The control of porosity at nano scale in resorcinol formaldehyde carbon aerogels

Abstract

Organic aerogels were synthesized by sol-gel polymerization of resorcinol (R) with formaldehyde (F) catalyzed by sodium carbonate (C) followed by vacuum drying. The influence of the resorcinol/sodium carbonate ratio (R/C) on the porous structure of the resultant aerogels was investigated. The nitrogen adsorption-desorption measurements show that the aerogels possess a well developed porous structure and mesoporosity was found to increase with increasing the R/C ratio. Carbon aerogels were obtained by carbonization of RF aerogels. The carbonization temperature impacts the microstructure of the aerogels by pore transformations during carbonization probably due to the formation of micropores and shrinkage of the gel structure. The results showed that a temperature of 1073 K is more effective in the development of the pore structure of the gel. Activated carbon aerogels were obtained from the CO 2 activation of carbon aerogels. Activation results in an increase in the number of both micropores and mesopores, indicative of pore creation in the structure of the carbon. Activation at higher temperatures results in a higher degree of burn off and increases the pore volume and the surface area remarkably without change of the basic porous structure, pore size, and pore size distribution.

The impact of deuterium oxide on the properties of resorcinol-formaldehyde gels

“…3) and is also classified as Type IV(a) [27] in both cases. It is notable that the family of isotherms obtained for undeuterated RF gels are in agreement with those previously reported in the literature [2,30]. Pore-size distributions are not shown for R/C ratios 300 and 600 due to the lack of a distinct plateau at the higher pressures in the isotherm data.…”

The effects of temperature on the performance of electrochemical double layer capacitors

“…The electrodes for the EDLC test cell were manufactured from resorcinol formaldehyde xerogels [5] dried under vacuum, milled, carbonised at 800 • C, milled and activated with CO 2 at 800 • C. The xerogel was mixed with 10% carbon black and 10% Kynar binder in acetone and spread on to aluminium foil in a 200 m layer, allowed to dry and cut into 1.3 cm diameter discs.…”

The influence of thermal treatment on the electrochemical properties of carbon–Ni–Pd composites

“…Carbon gels are formed during the pyrolysis of RF aerogels. The structure and properties of carbon gels depend on the polymerization conditions [9][10][11][12] and the ratio of the substrates R/C [13,14].…”