Heterogeneous Carbon Gels: N-Doped Carbon Xerogels from Resorcinol and N-Containing Heterocyclic Aldehydes

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• 作者：Wojciech Kici艅ski ; Ma艂gorzata Norek ; Bart艂omiej J. Jankiewicz
• 刊名：Langmuir
• 出版年：2014
• 出版时间：December 2, 2014
• 年：2014
• 卷：30
• 期：47
• 页码：14276-14285
• 全文大小：580K
• ISSN：1520-5827

文摘

Direct, acid (HCl) initiated sol鈥揼el polycondensation of resorcinol with pyrrole-2-carboxaldehyde or its derivative N-methyl-2-pyrrolecarboxaldehyde yields thermosetting phenolic organic gels with N-content of up to 8.4 wt %. After carbonization, sturdy monoliths of N-doped carbon xerogels with N-content of up to 8 wt % are produced. The morphology and porosity of the doped carbons can be tuned by the solvent composition and the amount of polymerization catalyst used. An increase in carbonization temperature from 600 to 1000 掳C strongly affects the carbon gels鈥?microporosity, resulting in a decrease in N₂ adsorption capacity, but a significant increase in H₂ adsorption capacity (at 鈭?96 掳C). The growing H₂ sorption capacity with the decreasing specific surface area (measured by N₂) is related to the gradual shrinkage of the carbon xerogel matrix and narrowing of the small micropores. In addition, it is demonstrated that pyridine-based heterocyclic aldehydes, that is, 2- or 4-pyridinecarboxaldehyde, condensate with resorcinol in basic conditions (KOH, NH₄OH). However, in this case, monoliths cannot be produced and powders/rigid solid precipitates are obtained instead. If NH₄OH is used as a sol鈥揼el polycondensation catalyst, N-doped foams are obtained as a final carbonaceous product.