Textural and Adsorption Analysis of Nanocarbon Particles

Abstract

In this present work, the characterization of the nanocarbon material which is multi-walled carbon nanotube (MWCNT) and carbon nanofiber (CNF) was investigated using nitrogen gas adsorption technique, Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The characterization testing was performed to study the surface species of the materials which including morphology and specific surface area (pore type, pore volume, surface area). Three nanocarbon were characterized in this research which is 1) MWCNT-OH, 2) Modified MWCNT and 3) Commercial CNF. The porosity existence of this nanocarbon was analyzed by using BET method and the surface area is measured by diameter and depth of the existed pores. A comparative study of the adsorption shows that all the nanocarbon isotherm can be classified as Type IV which generally associated with mesoporous adsorbents. Density Functional Theory (DFT) plot which calculates the porosity population revealed the existence of micropore and mesopore for all the tested sample. Meanwhile, the BET surface area reading shows that MWCNT-OH has the largest surface area (MWCNT-OH > Commercial CNF > Modified MWCNT) compared to other nanocarbon. Pore volume plays a significant role in affecting the BET surface area as the MWCNT-OH has the largest pore volume which contributes to the high surface area. The morphology and functionalized-group attachment on the nanocarbon surface was characterized using FESEM and FTIR. All the FESEM images demonstrated agglomerate carbon nanotube and nanofibers, primarily with non-uniform tubular structure. FTIR spectra revealed that the Modified MWCNT gives the highest hydroxyl group –OH with the value of 3442 cm-1 peaks followed by MWCNT-OH and Commercial CNF. Overall, this finding generated a great interest in studying the properties of surface porosity and particle size for materials engineering.