With the increase of activation temperature,the amorphous nature of the carbon aerogels becomes more apparent,the weight loss shows a significant increase,and the micropore volume,specific surface area and adsorption capacity of hydrogen increase firstly and then decrease.Thus the hydrogen adsorption capacity can be improved by increasing the micropore structure of the carbon aerogel.