Easy and convenient synthesis of CNT/TiO2 nanohybrid by in-surface oxidation of Ti3+ ions and application in the photocatalytic degradation of organic contaminants in water

Abstract

Organic/inorganic nanohybrid materials are a new type of functional materials that have attracted great interest in the last decades, due to their exceptional optical, electrical, mechanical, thermal and catalytic properties. The present study reports a modified sol gel method, so-called “in-surface oxidation of Ti3+ ions”, for the synthesis of carbon nanotube/titania (CNT/TiO2) nanohybrids. The CNT/TiO2 nanohybrid material was synthesized with different volumes of TiCl3 as the titanium source. To analyze their morphology, textural, surface crystallographic and optical properties the materials were characterized by Scanning and Transmission Electron Microscopy (SEM and TEM), X-ray Diffraction (XRD), Fourier Transformed Infrared (FT-IR), Energy-Dispersive X-ray analysis (EDX), X-ray Photoelectron Spectroscopy (XPS), Raman, BET and UV–Vis Diffuse Reflectance Spectroscopy (UV-DRS). The morphological, physico-chemical and textural aspects to account for the results are exhibited. Interestingly, the TiO2 nanoparticles are well dispersed on CNT surface of the nanohybrid. More interestingly, doping of nitrogen atoms in CNT during the Ti3+ oxidation step increases the nucleation sites on CNT surface. The quality of the TiO2 coating depends on various reaction conditions such as temperature and TiCl3 concentration. The photocatalytic performance of the photocatalysts was tested by degradation of methyl orange. The experimental results indicate that the C–O–Ti, N–Ti–O and Ti–C bonding between CNT and TiO2 in the nanohybrid material promoted a good photogenerated charge separation, thus greatly improving the photocatalytic activity of the nanohybrid photocatalyst, when compared to pure TiO2.