Raman spectroscopic study of effect of steam and carbon dioxide activation on microstructure of polyacrylonitrile‐based activated carbon fabrics

Abstract

This work presents the different effects of steam and carbon dioxide activation on the microstructure of an oxidized polyacrylonitrile (PAN) fabric. An investigation was conducted on a series of carbonized fabrics and two series of activated carbon fabrics. The fabrics were activated by steam and carbon dioxide using heat‐treatment temperatures of 900–1100°C. Steam and carbon dioxide developed the microstructure initially present in the PAN‐based activated carbon fabrics, but with different effects. These fabrics in the form of fabric and powder were examined by X‐ray diffraction and Raman spectrometry. This study indicated that carbon dioxide only reacted with the crystalline edges or the irregular carbon on the fiber surface and that the inside structure of the fibers was not greatly affected. When the fabrics were activated using steam, water molecules reacted not only on the fiber surface but also with the carbon at the crystal edge and/or the nonregular carbon in the fibers, which led to communicating pore structures on the surface and in the inner portions of the fiber. This activation also promoted the denitrogenation reactions. Because of these structures and reactions, the activated carbon fabrics, which were activated by steam, had the highest stacking height for carbon layer planes (Lc), the highest number of layer planes (Lc/d002), the highest oxygen content, the largest crystal size (La), and the highest density over the other samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1090–1099, 2001

High Pseudocapacitance from Ultrathin V2O5Films Electrodeposited on Self‐Standing Carbon‐Nanofiber Paper

“…[ 35 ] Raman peaks corresponding to the G-band (1584 cm − 1 ) and D-band (1352 cm − 1 ) of the carbon layers can be observed in both of the graphs, with and without oxide deposition. [ 36 ] The XRD and the Raman spectra show the crystallinity and purity of the V 2 O 5 . In the Raman spectrum, there is no characteristic peak from VO 2 (i.e., from the vanadium + 4 oxidation state), whereas V 2 O 5 peaks are present, [ 37 ] which clearly indicates the phase purity of the V 2 O 5 .…”

Carbon‐Based Electrochemical Capacitors

“…[211][212][213][214][215][216] The electrodeposition technique was considered to be among the most useful techniques to deposit conducting polymers, such as PANI, on different carbon materials to fabricate different types of PANI/carbon composites. [227,228] 6. A porous carbon nanofiber paper electrode without any binder or percolator was obtained by activation of PAN-based nanofiber paper at temperatures from 700 to 1000 8C in a CO 2 atmosphere.…”

Adsorption of heavy metals onto activated carbons derived from polyacrylonitrile fiber

“…ACF can be produced from coal [11] and petroleum pitches [12,13], rayon [14], polyacrylonitrile (PAN) [15][16][17] and phenolic resin [18] through high temperature gasification in steam or CO 2 . Ko et al [19] reported that steam was better than CO 2 for generating a well-distributed surface area of ACF. Chemical activation by NaOH, KOH, H 3 PO 4 or ZnCl 2 , however, has not been recommended because despite enhancing the porosity, the reagent may also destroy the fiber morphology [17,20].…”