Carbon xerogels: Nano- and adsorption textures, chemical nature of the surface and gas chromatography properties

Zheivot, V. I.; Molchanov, V. V.; Зайковский, В. И.; Krivoruchko, V. N.; Zaitseva, N. A.; Shchuchkin, M. N.

doi:10.1016/j.micromeso.2009.10.002

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…Due to their developed porous structures, such materials show no mass transfer limitations, which is quite important for their application in separation processes. In gas chromatography, CXs demonstrate adsorption properties similar to those of other carbon materials [148]. They can be applied for the analysis of light hydrocarbons and the gaseous products of many catalytic reactions.…”

Section: Adsorbentsmentioning

confidence: 99%

Resorcinol–Formaldehyde-Derived Carbon Xerogels: Preparation, Functionalization, and Application Aspects

Veselov,

Vedyagin

2023

Materials

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Carbon xerogels (CXs) are materials obtained via the pyrolysis of resins prepared via the sol–gel polycondensation of resorcinol and formaldehyde. These materials attract great attention as adsorbents, catalyst supports, and energy storage materials. One of the most interesting features of CXs is the possibility of fine-tuning their structures and textures by changing the synthesis conditions in the sol–gel stage. Thus, the first part of this review is devoted to the processes taking place in the polycondensation stage of organic precursors. The formation of hydroxymethyl derivatives of resorcinol and their polycondensation take place at this stage. Both of these processes are catalyzed by acids or bases. It is revealed that the sol–gel synthesis conditions, such as pH, the formaldehyde/resorcinol ratio, concentration, and the type of basic modifier, all affect the texture of the materials being prepared. The variation in these parameters allows one to obtain CXs with pore sizes ranging from 2–3 nm to 100–200 nm. The possibility of using other precursors for the preparation of organic aerogels is examined as well. For instance, if phenol is used instead of resorcinol, the capabilities of the sol–gel method become rather limited. At the same time, other phenolic compounds can be applied with great efficiency. The methods of gel drying and the pyrolysis conditions are also reviewed. Another important aspect analyzed within this review is the surface modification of CXs by introducing various functional groups and heteroatoms. It is shown that compounds containing nitrogen, sulfur, boron, or phosphorus can be introduced at the polycondensation stage to incorporate these elements into the gel structure. Thus, the highest surface amount of nitrogen (6–11 at%) was achieved in the case of the polycondensation of formaldehyde with melamine and hydroxyaniline. Finally, the methods of preparing metal-doped CXs are overviewed. Special attention is paid to the introduction of a metal precursor in the gelation step. The elements of the iron subgroup (Fe, Ni, Co) were found to catalyze carbon graphitization. Therefore, their introduction can be useful for enhancing the electrochemical properties of CXs. However, since the metal surface is often covered by carbon, such materials are poorly applicable to conventional catalytic processes. In summary, the applications of CXs and metal-doped CXs are briefly mentioned. Among the promising application areas, Li-ion batteries, supercapacitors, fuel cells, and adsorbents are of special interest.

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Section: Adsorbentsmentioning

confidence: 99%

Resorcinol–Formaldehyde-Derived Carbon Xerogels: Preparation, Functionalization, and Application Aspects

Veselov,

Vedyagin

2023

Materials

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“…In fact, Zheivot et al (Zheivot et al, 2010) published in 2010 a study about the production of several phenol-formaldehyde carbon xerogels and their use as adsorption materials in gas chromatography. Results reported showed that microporous carbon xerogels can be prepared varying the synthesis conditions and they can be successfully used as adsorbents to concentrate the impurities of light hydrocarbons and gaseous products of many catalytic reactions.…”

Section: Other Applicationsmentioning

confidence: 99%

“…The combination of these properties makes carbon gels the perfect candidates for diverse applications such as supercapacitors, fuel cells, desalination systems, catalyst supports, liquid and gas-phase adsorbents, etc. (Calvo et al, 2008;Frackowiak & Béguin, 2001;Moreno-Castilla et al, 2005;Zheivot et al, 2010;Zubizarreta et al, 2010). However, despite the large number of advantages associated with carbon gels, there are still some applications where it is preferable to use activated carbons as a result of their low production costs.…”

Section: Introductionmentioning

confidence: 99%