Preparation of titanium dioxide/tungsten disulfide composite photocatalysts with enhanced photocatalytic activity under visible light

Abstract

Titanium dioxide/tungsten disulfide (TiO 2 /WS 2 ) composite photocatalysts were fabricated via a one-step hydrothermal synthesis process, using TiCl 4 as titanium source and bulk WS 2 as sensitizer. The morphology, structure, specific surface area and optical absorption properties of the composite photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), specific surface area analyzer and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), respectively. The photocatalytic activity of as-prepared photocatalysts was evaluated by the degradation of methyl orange (MO) under illumination of 500 W Xenon lamp. The results indicated that TiO 2 /WS 2 composite photocatalysts possessed excellent photocatalytic activity, and ~95% of the degradation rate for MO was reached when molar ratio of WS 2 to TiO 2 was 0.004 and the irradiation time was 60 min. Moreover, the carrier trapping experiment and fluorescence spectra showed that •O 2 − was the key component in the photocatalytic degradation process and O 2 was reduced to be •O 2 − by the electrons from the conduction band of TiO 2 and WS 2 for the degradation of MO.

SnS2/TiO2 Nanocomposites for Hydrogen Production and Photodegradation under Extended Solar Irradiation

“…Recently, transition metal chalcogenides (TMCs) have gained more attention due to their electrocatalytic properties that includes indirect bandgaps, optoelectronic behavior, and their stability [16,17]. Moreover, the stronger edge effects and the quantum confinement effects make these nanodots (quantum dots) or nanostructures of metal chalcogenides possible to utilize considerable amounts of solar irradiation [17][18][19]. These are playing an increasingly important role in different applications, such as photo degradation [20], capacitors [21], and hydrogen evolution [22] due to their suitable electronic and optical properties.…”

CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation

“…In this regard, TMCs have gained much attention among the research community in the field of lithium ion batteries, solar cells and hydrogen evolution, due to their significant characteristic features that include indirect bandgaps, optoelectronic properties and stability [24]. In addition, nanodots (quantum dots)/nano structures of these metal chalcogenides show stronger edge effects, and the quantum confinement effect make them suitable to be utilized under solar simulated irradiation [24,25]. The transition metal chalcogenides can be synthesized by employing different techniques, such as one-pot wet chemical method [10], impregnation–sulfidation [11], simple microwave-assisted solvothermal process [26], ion exchange and precipitation methods [27], and hydrothermal method [28].…”

Zinc oxide/graphene‐like tungsten disulphide nanosheet photocatalysts: Synthesis and enhanced photocatalytic activity under visible‐light irradiation

“…However, photo‐induced electrons cannot effectively transfer to ZnO because the conduction band edge of graphene‐like WS 2 is lower than that of ZnO. Luckily, the quantum confinement effects make it possible to increase the band gap of the WS 2 nanosheet significantly, which could achieve the migration of electrons from the conduction band of WS 2 to that of ZnO . Therefore, the WS 2 nanosheet could be considered as an effective sensitizer to decorate ZnO.…”