Effects of CO₂ temperature on carbon aerogels porous structures and hydrogen absorption capacity

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 capaci