FTIR Spectroscopy of Multiwalled Carbon Nanotubes: A Simple Approachto Study the Nitrogen Doping

Abstract

The nitrogen doped multiwalled carbon nanotubes (MWNTs) were synthesized by microwave plasma chemical vapor deposition (MPCVD) technique. In this paper, we report the results of FTIR, Raman, and TGA studies to confirm the presence of N-doping inside carbon nanotubes. Fourier transform infrared (FTIR) studies were carried out in the range 400-4000 cm(-1) to study the attachment of nitrogen impurities on carbon nanotubes. FTIR spectra of the virgin sample of MWNTs show dominant peaks which are corresponding to Si-O, C-N, N-CH3, CNT, C-O, and C-Hx, respectively. The Si-O peak has its origin in silicon substrate whereas the other peaks are due to the precursor gases present in the gas mixture. The peaks are sharp and highly intense showing the chemisorption nature of the dipole bond. The intensity of the peaks due to N-CH3, C-N, and C-H reduces after annealing. It is interesting to note that these peaks vanish on annealing at high temperature (900 degrees C). The presence of C-N peak may imply the doping of the MWNTs with N in substitution mode. The position of this intense peak is in agreement with the reported peak in carbon nitride samples prepared by plasma CVD process, since the Raman modes are also expected to be delocalized over both carbon and nitrogen sites it was found that the intensity ratio of the D and G peaks, I(D)/I(G), varies as a function of ammonia concentration. The TGA measurements, carried out under argon flow, show that the dominant weight loss of the sample occurs in the temperature range 400-600 degrees C corresponding to the removal of the impurities and amorphous carbon.

Effect of phenol functionalization of carbon nanotubes on properties of natural rubber nanocomposites

“…The IR spectrum of CNT shows absorption band at 2920 cm −1 which is attributed to asymmetric and symmetric CH 2 stretching, 1698 cm −1 assigned to carboxylic CO stretching and 1097 cm −1 corresponding to CO stretching in alcohols. The presence of these functional groups on the surface of CNT indicates their introduction during removal of metal catalysts in the purification processes of CNT 22, 23. Carboxylic CO stretching peak observed at 1693 cm −1 can be attributed to acid treatment of CNT.…”

FTIR - An Essential Characterization Technique for Polymeric Materials

“…Comparison between spectra of pristine nanotubes and oxidized N-MWCNTs showed that the bands at 1444 cm -1 , 1373 cm -1 and 1251 cm -1 , attributed to vibration of MWCNTs and C-N bonding in N-MWCNTs, were overcome by several vibrations in carbonyl and carboxylic functionalities in the range of 1720 to 1250 cm -1 (Choi et al, 2004;Misra et al, 2007). A strong band appeared from 3600 cm -1 to 3300 cm -1 by the stretching of the bonding -OH of carboxylic group in oxidized nanotubes (Zawadski, 1980;Chen and Wu, 2004).…”

Effect of multiwalled carbon nanotubes incorporation on the performance of porous silicon photodetector

“…This can be ascribed to the hydrophobic adsorbed DMF on the CNTs surface or by -interaction as well as the Columbic or hydrophilic interaction minimization after DMF sonication which de-bundled the CNTs [10]. [11][12][13]. Fig.…”

“…Peaks at 1093 and 1388 cm −1 represent C H symmetrical mode [6,11]. Misra et al identified this peak at 1440 cm −1 as unique to MWCNTs [12]. The band around 1582 cm −1 can be attributed to graphite structure in MWNTs [11] while C C stretching vibration bond appears at ∼1668.43 cm −1 , suggests the formation of carbon nanoparticles [13].…”