Multiwalled Carbon Nanotube‐TiO₂ Nanocomposite for Visible‐Light‐Induced Photocatalytic Hydrogen Evolution

Abstract

Multiwalled carbon nanotube- (MWCNT-) TiO2nanocomposite was synthesized via hydrothermal process and characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, field emission scanning electron microscope, thermogravimetry analysis, and N2adsorption-desorption isotherms. Appropriate pretreatment on MWCNTs could generate oxygen-containing groups, which is beneficial for forming intimate contact between MWCNTs and TiO2and leads to a higher thermal stability of MWCNT-TiO2nanocomposite. Modification with MWCNTs can extend the visible-light absorption of TiO2. 5 wt% MWCNT-TiO2derived from hydrothermal treatment at 140°C exhibiting the highest hydrogen generation rate of 15.1 μmol·h−1under visible-light irradiation and a wide photoresponse range from 350 to 475 nm with moderate quantum efficiency (4.4% at 420 nm and 3.7% at 475 nm). The above experimental results indicate that the MWCNT-TiO2nanocomposite is a promising photocatalyst with good stability and visible-light-induced photoactivity.

Catalytic and Photocatalytic Nitrate Reduction Over Pd-Cu Loaded Over Hybrid Materials of Multi-Walled Carbon Nanotubes and TiO2

“…As expected, the presence of CNT led to a rise of light absorption in the visible spectral region, increasing with the CNT content on the composite catalysts up to a CNT load of 50 wt.%. This behavior has been attributed not only to the capacity of CNT to absorb visible light but also to an increment of surface electronic species availability and mobility in the composite catalysts due to the introduction of CNT, as already reported in previous studies (Silva and Faria, 2010; Dai et al, 2014). A further increase in the CNT content did not produce any effect on the optical absorption of the composite materials.…”

Photocatalytic production of hydrogen from methanol and saccharides using carbon nanotube-TiO2 catalysts

“…A synergy effect was observed, which was attributed to the action of SWCNT as sinks for the electrons photogenerated upon TiO 2 excitation. Multi-walled carbon nanotube (MWCNT)-TiO 2 composites loaded with Pt nanoparticles have been used for the photocatalytic H 2 generation from triethanolamine solutions under both UV and visible-light irradiation [17,18]. While bare TiO 2 and MWCNT alone didn't show any catalytic activity, MWCNT-TiO 2 composites promoted the photocatalytic production of H 2 under visible light conditions, which was ascribed to an increase in light absorption and charge separation in the composite material.…”

Carbon Nanotubes based Nanocomposites as Photocatalysts in Water Treatment

“…Typically, the final materials obtained are mostly amorphous TiO2 with seeds of anatase regardless the chosen conditions and chemistry. Thus, a further heat treatment that occurs at 300-500 °C in air is required to fully crystallize the TiO2 coating on CNTs and avoid the burnout of the CNTs [47]. In contrast with other methods, the advantages of the composites prepared by hydrothermal methods are found to give better results, including less agglomeration among particles, narrow particle size distribution, and controllable phase homogeneity and particle morphology.…”