Visible light assisted photocatalytic degradation of organic dyes on TiO2–CNT nanocomposites

Abstract

Carbon nanotubes (CNTs) uniformly decorated with nano-anatase TiO 2 particles corresponding to different TiO 2 -CNT weight ratios (up to 90 % TiO 2 :10 % CNT) were prepared by employing sol-gel process. The nanocomposites were characterized by X-ray diffraction, IR, Raman, Scanning electron microscopy, Transmission electron microscopy, Photoluminescence, BET surface area and diffuse reflectance measurements. The composites show visible light assisted photocatalytic property, for example, the 90 % TiO 2 -10 % CNT composite completely degrades Indigo Carmine dye within 1 h of exposure to visible light. Similarly, Orange G and Congo Red dyes were decomposed within 2 h under visible light irradiation. The excellent visible light photocatalytic property of the composite is attributed to the synergetic effect of photoexcitation and photosensitization. This is due to the special nanoarchitecture wherein TiO 2 nanoparticles are anchored to CNT surface that provides high specific interfacial area for photon absorption and electron trapping.

Rhodamine B Photodegradation in Aqueous Solutions Containing Nitrogen Doped TiO2 and Carbon Nanotubes Composites

“…Figure 9a highlights that regardless of the carbon nanotubes type, i.e., SWNTs, DWNTs, or MWNTs, the presence of carbon nanotubes (with the concentration of 5 wt.%) into TiO 2 :N/CNTs samples dispersed in RhB aqueous solutions does not induce large variations in the UV-VIS spectra of the samples recorded prior to exposure to UV light. were added to TiO2:N can be attributed to faster electron-hole recombination with increases of the SWNT concentration in the TiO2:N/SWNT mixture [21]. A higher SWNT concentration can block the irradiation and obstruct charge carrier generation; in addition, SWNTs can form aggregates due to van der Waals interactions between individual tubes and act as a screening agent for TiO2:N, blocking its exposure to UV light.…”

Mechanistic insight of structural and optical properties of BiOCl in the presence of CNTs and investigating photodegradation of phenol by BiOCl/CNT composites

“…For long, CNTs have benetted several photocatalysts, including TiO 2 and Bibased photocatalysts, in terms of extending their light-harvesting response from UV to visible light region. 15,16 CNTs due to their good electrical conductivity and adsorption of reactants, acts as an electron sink or as a photosensitizer. For instance, in a study of multiwalled carbon nanotube, TiO 2 and Ni composite catalyst (MWNT-TiO 2 :Ni) by Ou and coworkers, MWCNT acted as a photosensitizer by absorbing the light and transporting the photogenerated electrons into the conduction band of TiO 2 particles and further to isolated Ni particles which reduced the water molecules to H 2 .…”

Sonochemical/hydration—dehydration synthesis of Pt—TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

“…47 Photoluminescence is a powerful tool to probe the electronhole pair formation and their recombination at surfaces. 48,49 The PL measurements were carried out with pure TiO 2 , Pt/TiO 2 and with loading and unloading Pt on the TiO 2 /fCNTs (fSWCNTs, fMWCNTs) composites, as shown in Fig. 6.…”