The synthesis of carbon nanomaterials using chlorinated hydrocarbons over a Fe-Co/CaCO3 catalyst

Abstract

The effect of chlorine on the morphology of carbon nanotubes (CNTs) prepared from a Fe-Co/CaCO 3 catalyst was investigated using chlorobenzene (CB), dichlorobenzene (DCB), trichlorobenzene (TCB), dichloroethane (DCE), trichloroethane (TCE) and tetrachloroethane (TTCE) as chlorine sources using a catalytic chemical vapour deposition (CCVD) method. Toluene was used as a chlorine-free carbon source for comparison. Multi-walled carbon nanotubes (MWCNTs) were successfully synthesized. The physicochemical properties of the CNTs were studied using transmission electron microscopy (TEM), Raman spectroscopy, thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD) spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. The inner and outer diameters of the MWCNTs increased with an increase in the number of chlorine atoms contained in the reactant. Chlorine incorporation into the MWCNTs was observed by EDS analysis for all reactants. Formation of 'bamboo-like' structures for the MWCNTs generated from TCE and TTCE was also observed, facilitated by the presence of the high percentage of chlorine in these reactants. Numerous MWCNTs revealed the presence of small carbon nanostructures that grew on top of the dominant CNTs, suggesting an unexpected secondary carbon growth mechanism.

Nitrogen inclusion in carbon nanotubes initiated by boron doping and chlorination: Their use as electrocatalysts for oxygen reduction reaction

“…TEM images of purified chlorinated CNTs in the absence of a boron source are presented in Figure 3A for comparison. They revealed entangled hollow CNTs, some with secondary growth of carbon nanofiber on their surface, as reported previously (Maboya et al, 2016). The absence of kinks, elbows, bamboocompartments, and Y-junctions in the materials generated in the absence of boron (Figure 3A) confirms that indeed boron was incorporated in the materials presented in Figure 2.…”

“…A weak shoulder peak was also observed at 2θ = 50 °corresponding to the Fe 3 C diffraction pattern, which also shifted to higher theta degrees. The presence of Fe 3 C was discussed in the previous studies as arising from the residual metal catalyst that remained after purification on the surface and some embedded inside the chlorinated CNTs (Maboya et al, 2016). The XRD pattern of the chlorinated B-CNTs showed additional diffraction peaks together with the graphitic peaks at 30 and 50 °, which revealed that boron was successfully incorporated into the CNTs (Figure 5A).…”

Solid waste-derived carbon nanomaterials for supercapacitor applications: a recent overview

“…in drug delivery, bio-imaging [32][33][34], medicinal biology [35][36][37][38], aerospace [39,40], new age weapon technology [41,42] etc. Numerous, theoretical approaches have been made by researchers for analysis of waste based CNMs utilized in various applications, by functionalization and doping possibilities with various metals [43,44], metal oxide [45,46], non-metals [47,48] or by strong surface interactions with organic reagents [49,50], conductive polymer incorporation [51,52] etc. Moreover, it has been reported that the functionalized CNMs are stronger candidates for various uses, in comparison to non-functionalized ones, as they have aggregation problem [53,54].…”

Carbon Nanotubes (CNTs) from Synthesis to Functionalized (CNTs) Using Conventional and New Chemical Approaches

“…Otherwise, to study the effect of chlorine on morphology of MWCNTs, Maboya et al synthetized chlorinated carbon nanomaterials using different chlorine sources: chlorobenzene (CB), dichlorobenzene (DCB), trichlorobenzene (TCB), dichloroethane (DCE), trichloroethane (TCE), and tetrachloroethane (TTCE) over a Fe-Co/CaCO 3 catalyst. The increase of inner and outer diameters of MWCNTs was observed due to increase content of chlorine resulting in bamboo structure, showing that MWCNT is strongly generated between TCE and TTCE [174]. Furthermore, to understand the chlorine behavior, Ma et al reported adsorption and desorption of chlorinated compounds to MWCNTs using trichloroethylene (TCE), 1,1,1-trichloroethane (1,1,1-TCA), and 1,s3,5-trichlorobenzene (1,3,5-TCB), so adsorption capacities of chlorinated compounds to MWCNTs are depending on molecular structure of reactant up to 96.8% for TCA and the treatment technique [175].…”