Designing rGO/MoS₂hybrid nanostructures for photocatalytic applications

Abstract

Graphene and its derivatives exhibit large surface area, being ideal templates to facilitate the nucleation, growth or interaction of a huge variety of structures. Among them, molybdenum disulphide, with its structural and morphological compatibility with graphene, can be a candidate for achieving an excellent integration, to make new hybrid nanocomposites with outstanding characteristics. Among the synthesis methods of graphene/MoS2 composites, the solution-phase exfoliation of a MoS2/graphite mixture, by means of ultrasound vibrations, shows significant advantages in terms of large amount production without altering the main properties of 2D nanomaterials. Moreover MoS2, having a strong absorption in the visible, has been exploited as a novel visible light-sensitive semiconductor photocatalysts. But, due to the quick recombination of photo-generated charge carriers, the photocatalytic efficiency of MoS2 has to be further improved. Graphene and graphene related materials, as excellent electron-acceptor/transport materials, have been applied to photocatalysis, because they are able to decrease the photo-generated electron-hole recombination, thus improving the light absorption. Therefore, MoS2 and graphite oxide (GO) have been simultaneously sonicated in an ethanol/water mixture and characterized from the structure, morphology and electronic properties point of view. The composite was thermal treated in such a way to reduce GO and the photocatalytic activity of the reduced GO/MoS2 has been investigated by means of UV-vis spectroscopy, following the degradation of methylene-blue (MB) under solar-like irradiation.

Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

“…The weak reflection at 3450 cm −1 shows -OH stretching due to the hydroxyl groups attached to graphene planes [17,28]. The FTIR spectrum of the TS:GD solution presents some additional peaks (Figure 2b).…”

“…Also, graphene-TiO 2 interfaces provide effective charge transfer junctions, which help the injection of electrons from TiO 2 to graphene sheets leading to prolonged recombination [7,[13][14][15][16]. Beside coordination with inorganic materials, graphene provides a strong chemical affinity with organic materials, in particular with the organic dyes [17]. Figure 1b illustrates the band gap alignment of graphene-TiO 2 hybrid thin films.…”

A magnetically separable plate-like cadmium titanate–copper ferrite nanocomposite with enhanced visible-light photocatalytic degradation performance for organic contaminants

“…To check the effectiveness of our photocatalyst, the degradation efficiency of the present work was compared with some of the earlier reported photocatalysts [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] and the results are presented in Table 2. It is clear that the earlier studies have utilized high power xenon and mercury lights for the degradation of low concentration of dyes (5-10 mg L À1 ) with more quantity of photocatalyst (50-300 mg) and longer times (100-300 min).…”

Molecules and heterostructures at TiO2 surface: the cases of H2O, CO2, and organic and inorganic sensitizers

“…Notice from UV-visible spectra (Fig. 13b, bottom panel on the left) the typical features of MoS2 particles at the 650 nm and 605 nm due to the A and B excitonic peaks ( [151] and ref. therein).…”