In Situ Growth of TiO₂ in Interlayers of Expanded Graphite for the Fabrication of TiO₂–Graphene with Enhanced Photocatalytic Activity

Abstract

We present a facile route for the preparation of TiO(2)-graphene composites by in situ growth of TiO(2) in the interlayer of inexpensive expanded graphite (EG) under solvothermal conditions. A vacuum-assisted technique combined with the use of a surfactant (cetyltrimethylammonium bromide) plays a key role in the fabrication of such composites. Firstly, the vacuum environment promotes full infusion of the initial solution containing Ti(OBu)(4) and the surfactant into the interlayers of EG. Subsequently, numerous TiO(2) nanoparticles uniformly grow in situ in the interlayers with the help of the surfactant, which facilitates the exfoliation of EG under the solvothermal conditions in ethanol, eventually forming TiO(2)-graphene composites. The as-prepared samples have been characterized by Raman and FTIR spectroscopies, SEM, TEM, AFM, and thermogravimetic analysis. It is shown that a large number of TiO(2) nanoparticles homogeneously cover the surface of high-quality graphene sheets. The graphene exhibits a multi-layered structure (5-7 layers). Notably, the TiO(2)-graphene composite (only 30 wt % of which is TiO(2)) synthesized by subsequent thermal treatment at high temperature under nitrogen shows high photocatalytic activity in the degradation of phenol under visible and UV lights in comparison with bare Degussa P25. The enhanced photocatalytic performance is attributed to increased charge separation, improved light absorbance and light absorption width, and high adsorptivity for pollutants.

Facile and size-controllable preparation of graphene oxide nanosheets using high shear method and ultrasonic method

“…In the GO spectrum, a strong and broad band at 3410 cm ¡1 , which is due to the O-H stretching vibrations [47,48], and the presence of peaks between 1000 and 1750 cm ¡1 corresponding to a large number of functional groups. The bands at 1743 cm ¡1 [47,49,50] are related to the C=O stretching vibrations, the peak at 1637 cm ¡1 [50,51] is ascribed to C=C stretching vibration, and the bands at 869 [52], 1054 [52], 1230 [53] and 1400 cm ¡1 [54] are attributed to C-O stretching vibrations. No distinct differences are found between the spectrum of GO u4 and GO h4, indicating that the relative functional groups of GO nanosheets are similar and not affected by exfoliation method.…”

Fe 3 C@carbon nanocapsules/expanded graphite as anode materials for lithium ion batteries

“…Expanded graphite (EG), the most important graphite derivative, has aroused considerable interest [2][3][4][5][6]. Compared with graphite, EG exhibits much higher capacity owing to its larger pores, larger surface area, high conductivity, structural defects, chemical stability and extra space for lithium-ion storage.…”

Photochemical stability and reactivity of graphene oxide

“…Williams et al [8] synthesized a hybrid rGO-TiO 2 material by irradiating a suspension containing TiO 2 nanoparticles and GO. The use of rGO was proposed by several groups for the preparation of highly photoactive composite materials based on titanium dioxide for the catalytic oxidation of aqueous organic pollutants [9][10][11][12][13][14], in order to exploit the high charge mobility of graphene and to maximize the photocatalytic efficiency by hindering the process of charge recombination.…”