Production of TiO2 Coated Multiwall Carbon Nanotubes by the Sol-Gel Technique

Abstract

In recent years, efforts in developing high strength-low density materials are increasing significantly. One of the promising materials to attend this demand is the carbon nanotube (CNT), to be used mainly as a reinforcing phase in lightweight metal matrix composites (MMC). In the present work, the sol-gel technique has been employed to obtain TiO 2 coating on the surface of commercial multiwall carbon nanotubes (MWCNT). The aim of such coating is to improve the thermal stability of MWCNT in oxidize environment, which is necessary in most of MMC processing routes. Calcination in inert atmosphere was performed in order to crystallize a stable coating phase. The hybrid CNT/TiO 2 nanocomposite was characterized by X-Ray Diffractometry (XRD), Raman spectroscopy, Thermogravimetry (TGA) and Field Emission Gun -Scanning Electron Microscopy (FEG-SEM). The coating structure was observed to change from anatase to rutile, as the calcination temperature increases from 500 to 1000ºC. Results from thermogravimetric analysis showed that the samples calcined at 1000 ºC were more resistant to oxidation at high temperatures.

Production of green diesel from catalytic deoxygenation of chicken fat oil over a series binary metal oxide-supported MWCNTs

“…The MWCNT support was thermally stable up to 500 C, while Ni 10 -Mn 10 /MWCNT, Ni 10 -Cu 10 /MWCNT, Ni 10 -Mg 10 /MWCNT and Ni 10 -Ce 10 /MWCNT showed weight loss changes at 400 C. The weight loss within the temperature the range 400-650 C is typically due to the oxidation of MWCNTs. 36 The reduction in thermal stability of MWCNTs by incorporation of binary metal oxide promoters is due to the presence of structural imperfections (vacancies and dislocations). 37 The Ni 10 -Mg 10 / MWCNT showed additional weight losses at a lower temperature (<300 C), which is attributed to the vaporisation of physically adsorbed water.…”

Carbon/Graphene-Modified Titania with Enhanced Photocatalytic Activity under UV and Vis Irradiation

“…It is known that D and G bands of carbon structures are located at ca. 1350 and 1600 cm −1 , and G band is common for all sp2 carbon forms giving information on the in-plane vibration of sp2 bonded carbon (tangential stretching mode of C=C bond), whereas D band is associated with structural disorder (the presence of sp3 defects) [19,44]. Therefore, it was confirmed that TiO 2 (C) was surface modified with carbon species, correlating well with high absorption at vis range (Figure 3a).…”

“…Unfortunately, it was difficult to detect two characteristic peaks for graphene-kind structure at ca. 1304-1349 cm −1 and 1588-1601 cm −1 (as reported for graphene, GO, rGO, multiwall carbon nanotubes (MWCNT) of graphitic nature [19,20,23,44]), probably due to its low content. Interestingly, low-intensity peaks at ca.…”

Pulsed Discharge Plasma in High-Pressure Environment for Water Pollutant Degradation and Nanoparticle Synthesis

“…Furthermore, the analysis period is also relatively short [43,[102][103][104]. It seems that the absorption peaks at 1340, 1582, and 2670 cm −1 corresponded to the D, G, and 2D band modes, respectively, which were clearly observed in the Raman spectra of solution product, where the D band exhibits disordered carbon mode and the G band exhibits ordered carbon mode [105,106]. Obviously, the absorption peak at around 2920 cm −1 , which was associated with the hydroxyl group, was also found in this Raman spectrum [107][108][109].…”