As-prepared Carbon Nanofibers Research Articles

Purification of carbon nanofibers with hydrogen peroxide

As-prepared carbon nanofibers (CNFs) contained some carbonaceous impurities of amorphous carbon and incompletely grown carbon nanofibers. Removal of those impurities using hydrogen peroxide as a reducing agent was carried out. Amorphous carbon synthesized in carbon nanofiber preparation and incompletely grown carbonaceous materials were distinctly removed in this purification process performed in hydrogen peroxide. The morphological changes of as-prepared and hydrogen peroxide treated carbon nanofibers were investigated by FE-SEM and TEM observations. After that purification, amorphous carbons were markedly removed by reduction and carbon nanofibers without carbonaceous impurities were obtained successfully. The X-ray diffraction results show that the purification method using hydrogen peroxides was very stable for carbon nanostructures.

Purity enhancement and electrochemical hydrogen storage property of carbon nanofibers grown at low temperature

Carbon nanofibers (CNFs) were prepared on Ni metal catalyst at 500°C by thermal CVD using acetylene as a carbon source in fixed bed reactor. To obtain pure CNFs without metal catalyst, as-prepared CNFs were treated in hot nitric acid. The morphological changes for as-prepared and nitric acid treated CNFs were investigated by means of SEM and TEM. After this purification process, the eliminated Ni particles using catalyst of CNFs growth was explained by TGA analysis. The improved discharge capacity attributed to the hydrogen storage amount was systemically discussed in terms of the elimination of metal catalyst by CNFs purification in hot nitric acid.

Clinical syndromes with dilation of the occipital horns of the lateral ventricles

The objectives of the present study are (i) fabrication of multiwalled carbon nanotubes (MWCNT)/Cu composites via electrospinning method, better dispersion, and heat treatment; and (ii) to examine the effect of the heat treatment on the mechanical, thermal, and electrical properties of the electrospun fibers. In this study, we have fabricated polyacrylonitrile (PAN) based MWCNT/Cu carbon nanofiber composites by electrospinning method with different weight percentage of CNT (0.1%, 0.3%, 0.5%). The MWCNT/Cu composites were aligned in an electrified thin jet during electrospinning. Field Emission Scanning Electron Microscope and High Resolution Transmission Electron Microscopy was used to analyze the morphology of the as-prepared carbon nanofibers. The elemental analyses of fibers were determined by Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy, X-ray Powder Diffraction and X-ray Photoelectron Spectroscopy. Thermogravimetric analysis and mechanical strength were performed to study the thermal and mechanical properties of the nanofibers composites. Electrical conductivity of the as-prepared fibers was studied by four-point probe method. For the composites containing 0%, 0.1%, 0.3%, 0.5 wt% of MWCNT, the electrical conductivity was measured to be 0.021, 0.459, 1.155, 1.479 S cm−1 respectively.