Investigating Visible-Photocatalytic Activity of MoS₂/TiO₂ Heterostructure Thin Films at Various MoS₂ Deposition Times

Abstract

MoS 2 /TiO 2 heterostructure thin films were fabricated by sol-gel and chemical bath deposition methods. Crystal structure, surface morphology, chemical states of all elements, and optical property of the obtained thin films were characterized by using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy techniques, respectively. Photocatalytic activity of all thin films was evaluated by measuring decomposition rate of methylene blue solution under visible light irradiation. The results indicate that ultrathin MoS 2 film on TiO 2 -glass substrate improves photocatalytic activity of TiO 2 in the visible light due to the efficient absorption of visible photon of MoS 2 few layers and the transfer of electrons from MoS 2 to TiO 2 . All MoS 2 /TiO 2 heterostructure thin films exhibit higher visible light photocatalytic activity than that of pure MoS 2 and TiO 2 counterparts. The best MoS 2 /TiO 2 heterostructure thin film at MoS 2 layer deposition time of 45 minutes can decompose about 60% MB solution after 150 minutes under visible light irradiation. The mechanism of the enhancement for visible-photocatalytic activity of MoS 2 /TiO 2 heterostructure thin film was also discussed.

Prepare heterostructure of MoS2/TiO2 solar cell via simple two-steps by hydrothermal method

“…37-1492). The strong intensity of the (002) diffraction peak in the sample XRD pattern suggests the formation of a stacked layered structure of MoS 2 [23]. Fig.…”

Visible-Light Active Titanium Dioxide Nanomaterials with Bactericidal Properties

“…Titania can be coupled with metal oxides (e.g., Cu 2 O, Fe 2 O 3 , WO 3 ) and chalcogenides (e.g., CdS, MoS 2 and WS 2 ) to form a heterojunction for the charge separation in enhanced visible light absorption. Those coupled semiconductors acting as sensitizers should be nontoxic, and exhibit visible light photocatalytic activity, with a bandgap smaller than that of titania [177][178][179][180][181][182][183]. In this respect, photoexcited electrons in the CB and holes in the VB of a sensitizer semiconductor can be transferred to the CB and VB of TiO 2 NPs [180].…”

“…Cadmium sulfide is toxic and carcinogenic, so it is unfavorable to form CdS/TiO 2 heterojunction for practical applications. Nontoxic molybdenum disulfide (MoS 2 ) with a direct band-gap of 1.9 eV can be coupled with titania to form MoS 2 /TiO 2 nanocomposites, having excellent visible photocatalytic activity [181] [177,179,182,183]. Inexpensive and nontoxic Cu 2 O, with its efficient electron injection to the conduction band of TiO 2 , is particularly suitable for forming heterojunction photocatalysts [182,183].…”

Recent Progress in Antimicrobial Nanomaterials

“…Cadmium sulfide is toxic and carcinogenic, so it is unfavorable to form CdS/TiO 2 heterojunction for practical applications. Nontoxic molybdenum disulfide (MoS 2 ) with a direct band-gap of 1.9 eV can be coupled with titania to form MoS 2 /TiO 2 nanocomposites, having excellent visible photocatalytic activity [181]. Oxide semiconductors, such as α-Fe 2 O 3 and Cu 2 O with a respective small bandgap of 2.2 eV and 2.17 eV, can also form composite photocatalysts, with TiO 2 having good antibacterial properties under visible light [177,179,182,183].…”