Surface Structure of Untreated Parallel and Fishbone Carbon Nanofibres: An Infrared Study

Abstract

Parallel and fishbone carbon nanofibres have an interesting and varied surface. Although HRTEM (see image) shows some detail, the characterisation provided by infrared spectroscopy reveals a wealth of defect‐rich structures.

TEM and XPS studies to reveal the presence of cobalt and palladium particles in the inner core of carbon nanofibers

“…3) shows that the fibers are indeed of the fishbone type, however, with irregularities in the graphene sheets. The distance between the graphene sheets is about 3.4 Å , a value which corresponds well with values that were obtained with XRD and to that reported by other authors [3,8,35]. The core in CNF a.s. is either empty, or filled by an amorphous carbon phase or highly disordered graphene sheets.…”

“…The macroscopic CNF bodies consist of skeins of interwoven fibers [1,3,7]. The core of the individual fibers most probably consist of highly disordered graphene sheets or an amorphous carbon phase which is removed upon HNO 3 treatment [1,8]. Only recently, it has been shown that it is also possible to grow in a single-step fishbonetype CNF with a hollow core throughout the length of the fiber [9][10][11].…”

Surface Oxidation of Carbon Nanofibres

“…Figures 5 and 6 show the infrared spectra for the oxidation of parallel fibres in HNO 3 and HNO 3 /H 2 SO 4 for 30 min. The band at 1454 cm −1 in the spectrum of the untreated fibres is attributed to CH 2 /CH 3 bending vibrations 25, 29, 33. Upon oxidation in acid, the appearance of the carbonyl/carboxy band at 1714 cm −1 is accompanied by an increase in intensity of the 1200 cm −1 absorption due to CO and OH groups.…”

“…All band assignments are summarised in Table 2, and all changes observed in the IR spectra after the different oxidative treatments are summarised in Table 3. The assignment of the bands of the untreated fibres is discussed elsewhere 25. The absorptions at 1633 and 1384 cm −1 are due to water and nitrate, respectively, adsorbed on the KBr and can be disregarded 19, 26–28.…”

“…Figure 4 shows the 3200–2700 cm −1 region of the untreated and the oxidised (HNO 3 /H 2 SO 4 , 60 min) fishbone fibres. The bands at 2947, 2912, and 2841 cm −1 arise from CH 2 /CH 3 stretching vibrations 25, 29. After oxidation, the intensity of the CH 2 /CH 3 minima of the treated sample is decreased considerably.…”