Heterojunction of graphene and titanium dioxide nanotube composites for enhancing photocatalytic activity

Abstract

Herein we studied the structure deformation and photoluminescence properties of titanium dioxide nanotube (TNT) hydrothermally grown on pristine graphene (Gr) surfaces. This Gr/TNT composite shows photocatalytic enhancement in terms of methylene blue degradation efficiency and short saturation time, as a result of heterogeneous junction formation through the interfacial connection of graphene by a facile one-step hydrothermal method. The Gr content within the composites was varied between 0.5 wt.%–8 wt.%, and the sample containing 5 wt% Gr (0.01 g) displayed the highest photocatalytic activity with methylene blue (20 ppm) degradation efficiency of 99.63%. In addition, all the composites exhibited a very short saturation time of ~5 min under sunlight irradiation. The morphological, crystal structural, optical and photocatalytic properties of the composite material were investigated using transmission electron microscopy, scanning electron microscopy, x-ray diffraction, Raman scattering spectroscopy and photoluminescence spectroscopy. The TNTs grown in situ with graphene showed that it enhanced their photocatalytic activity via the reduced carrier recombination rate of TNTs, which was studied by photoluminescence emission measurement. Furthermore, the mechanism by which the combined material properties affect the photocatalytic performance were characterized and clarified.

Facile Hydrothermal Method for Fabrication Seedless ZnO Nanorod/GO Composite on PCB

“…The peaks at 438 cm -1 and 575 cm -1 which belong to characteristic E2 mode (High) and A1 mode (LO) of wurtzite type phase of ZnO [13], [14]. In addition to the two characteristic vertices of the wurtzite hexagonal phase of ZnO, the Raman spectra of ZnO/GO show two major characteristic peaks at ~ 1350 and 1580 cm -1 corresponding to D band and G band of GO, respectively [15,16]. The D band appears due to sp 3 disabilities while G band is due to in plane oscillation of sp 2 carbon atoms and a doubly degenerated phonon mode [13], [17].…”

Engineering of ZnO/Graphene Nanocomposite for Enhancing Visible Photocatalytic Ability

“…It shows that the higher the pH, the higher the MB degradation efficiency was, which indicates that the photodegradation depended on OH À radicals rather than O 2 À ones. [42,43] Thus, the photocatalytic process of the composite was mainly contributed by photogenic holes, which can be proposed from the following reaction…”

Local Surface Plasmonic Resonance, Surface-Enhanced Raman Scattering, Photoluminescence, and Photocatalytic Activity of Hydrothermal Titanate Nanotubes Coated with Ag Nanoparticles

“…The lower the radiative recombination, the longer the carrier lifetime and, thus, the higher the possibility of photoinduced carriers interacting to degrade organic compounds [47]. However, an unwanted case known as nonradiative emission could happen to reduce the PL emission intensity when the coated materials cover the host surface [48]. This phenomenon was called the PL quenching effect, which many previous photocatalytic studies did not pay much attention to whether the decrease of PL emission intensity was because of the charge separation or the PL quenching effect.…”