High surface carbon aerogels with hierarchical and tunable pore structure were prepared using ionic liquid as carbon precursor via a simple salt templating method. The as-prepared carbon aerogels were characterized by nitrogen sorption measurement and scanning electron microscopy. Through instant visual observation experiments, it was found that salt eutectics not only serve as solvents, porogens, and templates, but also play an important role of foaming agents in the preparation of carbon aerogels. When the pyrolyzing temperature rises from 800 to 1000°C, the higher temperature deepens the carbonization reaction further to form a nanoporous interconnected fractal structure and increase the contribution of super-micropores and small mesopores and improve the specific surface area and pore volume, while having few effects on the macropores. As the mass ratio of ionic liquid to salt eutectics drops from 55% to 15%, that is, the content of salt eutectics increases, the salt eutectics gradually aggregate from ion pairs, to clusters with minimal free energy, and finally to a continuous salt phase, leading to the formation of micropores, uniform mesopores, and macropores, respectively; these processes cause BET specific surface area initially to increase but subsequently to decrease. With the mass ratio of ionic liquids to salts at 35% and carbonization temperature at 900°C, the specific surface area of the resultant carbon aerogels reached 2309 m2 g–1. By controlling the carbonization temperature and mass ratio of the raw materials, the hierarchically porous architecture of carbon aerogels can be tuned; this advantage will promote their use in the fields of electrodes and adsorption.

Abstract
 1. Introduction
 2. Experimental
  2.1. Materials
  2.2. Preparation of carbon aerogels
  2.3. Instant observation experiments using visible reaction setting
  2.4. Characterization
 3. Results and Discussion
  3.1. Visual observation of reaction during rising of carbonization temperature
  3.2. Research into process parameters of preparation of carbon aerogels
  3.3. Characterization of carbon aerogels
 4. Conclusions
 References

• Zhen Zhang(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology)
• Junzong Feng(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology) Corresponding Author
• Yonggang Jiang(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology)
• Jian Feng(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology) Corresponding Author