Oxygen-doped MoS 2 @In 2 S 3 /Bi 2 S 3 core-shell dual Z-scheme tandem heterojunctions are fabricated via two-step hydrothermal methods. In 2 S 3 and Bi 2 S 3 nanosheets grow on the outer surface of oxygen-doped MoS 2 spheres, and the tight interface between the spheres could ensure stable electron transfer. MoS 2 with oxygen defects could inhibit the recombination of photo-induced electron-hole pairs. The unique core-shell structure increases the interface area and provides adequate surface reactive sites for the reactants. The resultant MoS 2 @In 2 S 3 /Bi 2 S 3 shows broad-spectrum response and excellent photothermal effect, which is beneficial to trigger the near-field temperature rise and promote the photocatalytic process. The MoS 2 @In 2 S 3 /Bi 2 S 3 exhibits excellent photocatalytic H 2 evolution rate of 973.42 μmol h −1 g −1 , and the degradation efficiency of tetracycline within 90 min is 99.6%, which is ∼ 10 times higher than that of pristine MoS 2 . It can be ascribed to the unique core-shell dual Z-scheme tandem heterojunction structure facilitates the transfer and spatial separation of photogenerated electron-hole pairs, and greatly prolongs the carrier lifetime. In addition, the long-term stability indicates the potential applications due to the core-shell dual Z-scheme tandem structure inhibiting the photocorrosion of sulfides.
Wenqing Yu,Fanming Meng,Hainan Wei,Han Zhang,Sheng Yao
Designing heterogeneous photocatalysts to enhance the activity of photo-induced ch arge separation for efficient degradation of organic pollutants in aqueous systems remains a significant challenge. A double Z-scheme Ag 3 PO 4 /MOF-In 2 S 3 /Bi 2 S 3 heterojunction containing trace Ag compositing was rationally designed and prepared, and fully characterized. Nitrogen adsorption–desorption experiments and Ultraviolet–Visible diffuse reflection spectroscopy (UV–Vis DRS) showed that the heterostructure expanded the surface area of single component, and had the highest absorption rate and the widest range of light. The presence of Ag in this heterostructure was demonstrated by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS), which explained the strong resistance to photo corrosion and the highest current density exhibited by the composite in photocurrent response testing. The photocatalytic degradation of the antibiotic levofloxacin (LVX) was carried out, in which the degradation proportion of ABIS-Ⅲ sample was as high as 93.6 % within 90 min. Free radical scavenging assay and ESR experiment demonstrated that OH and O 2 – worked together to promote the degradation of LVX. Combined theoretical calculations with experimental results to reasonably construct a double Z-scheme to elaborate the carrier migration paths under light illumination. This novel double Z-scheme model heterojunction is expected to provide new ideas for the study of the photocatalytic mechanism of multiplicity complexes and the removal of antibiotic contaminants.
Mohammed A. Al-Tahan,Baoji Miao,Sankui Xu,Yange Cao,Mengyao Hou,Mohamed R. Shatat,Muhammad Asad,Yanwei Luo,Aml E. Shrshr,Jianmin Zhang
The specific energies and energy densities of lithium–sulfur (Li-S) batteries are influenced by various cell parameters, including the sulfur loading, the sulfur weight percentage in the cathode, and the electrolyte/sulfur ratio. An In 2 S 3 /Bi 2 S 3 @rGO heterostructure was obtained by growing indium sulfide nanoparticles on the surface of bismuth sulfide nanoflowers in a graphene oxide (GO) solution via a one-step solvothermal approach. This structure was introduced as a modified separator/dual-layer sulfur cathode for Li-S batteries. The Bi 2 S 3 /In 2 S 3 heterointerfaces act as active sites to speed up interfacial electron transfer, along with the entrapment, diffusion, and transformation of lithium polysulfides. A Li-S cell containing a dual-layer sulfur cathode (thin layer of In 2 S 3 /Bi 2 S 3 @rGO sandwiched between two thick layers of sulfur) and coupled with an In 2 S 3 /Bi 2 S 3 @rGO-coated separator suppressed the polysulfide shuttle effect. The cell based on the dual-layer sulfur cathode technology and operated at a current rate of 0.3C achieved a high capacity (7.1 mAh cm −2 ) after the 200th cycle, giving an electrolyte/sulfur ratio (10 µL mg −1 ) under a high sulfur loading (11.53 mg cm −2 ). These results demonstrate the unique nature of the dual-layer sulfur cathode technique, which can yield high energy density Li-S batteries with high sulfur loadings and low electrolyte/sulfur ratios.
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