The effects of synthesis procedures on the morphology and photocatalytic activity of multi-walled carbon nanotubes/TiO₂nanocomposites

Abstract

This study investigates the microstructures of multi-walled carbon nanotubes (MWNTs)/TiO(2) nanocomposites, obtained by sol-gel and hydrothermal processes. The synthesized nanocomposite materials were characterized by x-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) adsorption analysis, transmittance electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, and x-ray photoelectron spectroscopy (XPS). The effects of the synthetic procedures and MWNTs on the morphology and photocatalytic activity of the nanocomposites were studied. The photocatalytic activity of the MWNTs/TiO(2) nanocomposite was elucidated based on the photooxidation of NO(x) under UV light illumination. A fleck-like and well dispersed TiO(2) microstructure on the surface of the MWNTs was observed in the sol-gel system, while compact and large aggregated particles were found in the hydrothermal procedure. The nanocomposite prepared by the sol-gel system exhibits better photocatalytic activity for NO oxidation (from 20.52 to 32.14%) than that prepared by the hydrothermal method (from 22.58 to 26.51%) with the same MWNT loading (from 0 to 8 wt%), respectively. The optimal MWNT content in the nanocomposite was considered at 8 wt%. Additionally, results confirm that the introduction of MWNTs will cause the NO(2) to be more consumed than NO in the photocatalytic experiments, leading to more complete NO(x) photooxidation. These observations indicate that the different TiO(2) distributions on the MWNT surfaces and MWNT contents in the materials would determine the morphology, the physicochemical and photocatalytic characteristics for the nanocomposite materials.

A review on the application of inorganic nano-structured materials in the modification of textiles: Focus on anti-microbial properties

“…The production of Pt/TiO 2 [100], TiO 2 /chitosan nano-composites [105], TiO 2 /SiO 2 [106], CNTs-TiO 2 composites [107][108][109], TiO 2 -hydroxyapatite [110] and many others has also been reported.…”

Effects of processing parameters on the synthesis of TiO2 nanofibers by electrospinning

“…Solution-solid methods [10], vapor-liquid-solid growth [11,12], anodizing [13,14] and solvothermal synthesis [15] have been often used. In recent years, electrospinning has been widely used to synthesize nanofibers of oxide materials [16,17].…”

Preparation and Photocatalytic Performance of MWCNTs/TiO2Nanocomposites for Degradation of Aqueous Substrate

“…A complete photocatalytic process is generally divided into three stages, including light harvesting, separation of photogenerated charges, and interfacial reactions [1,11]. So it is important for high-efficiency photocatalysts to have a fine implementation at each stage.…”

“…Nanometer titanium dioxide (nano-TiO 2 ) was one of the most popular photocatalysts with the characters of stability, low cost, and nontoxicity and applied widely for treating organic pollutants in the fields of environmental purification [7][8][9][10]. However, due to the wide band gap (3.0-3.2 eV), nano-TiO 2 is only capable of absorbing UV light, accounting for a small fraction (5%) of the sun energy, and the TiO 2 /UV system has been widely investigated in heterogeneous photocatalysis [1,11]. Besides, as the photocatalytic activity of TiO 2 is also limited by the photogenerated electron-hole pairs recombination, a suppression of this undesired reaction is an important factor for achieving a high catalytic activity [12,13].…”