Structure and electrochemical properties of carbon aerogels polymerized in the presence of Cu2+

Copper-loaded organic aerogels were prepared by sol–gel polymerization of resorcinol and formaldehyde in a solution of Cu(NO3)2. Carbon aerogels derived from the heat-treatment of the organic precursor kept their particulate structure, according to TEM observations. The particle size in Cu-loaded carbon aerogel samples becomes larger with a higher concentration of Cu incorporated into their texture, due to the presence of Cu2+ rather than the pH conditions in the sol–gel process. The nitrogen adsorption measurement of Cu-loaded samples showed their characteristic pore structure, i.e., a combination of microporosity and mesoporosity both developed in their texture. Especially, their advanced microporosity, which was still found after carbonization at 1273 K, was very unique, considering that micropores in organic aerogels often decreased in size during heat-treatment around this temperature range. This microporosity could be related to their stacking structure of aromatic layers revealed by STAC–XRD analysis, indicating a looser packing of aromatic layers in their structure. Application of Cu-loaded samples to electric double-layer capacitor is also discussed from the viewpoint of the amount of Cu as well as the pore structure of the samples.