Facile Synthesis of Heterojunctioned ZnO/Bi2S3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation

Abstract

Heterojunctioned ZnO/Bi2S3 nanocomposites were prepared via a facile solvothermal method. The obtained photocatalysts were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoelectrochemical and Photoluminescence spectroscopy (PL), respectively. The results showed that ZnO/Bi2S3 composites exhibited the sandwiched-like structure, where ZnO nanoparticles were randomly embedded between Bi2S3 nanoflakes. The performance of photocatalytic Cr(VI) reduction under visible light indicated that ZnO/Bi2S3 composites exhibited high-efficiency photocatalytic activity in comparison with either Bi2S3 or ZnO. The 5%-ZnO/Bi2S3 photocatalyst removed 96% of Cr(VI) within 120 min at 20 mg/L initial concentration of Cr(VI). The enhanced performance of ZnO/Bi2S3 photocatalysts could be ascribed to the increased light harvesting and the effective separation and transfer of the photogenerated charge carriers across the heterojunction interface of the ZnO/Bi2S3 composite. This work could pave the way for the design of new hetero-structured materials and has great potential in environmental remediation.

Effect of heat treatment under vacuum on structure and visible-light photocatalytic activity of nano-TiO2

“…The decolorization efficiency was determined by the concentration of MO studied by the spectrophotometer (AOE, Shanghai, China) at the maximum absorption wavelength of 464 nm. [37][38][39] The degradation rate was calculated by the following formula: degradation rate (%) ¼ 100 Â (C 0 À C t )/C 0 . Where C 0 is the initial concentration of MO (mg L À1 ); C t is the concentration of MO in another given irradiation time (mg L À1 ).…”

Bioinspired ZnO-Based Solar Photocatalysts for the Efficient Decontamination of Persistent Organic Pollutants and Hexavalent Chromium in Wastewater

“…Although the micro/nanofern architecture of ZnO is very efficient in the absorption of light and pollutants, its low catalytic activity and low photocorrosion resistance under sunlight irradiation inhibit its use as a photocatalyst. Both photocatalytic performance and photocorrosion resistance under sunlight irradiation are conventionally improved by various surface modification or doping strategies [1,[21][22][23][24]. Photocatalytic reactions are largely superficial processes, and consequently, the adsorption and desorption kinetics and affinity are the determinants of photocatalytic performance.…”

“…It is well-known that for solar light-harvesting applications, the ZnO and ZnS bandgap can drastically be reduced by forming layered ZnO heterostructures. Similarly, the use of heterojunction structures such as ZnO/ZnS or ZnO/Bi2S3 is a promising strategy for improving the optoelectronic properties and photocorrosion resistance of ZnO photocatalysts for water decontamination [1,20,24]. As shown in Figure 3, the use of short sulfidation times (4 h) not only allowed the creation of a ZnO@ZnS core@shell structure without affecting the micro/nano-fern-shaped architecture (i.e., improved light trapping and pollutant adsorption), but it also allowed reduction of the bandgap of It is well-known that for solar light-harvesting applications, the ZnO and ZnS bandgap can drastically be reduced by forming layered ZnO heterostructures.…”

“…As shown in Figure 3, the use of short sulfidation times (4 h) not only allowed the creation of a ZnO@ZnS core@shell structure without affecting the micro/nano-fern-shaped architecture (i.e., improved light trapping and pollutant adsorption), but it also allowed reduction of the bandgap of It is well-known that for solar light-harvesting applications, the ZnO and ZnS bandgap can drastically be reduced by forming layered ZnO heterostructures. Similarly, the use of heterojunction structures such as ZnO/ZnS or ZnO/Bi 2 S 3 is a promising strategy for improving the optoelectronic properties and photocorrosion resistance of ZnO photocatalysts for water decontamination [1,20,24]. As shown in Figure 3, the use of short sulfidation times (4 h) not only allowed the creation of a ZnO@ZnS core@shell structure without affecting the micro/nano-fern-shaped architecture (i.e., improved light trapping and pollutant adsorption), but it also allowed reduction of the bandgap of ZnO micro/nanoferns (E g = 3.26 eV) to 2.88 eV (ZnO@ZnS(4 h) micro/nanoferns), thereby extending the photoresponse from UV to the visible domain.…”

Editorial: Special Issue on Photocatalytic Nanocomposite Materials (PNMs)

“…The "Facile Synthesis of Heterojunctioned ZnO/Bi 2 S 3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation" is reported by X. Yuan et al who showed that ZnO/Bi 2 S 3 composites exhibit a sandwich-like structure with the ZnO nanoparticles randomly embedded between Bi 2 S 3 nanoflakes [16]. The observed enhanced performance of the ZnO/Bi 2 S 3 photocatalysts is ascribed to an increased light harvesting performance and an effective separation and transfer of the photogenerated charge carriers across the heterojunction interface of the ZnO/Bi 2 S 3 composites.…”