Functionalisation and chemical characterisation of cellulose-derived carbon aerogels

Designing Nanostructured Carbon Xerogels

“…melamine, urea, cellulose acetate, etc. (Gryzb et al, 2010;Long et al, 2008b). Rather than in post-synthesis treatment, this is a modification of the synthesis receipt and therefore, the polymerization process would vary since the initial reactants are different.…”

“…(Czzakel et al, 2005;Dingcai & Rouwen, 2006;Long et al, 2008aLong et al, , 2008bPekala et al, 1995 ;Scherdel & Reichenauer, 2009). Amongst all the possible variations, probably the most commonly synthesized carbon gels are those based on resorcinol and formaldehyde, although in order to reduce the cost of the materials involved in the synthesis process, some less expensive precursors, such as phenol (Mukai et al, 2005a;Scherdel & Reichenauer, 2009;Teng & Wang, 2000) or cellulose (Gryzb et al, 2010), have attracted interest in recent years. Another important parameter for the preparation of carbon gels is the reaction media because there are several available solvents such as deionised water (Job et al, 2004;Pekala, 1989;Zhu et al, 2007), acetone (Berthon et al, 2001) or methanol (Zubizarreta et al, 2008a).…”

“…Unlike the partial blockage of the pores produced in oxidative processes with concentrated HNO 3 , the HNO 3 -hydrothermal method not only maintained the porous texture of carbon xerogels but also, when the operating temperature was fixed at 200 ºC, there was even an increase in the specific surface area of carbon xerogels oxidized with a high concentration of HNO 3 solution. Another published study covering several types of carbon xerogels post-treatments, was performed recently by Grzib and co-workers (Gryzb et al, 2010). A series of nitrogen and oxygen functionalised carbon xerogels were synthesized by means of different oxidative processes with HNO 3 and H 2 O 2 , treatments with gaseous ammonia at high temperature and co-heating of carbon xerogels with melamine.…”

“…For example, carbon gel functionalisation can be carried out with post-synthesis treatments, such as oxidation using different oxidizing agents, HNO 3 , H 2 O 2 , air, etc. (Gryzb et al, 2010;Mahata et al, 2008), treatments with compounds such as ammonia, melamine or ammonia borane (Gorgulho et al, 2009;Pérez-Cadenas et al, 2009;Sepheri et al, 2009), with the aim of incorporating nitrogen and borane groups, respectively, into the structure of carbon gels. Alternatively, heteroatoms can be directly added during the synthesis using heteroatom-containing polymeric precursors, i.e.…”

“…In other words, the porosity may be tripled which is a great advantage in applications that require highly porous materials such as supercapacitors, hydrogen storage or catalysis. There are several published works that deal with ways to modify the chemical nature of carbon gels by means of doping or oxidizing processes in order to widen their range of applications (Gryzb et al, 2010, Job et al, 2007bLee et al, 2011;Sepheri et al, 2009;Silva et al, 2009;Zubizarreta et al, 2010). The porous texture of carbon gels is a crucial property in most of the fields of application.…”