Limits...
Superior adsorption and photoinduced carries transfer behaviors of dandelion-shaped Bi 2 S 3 @MoS 2 : experiments and theory

View Article: PubMed Central - PubMed

ABSTRACT

The enhanced light-harvesting capacity and effective separation of photogenerated carriers in fantastic hierarchical heterostructures enjoy striking attention for potential applications in the field of solar cells and photocatalysis. A three-dimensional (3D) dandelion-shaped hierarchical Bi2S3 microsphere compactly decorated with wing-shaped few layered MoS2 lamella (D-BM) was fabricated via a facile hydrothermal self-assembly process. Especially, polyethylene glycol (PEG) has been proven as the vital template to form D-BM microsphere. Importantly, the as-prepared D-BM microsphere presents pH-dependent superior adsorption behavior and remarkable visible light photocatalytic activity for degradation of organic dyestuffs (Rhodamine B/RhB and Methylene blue/MB), far exceeding those for the pure Bi2S3 and MoS2. It is understandable that D-BM with high surface area possesses more active sites and promotes light utilization due to the unique porous structure with outspread wings. Besides, based on the experiments and theoretical calculations, the staggered type II band alignment of D-BM permits the charge injection from Bi2S3 to MoS2, subsequently accelerates the separation and restrains the recombination of carriers, leading to excellent photocatalytic activity, as well as the photoconductance and photoresponse performance (with Ilight/Idark ratio 567).

No MeSH data available.


Calculated band structures (a,b), the density of states (c–e), and the crystal surface matching between the (130) and (001) crystal surfaces (f) of Bi2S3 and MoS2, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5304175&req=5

f10: Calculated band structures (a,b), the density of states (c–e), and the crystal surface matching between the (130) and (001) crystal surfaces (f) of Bi2S3 and MoS2, respectively.

Mentions: The obtained band structures and the density of states (DOS) of Bi2S3 and MoS2 have been shown in Fig. 10a–f, respectively. As we can see, the top of VB contains S 3p and few contributions of Bi 6s, while the bottom of CB are mostly Bi 6p and S 3p for Bi2S3, with calculated Eg = 1.44 eV. As for MoS2 (with calculated Eg = 1.29 eV), the top of VB originates from Mo 4d, and the bottom of CB are Mo 4d and some hybridization with S 3p. Note that Fig. 10f shows the crystal surface matching of MoS2 (top) and Bi2S3 (down). By aligning the Fermi level relative to the vacuum energy level, the obtained work functions for Bi2S3 and MoS2 are 4.88 and 5.00 eV, respectively. Due to the differential work functions, a built-in electric field from Bi2S3 to MoS2 can be established near the interface. Thus the built-in electric field of the composites is expected to facilitate the separation of photo-generated carriers. It can be concluded that the theoretical calculations of the band energy positions (Fig. 10e) keep highly unanimous with the experimental results. In consequence, the MoS2 nanosheets uniformly layered-coated the Bi2S3 microspheres sufficiently absorb visible-light and retard the electron-hole recombination, eventually leading to improvement of the photocatalytic and optoelectronic properties. Moreover, the unique novel architecture can provide valuable references to take advantage of solar energy in the future.


Superior adsorption and photoinduced carries transfer behaviors of dandelion-shaped Bi 2 S 3 @MoS 2 : experiments and theory
Calculated band structures (a,b), the density of states (c–e), and the crystal surface matching between the (130) and (001) crystal surfaces (f) of Bi2S3 and MoS2, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5304175&req=5

f10: Calculated band structures (a,b), the density of states (c–e), and the crystal surface matching between the (130) and (001) crystal surfaces (f) of Bi2S3 and MoS2, respectively.
Mentions: The obtained band structures and the density of states (DOS) of Bi2S3 and MoS2 have been shown in Fig. 10a–f, respectively. As we can see, the top of VB contains S 3p and few contributions of Bi 6s, while the bottom of CB are mostly Bi 6p and S 3p for Bi2S3, with calculated Eg = 1.44 eV. As for MoS2 (with calculated Eg = 1.29 eV), the top of VB originates from Mo 4d, and the bottom of CB are Mo 4d and some hybridization with S 3p. Note that Fig. 10f shows the crystal surface matching of MoS2 (top) and Bi2S3 (down). By aligning the Fermi level relative to the vacuum energy level, the obtained work functions for Bi2S3 and MoS2 are 4.88 and 5.00 eV, respectively. Due to the differential work functions, a built-in electric field from Bi2S3 to MoS2 can be established near the interface. Thus the built-in electric field of the composites is expected to facilitate the separation of photo-generated carriers. It can be concluded that the theoretical calculations of the band energy positions (Fig. 10e) keep highly unanimous with the experimental results. In consequence, the MoS2 nanosheets uniformly layered-coated the Bi2S3 microspheres sufficiently absorb visible-light and retard the electron-hole recombination, eventually leading to improvement of the photocatalytic and optoelectronic properties. Moreover, the unique novel architecture can provide valuable references to take advantage of solar energy in the future.

View Article: PubMed Central - PubMed

ABSTRACT

The enhanced light-harvesting capacity and effective separation of photogenerated carriers in fantastic hierarchical heterostructures enjoy striking attention for potential applications in the field of solar cells and photocatalysis. A three-dimensional (3D) dandelion-shaped hierarchical Bi2S3 microsphere compactly decorated with wing-shaped few layered MoS2 lamella (D-BM) was fabricated via a facile hydrothermal self-assembly process. Especially, polyethylene glycol (PEG) has been proven as the vital template to form D-BM microsphere. Importantly, the as-prepared D-BM microsphere presents pH-dependent superior adsorption behavior and remarkable visible light photocatalytic activity for degradation of organic dyestuffs (Rhodamine B/RhB and Methylene blue/MB), far exceeding those for the pure Bi2S3 and MoS2. It is understandable that D-BM with high surface area possesses more active sites and promotes light utilization due to the unique porous structure with outspread wings. Besides, based on the experiments and theoretical calculations, the staggered type II band alignment of D-BM permits the charge injection from Bi2S3 to MoS2, subsequently accelerates the separation and restrains the recombination of carriers, leading to excellent photocatalytic activity, as well as the photoconductance and photoresponse performance (with Ilight/Idark ratio 567).

No MeSH data available.