Multilayer core–shell MoS<sub>2</sub>/CdS nanorods with very high photocatalytic activity for hydrogen production under visible-light excitation and investigation of the photocatalytic mechanism by femtosecond transient absorption spectroscopy

Yan, Zhi‐Ping; Du, Lili; Phillips, David Lee

doi:10.1039/c7ra12118k

Cited by 46 publications

(27 citation statements)

References 45 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The conduction band edge of CdS is more negative than the reduction potential of H + /H 2 , making it more suitable for the H 2 generation 17,18 . There are reports on the synthesis of CdS/MoS 2 composites via various approaches, which shows the good photocatalytic activity as compared to pristine CdS 19 . However, there is still scope to improve photocatalytic activity of CdS toward water splitting by solving the photo corrosion and faster charge recombination problem 14,20 .…”

Section: Introductionmentioning

confidence: 99%

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Kadam

Gosavi

Kale

et al. 2019

Sci Rep

View full text Add to dashboard Cite

The hierarchical nanostructured CdS@MoS 2 core shell was architectured using template free facile solvothermal technique. More significantly, the typical hexagonal phase of core CdS and shell MoS 2 has been obtained. Optical study clearly shows the two steps absorption in the visible region having band gap of 2.4 eV for CdS and 1.77 eV for MoS 2 . The FESEM of CdS@MoS 2 reveals the formation of CdS microsphere (as a core) assemled with 40–50 nm nanoparticles and covered with ultrathin nanosheets of MoS 2 (Shell) having size 200–300 nm and the 10–20 nm in thickness. The overall size of the core shell structure is around 8 µm. Intially, there is a formation of CdS microsphre due to high affinity of Cd ions with sulfur and further growth of MoS 2 thin sheets on the surface. Considering band gap ideally in visible region, photocatalytic hydrogen evolution using CdS@MoS 2 core shell was investigated under natural sunlight. The utmost hydrogen evolution rate achieved for core shell is 416.4 µmole h −1 with apparent quantum yield 35.04%. The photocatalytic activity suggest that an intimate interface contact, extended visible light absorption and effective photo generated charge carrier separation contributed to the photocatalytic enhancement of the CdS@MoS 2 core shell. Additional, the enhanced hole trapping process and effective electrons transfer from CdS to MoS 2 in CdS@MoS 2 core shell heterostructures can significantly contribute for photocatalytic activity. Such core shell heterostructure will also have potential in thin film solar cell and other microelectronic devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Kadam

Gosavi

Kale

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The high-resolution XPS spectrum of Cd exhibited two different peaks at the binding energies of 405.4 and 412.1 eV (Fig. 5b), which correspond to Cd 3d 3/2 and Cd 3d 5/2 of Cd 2+ in CdS, respectively [50]. As shown in Fig.…”

Section: Characterizations Of the Cds@mos 2 Photocatalystmentioning

confidence: 90%

“…Moreover, the high-resolution XPS spectrum of S 2p showed two distinct peaks at binding energies of 161.6 and 162.9 eV (Fig. 5d), which are respectively assigned to the S 2p 3/2 and S 2p 1/2 in the form of S 2− in the CdS@MoS 2 composite [50].…”

Section: Characterizations Of the Cds@mos 2 Photocatalystmentioning

confidence: 97%

Visible-light-driven photocatalytic hydrogen production coupled with selective oxidation of benzyl alcohol over CdS@MoS2 heterostructures

Zhao

Yan

et al. 2020

Sci. China Mater.

View full text Add to dashboard Cite

Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention. Herein, we report a noble metal-free photocatalyst for the highly efficient and simultaneous generation of hydrogen and the selective oxidation of benzyl alcohol into benzaldehyde over CdS@MoS 2 heterostructures under visible light. Without the need for a sacrificial agent, CdS@MoS 2 displayed an excellent hydrogen production rate of 4233 μmol g −1 h −1 with 0.3 mmol benzyl alcohol, which is approximately 53 times higher than that of bare CdS nanorods (80 μmol g −1 h −1). The reaction system was highly selective for the oxidation of benzyl alcohol into benzaldehyde. When the amount of benzyl alcohol increased to 1.0 mmol, the hydrogen production reached 9033 μmol g −1 h −1. Scanning electron microscopy and transmission electron microscopy images revealed that p-type MoS 2 sheets with a flower-like structure closely adhered to n-type semiconductor CdS nanorods through the formation of a p-n heterojunction. As a potential Z-scheme photocatalyst, the CdS@MoS 2 heterostructure effectively produces and separates electron-hole pairs under visible light. Thus, the electrons are used for reduction to generate hydrogen, and the holes oxidize benzyl alcohol into benzaldehyde. Moreover, a mechanism of photogenerated charge transfer and separation was proposed and verified by photoluminescence, electrochemical impedance spectroscopy, photocurrent and Mott-Schottky measurements. The results reveal that the CdS@MoS 2 heterojunctions have rapid and efficient charge separation and transfer, thereby greatly improving benzyl alcohol dehy-drogenation. This work provides insight into the rational design of high-performance Z-scheme photocatalysts and the use of holes and electrons to obtain two valuable chemicals simultaneously.

show abstract

“…As a comparison, various inexpensive and earth‐abundant cocatalysts including sulfides (MoS 2 , Cu 2 S, and NiS 2 ) and phosphides (Ni 2 P and CoP) and carbon group (graphene, carbon nanotubes, and onion‐like carbon) are recently adopted in CdS or CdZnS‐based photocatalytic H 2 generation . Among them, MoS 2 nanosheets are extensively loaded onto CdS nanoparticles, nanorods, and nanowires to prompt carrier separation and hydrogen evolution . For example, hydrogen generation rates of 1.8 and 5.24 mmol/h/g were established by loading CdS onto MoS 2 /graphene nanosheets and loading MoS 2 flakes onto CdS nanoparticles, respectively .…”

Section: Introductionmentioning

confidence: 99%

Multifunctional MoS ₂ ultrathin nanoflakes loaded by Cd _0.5 Zn _0.5 S QDs for enhanced photocatalytic H ₂ production

et al. 2019

View full text Add to dashboard Cite

Summary Two‐dimensional MoS2 has been widely used as hydrogen evolution reaction (HER) cocatalyst to load onto nanostructured semiconductors for visible light‐response photocatalytic hydrogen production. However, its another important role as light harvester because of the band‐gap tunable property and beneficial band position has been rarely exploited. Herein, few layer‐thick MoS2 nanoflakes with extended light absorption over the range of 400 to 680 nm and a photocatalytic HER rate of 0.98 mmol/h/g have been obtained. Then 7‐nm‐sized Cd0.5Zn0.5S quantum dots (QDs) are selectively grown upon ultrathin MoS2 nanoflakes for enhanced photocatalytic H2 generation. Upon the photocatalytic, light absorption, and charge transfer properties of the MoS2‐Cd0.5Zn0.5S composites evolved with the amount of MoS2 from 0 to 3 wt%, the multiple roles of MoS2 as long‐wavelength light absorber, in‐plane carrier mediator, and edge site‐active HER catalyst have been revealed. An optimum H2 generation rate of 8863 μmol/h/g and a solar to hydrogen (STH) efficiency of 2.15% have been achieved for 2 wt% MoS2‐Cd0.5Zn0.5S flakes. Such a strategy can be applied to other cocatalysts with both the light response and HER activity for efficient photocatalytic property.

show abstract

Multilayer core–shell MoS₂/CdS nanorods with very high photocatalytic activity for hydrogen production under visible-light excitation and investigation of the photocatalytic mechanism by femtosecond transient absorption spectroscopy

Abstract: Understanding the structural features and the dynamics and properties of charge carriers in photocatalysts is critical to develop them for practical applications.

Cited by 46 publications

References 45 publications

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Visible-light-driven photocatalytic hydrogen production coupled with selective oxidation of benzyl alcohol over CdS@MoS2 heterostructures

Multifunctional MoS ₂ ultrathin nanoflakes loaded by Cd _0.5 Zn _0.5 S QDs for enhanced photocatalytic H ₂ production

Contact Info

Product

Resources

About

Multilayer core–shell MoS2/CdS nanorods with very high photocatalytic activity for hydrogen production under visible-light excitation and investigation of the photocatalytic mechanism by femtosecond transient absorption spectroscopy

Abstract: Understanding the structural features and the dynamics and properties of charge carriers in photocatalysts is critical to develop them for practical applications.

Cited by 46 publications

References 45 publications

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Unique CdS@MoS2 Core Shell Heterostructure for Efficient Hydrogen Generation Under Natural Sunlight

Visible-light-driven photocatalytic hydrogen production coupled with selective oxidation of benzyl alcohol over CdS@MoS2 heterostructures

Multifunctional MoS 2 ultrathin nanoflakes loaded by Cd 0.5 Zn 0.5 S QDs for enhanced photocatalytic H 2 production

Contact Info

Product

Resources

About

Multilayer core–shell MoS₂/CdS nanorods with very high photocatalytic activity for hydrogen production under visible-light excitation and investigation of the photocatalytic mechanism by femtosecond transient absorption spectroscopy

Multifunctional MoS ₂ ultrathin nanoflakes loaded by Cd _0.5 Zn _0.5 S QDs for enhanced photocatalytic H ₂ production