Lookup NU author(s): Emeritus Professor Mark Thomas
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X-ray absorption near edge structure (XANES) was used to investigate the fate of nitrogen functional groups in carbons derived from acridine, carbazole, and polyacrylonitrile during carbonization. Acenaphthylene and poly(vinyldene chloride) carbons with nitrogen incorporation by ammonia treatment at elevated temperatures were also studied. In general, the nitrogen XANES data provided more detail than the corresponding X-ray photoelectron spectroscopy (XPS) results and confirm the overall picture obtained from XPS involving the greater stability of pyridinic and quaternary nitrogen functionalities with increasing severity of pyrolysis. Partial gasification of the carbons in 20% oxygen/argon produced a new peak or greatly increased the intensity of an existing nitrogen XANES peak at ∼401.5 eV which was independent of the nitrogen functionality originally present in the carbon. The oxygen XANES spectra showed that carbonyl and carboxylic acid/acid anhydride functionality were also present on the surface of carbons partially gasified with oxygen. The XANES studies have also been compared with the temperature-programmed combustion and temperature programmed desorption studies of the carbons. The results are consistent with the presence of pyridone functionality in the partially gasified carbons. The overlap of bands may obscure the interpretation of data from X-ray absorption spectroscopy, and information is required from a number of techniques in order to provide a more detailed view.
Author(s): Zhu Q, Money SL, Russell AE, Thomas KM
Publication type: Article
Publication status: Published
Print publication date: 02/04/1997
ISSN (print): 0743-7463
ISSN (electronic): 1520-5827
Publisher: American Chemical Society
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