MoS₂ quantum dots@TiO₂ nanotube composites with enhanced photoexcited charge separation and high-efficiency visible-light driven photocatalysis

Abstract

MoS quantum dots (QDs) that are 5 nm in size were deposited on the surface of ultrathin TiO nanotubes (TNTs) with 5 nm wall thickness by using an improved hydrothermal method to form a MoS QDs@TNT visible-light photocatalyst. The ultrathin TNTs with high percentage of photocatalytic reactive facets were fabricated by the commercially available TiO nanoparticles (P25) through an improved hydrothermal method, and the MoS QDs were acquired by using a surfactant-assisted technique. The novel MoS QDs@TNT photocatalysts showed excellent photocatalytic activity with a decolorization rate of 92% or approximately 3.5 times more than that of pure TNTs for the high initial concentration of methylene blue solution (20 mg l) within 40 min under visible-light irradiation. MoS as the co-catalysts favored the broadening of TNTs into the visible-light absorption scope. The quantum confinement and edge effects of the MoS QDs and the heterojunction formed between the MoS QDs and TNTs efficiently extended the lifetime of photoinduced charges, impeded the recombination of photoexcited electron-hole pairs, and improved the visible-light-driven high-efficiency photocatalysis.

Revealing the role of the 1T phase on the adsorption of organic dyes on MoS2 nanosheets

“…The high adsorption capacity reported for some MoS 2 nanosheets and MoS 2 based heterostructures were ascribed to the high surface area of MoS 2 and MoS 2 -composites, which increases the number of active sites per unit volume and consequently leads to high adsorption capacity. 31 However, in other studies, 7,32 it has been demonstrated that the surface area has no effect on the adsorption activity. Whereas an effect of intermolecular interaction, such as van der Waals and electrostatic attraction, 7 or the existence of highly reactive OH radical groups on the MoS 2 surface 33 was proposed.…”

Insights into the TiO2-Based Photocatalytic Systems and Their Mechanisms

“…Among the listed 2D TMC materials, the MoS 2 /TiO 2 system has been largely explored for the photocatalytic applications [192][193][194][195][196][197]. Interestingly, the charge transfer in this system depends upon the photon energy used to excite the system.…”

Hydrothermal synthesis of MoS2 nanosheet loaded TiO2 nanoarrays for enhanced visible light photocatalytic applications

“…20 It can be seen from the Raman curve of bare TiO 2 NRAs that the two resonance peaks centered at 445 and 608 cm À1 can be attributed to the B 1g and E g of TiO 2 with rutile phase, respectively. 21 There are three resonance peaks centered at 404, 445 and 608 cm À1 , which can be observed from MoS 2 -200/TiO 2 , which may be attributed to the out-of-plane E 2g 1 of MoS 2 and the B 1g and E g of TiO 2 , respectively. 22 These results indicate that a spot of MoS 2 nanosheets deposited on the TiO 2 NRAs.…”