Synthesis of n -type TaON microspheres decorated by p -type Ag 2 O with enhanced visible light photocatalytic activity

Construction of the Photocatalytic Film of the Recyclable TaON/Nickel Foam with Ohmic Junction for Efficient Wastewater Treatment

A recyclable photocatalytic film of TaON/Ni foam with ohmic junction is prepared by the electrophoretic deposition technology. The photocatalytic film of 60 mg TaON/Ni foam demonstrates excellent photocatalytic activity and recycling performance for the degradation of basic fuchsin from water. Around 80% of basic fuchsin (50 mL, 10 mg L−1) is removed over 60 mg TaON/Ni foam under irradiation of 72 W LED white light for 5 h. The photocatalytic activity of the film does not significantly decrease after three rounds of use. The active species for the photocatalytic degradation of basic fuchsin are ·O2−, h+ and ·OH.

The Surface Modification of Ag3PO4 using Tetrachloroaurate(III) and Metallic Au for Enhanced Photocatalytic Activity

The improvement of Ag3PO4 photocatalytic activity was successful by incorporating tetrachloroaurate(III) (AuCl4−)  and metallic Au on the surface of Ag3PO4. The photocatalysts were synthesized using the coprecipitation and chemisorption method. Coprecipitation of Ag3PO4 was carried out under ethanol-water solution using the starting material of AgNO3 and Na2HPO4.12H2O. AuCl4− ion and metallic Au were incorporated on the surface of Ag3PO4 using a chemisorption method under auric acid solution. The photocatalysts were characterized using XRD, DRS, SEM, and XPS. The AuCl4− ion and metallic Au were simultaneously incorporated on the Ag3PO4 surface. The high photocatalytic activity might be caused by increasing the separation of hole and electron due to capturing photogenerated electrons by metallic Au and Au(III) as electron acceptors. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Facile fabrication of hierarchical p-Ag2O/n-Nb2O5 heterojunction microspheres with enhanced visible-light photocatalytic activity

Constructing p-n heterojunction is an efficient strategy to improve the photocatalytic efficiency. Here, we report a hierarchical Ag2O/Nb2O5 heterojunction composite as a novel and efficient visible-light driven photocatalyst. Hierarchical Nb2O5 microspheres were prepared by a hydrothermal method, and then the in situ growth of Ag2O nanoparticles on their surfaces was realized by a simple deposition method. Structural and textural features of the Ag2O/Nb2O5 composites were investigated, revealing that Ag2O nanoparticles were well distributed on the surface of Nb2O5 microspheres. Photocatalytic degradation of rhodamine B (RhB) was significantly enhanced by Ag2O/Nb2O5 photocatalysts under visible light. The optimal Ag/Nb molar ratio was determined to be 0.15 : 1, which yielded a 21.8 times faster degradation rate constant than plain Nb2O5 microspheres and had excellent stability for at least 4 catalytic cycles. The superior photocatalytic performance of Ag2O/Nb2O5 photocatalyst can be ascribed to the hierarchical superstructure as well as the heterojunction between Ag2O and Nb2O5, which facilitated the separation of photogenerated charge carriers. This work has potential application in the future for solving environmental pollution.

A novel 3D Z-scheme heterojunction photocatalyst: Ag6Si2O7 anchored on flower-like Bi2WO6 and its excellent photocatalytic performance for the degradation of toxic pharmaceutical antibiotics

A novel 3D Ag₆Si₂O₇/Bi₂WO₆ Z-scheme heterojunction exhibited excellent photocatalytic performance for the degradation of toxic pharmaceutical antibiotics.

Efficient visible-light-driven photocatalytic hydrogen production over a direct Z-scheme system of TaON/Cd0.5Zn0.5S with a NiS cocatalyst

In this work, a study on the photocatalytic evolution of H₂ showed that the direct Z-scheme T4-ZCS with 0.5 wt% NiS cocatalyst could reach the highest H₂ evolution rate of 34.8 mmol h⁻¹ g⁻¹ with a quantum yield of about 25.5%.

In situ construction of WO3 nanoparticles decorated Bi2MoO6 microspheres for boosting photocatalytic degradation of refractory pollutants

Visible-light-driven (VLD) heterojunction photocatalysts for refractory contaminant degradation have aroused huge interest because of their outstanding photocatalytic performance. From the aspect of practical application, it is important to develop a highly efficient, durable, eco-friendly and inexpensive VLD photocatalyst. Herein, we report a novel VLD WO₃/Bi₂MoO₆ heterojunction photocatalyst with remarkable photocatalytic activity, which was fabricated via an electrospinning-calcination-solvothermal route. The phase, composition, morphologies, and optical properties of WO₃/Bi₂MoO₆ heterojunctions were comprehensively characterized. The photocatalytic performance of WO₃/Bi₂MoO₆ heterojunctions was assessed by the removal of rhodamine (RhB) and tetracycline hydrochloride (TC) under visible light (VL). WO₃/Bi₂MoO₆ heterojunctions displayed superior photocatalytic activities compared to Bi₂MoO₆, WO₃, or the mechanical mixture of WO₃ and Bi₂MoO₆. In particular, the heterojunction material (0.4WB, theoretical molar ratio of WO₃/Bi₂MoO₆ is 0.4/1.0) exhibited the best degradation efficiency (100%) and mineralization rate (52.3%) in 90 min, both of which exceeded the observed rates for Bi₂MoO₆ by 5.3 and 6.4 times, respectively. Moreover, 0.4WB showed a good durability in eight runs. The optimized photocatalytic property of WO₃/Bi₂MoO₆ can be attributed to enhanced VL absorption and reduced recombination efficiency of carriers owing to the synergistic effects between Bi₂MoO₆ and WO₃. The necessity of direct contact between WO₃/Bi₂MoO₆ and contaminants was experimentally verified. The study on photocatalytic mechanism demonstrates that superoxide free radicals (O₂^-) and photo-generated hole (h⁺) are dominantly responsible for the pollutant degradation, as demonstrated by the trapping experiments and electron spin resonance (ESR) analysis. Therefore, the WO₃/Bi₂MoO₆ heterojunction holds huge potential to be utilized as a durable and highly active photocatalyst for wastewater treatment.

Facile Synthesis of Bi2MoO6 Microspheres Decorated by CdS Nanoparticles with Efficient Photocatalytic Removal of Levfloxacin Antibiotic

Developing high-efficiency and stable visible-light-driven (VLD) photocatalysts for removal of toxic antibiotics is still a huge challenge at present. Herein, a novel CdS/Bi2MoO6 heterojunction with CdS nanoparticles decorated Bi2MoO6 microspheres has been obtained by a simple solvothermal-precipitation-calcination method. 1.0CdS/Bi2MoO6 has stronger light absorption ability and highest photocatalytic activity with levofloxacin (LEV) degradation efficiency improving 6.2 or 12.6 times compared to pristine CdS or Bi2MoO6. CdS/Bi2MoO6 is very stable during cycling tests, and no appreciable activity decline and microstructural changes are observed. Results signify that the introduction of CdS could enhance the light absorption ability and dramatically boost the separation of charge carriers, leading to the excellent photocatalytic performance of the heterojunction. This work demonstrates that flower-like CdS/ Bi2MoO6 is an excellent photocatalyst for the efficient removal of the LEV antibiotic.

Hierarchical heterostructures of Bi2MoO6 microflowers decorated with Ag2CO3 nanoparticles for efficient visible-light-driven photocatalytic removal of toxic pollutants

Developing highly active and durable visible-light-driven photocatalysts for the degradation of toxic pollutants is of vital significance. Herein, Ag₂CO₃ nanoparticles were in situ formed on Bi₂MoO₆ microflowers to produce Ag₂CO₃/Bi₂MoO₆ heterostructures via a facile procedure. The morphologies, phases, chemical compositions, and optical properties of Ag₂CO₃/Bi₂MoO₆ were examined by multiple characterization techniques. The Ag₂CO₃/Bi₂MoO₆ heterostructures exhibited substantially improved performance in the removal of industrial dyes (rhodamine B (RhB), methyl orange (MO), and methyl blue (MB)), and the antibiotic tetracycline hydrochloride (TC), compared with bare Bi₂MoO₆ and Ag₂CO₃ under visible-light irradiation. The enhancement of activity was attributed to the high charge-separation capacity, which results from the matched band alignment of the two components. The cycling experiments showed a good durability of Ag₂CO₃/Bi₂MoO₆. Holes were found to be the dominant active species accounting for the pollutant degradation. This compound is a promising candidate for wastewater treatment.

Graphene Oxide/BiOCl Nanocomposite Films as Efficient Visible Light Photocatalysts

A novel graphene oxide/BiOCl (GO/BiOCl) nanocomposite film was prepared via a spread coating method. In visible-light photocatalytically degrading Rhodamine B (RhB) experiments, 2 wt% GO/BiOCl could degrade 99% of RhB within 1.5 h and the rate constant was 12.2 times higher than that of pure BiOCl. The degradation efficiency still kept at 80% even after 4 recycles, evidencing the relatively good recyclability. The enhancement was attributed to the improvement of visible light adsorption and charge separation. Holes and superoxide radicals· O2- played a major role as reactive species. The values of conduction band and valence band for GO and BiOCl were calculated and a new photocatalytic mechanism of GO/BiOCl nanocomposite was proposed.

Ag3VO4 Nanoparticles Decorated Bi2O2CO3 Micro-Flowers: An Efficient Visible-Light-Driven Photocatalyst for the Removal of Toxic Contaminants

Semiconductor-based photocatalysis is of great potential for tackling the environmental pollution. Herein, a novel hierarchical heterostructure of Bi₂O₂CO₃ micro-flowers in-situ decorated with Ag₃VO₄ nanoparticles was developed by a facile method. Various characterization techniques have been employed to study the physical and chemical property of the novel catalyst. The novel catalyst was utilized for the photocatalytic removal of industrial dyes (rhodamine B, methyl orange) and tetracycline antibiotic under visible-light irradiation. The results indicated that Ag₃VO₄/Bi₂O₂CO₃ heterojunctions showed a remarkably enhanced activity, significantly higher than those of bare Ag₃VO₄, Bi₂O₂CO₃, and the physical mixture of Ag₃VO₄ and Bi₂O₂CO₃ samples. This could be ascribed to an enhanced visible-light harvesting capacity and effective separation of charge carriers by virtue of the construction of hierarchical Ag₃VO₄/Bi₂O₂CO₃ heterojunction. Moreover, Ag₃VO₄/Bi₂O₂CO₃ also possesses an excellent cycling stability. The outstanding performance of Ag₃VO₄/Bi₂O₂CO₃ in removal of toxic pollutants indicates the potential of Ag₃VO₄/Bi₂O₂CO₃ in real environmental remediation. Highlights Novel architectures of Ag₃VO₄ nanoparticles modified Bi₂O₂CO₃ micro-flowers were constructed.Novel Ag₃VO₄/Bi₂O₂CO₃ exhibited excellent photocatalytic activity and stability.Ag₃VO₄/Bi₂O₂CO₃ heterojunctions significantly promote the charge separation.

Ag2WO4 nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

To develop efficient and stable visible-light-driven (VLD) photocatalysts for pollutant degradation, we synthesized novel heterojunction photocatalysts comprised of AgI nanoparticle-decorated Ag2WO4 nanorods via a facile method. Various characterization techniques, including XRD, SEM, TEM, EDX, and UV-vis DRS were used to investigate the morphology and optical properties of the as-prepared AgI/Ag2WO4 catalyst. With AgI acting as the cocatalyst, the resulting AgI/Ag2WO4 heterostructure shows excellent performance in degrading toxic, stable pollutants such as rhodamine B (RhB), methyl orange (MO) and para-chlorophenol (4-CP). The high performance is attributed to the enhanced visible-light absorption properties and the promoted separation efficiency of charge carriers through the formation of the heterojunction between AgI and Ag2WO4. Additionally, AgI/Ag2WO4 exhibits durable stability. The active species trapping experiment reveals that active species (O2•- and h+) dominantly contribute to RhB degradation. The AgI/Ag2WO4 heterojunction photocatalyst characterized in this work holds great potential for remedying environmental issues due to its simple preparation method and excellent photocatalytic performance.

Facile Preparation of Nano-Bi₂MoO₆/Diatomite Composite for Enhancing Photocatalytic Performance under Visible Light Irradiation

In this work, a new nano-Bi₂MoO₆/diatomite composite photocatalyst was successfully synthesized by a facile solvothermal method. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV-vis diffuse reflection spectroscopy (DRS) were employed to investigate the morphology, crystal structure, and optical properties. It was shown that nanometer-scaled Bi₂MoO₆ crystals were well-deposited on the surface of Bi₂MoO₆/diatomite. The photocatalytic activity of the obtained samples was evaluated by the degradation of rhodamine B (RhB) under the visible light (λ > 420 nm) irradiation. Moreover, trapping experiments were performed to investigate the possible photocatalytic reaction mechanism. The results showed that the nano-Bi₂MoO₆/diatomite composite with the mass ratio of Bi₂MoO₆ to diatomaceous earth of 70% exhibited the highest activity, and the RhB degradation efficiency reached 97.6% within 60 min. The main active species were revealed to be h⁺ and•O²⁻. As a photocatalytic reactor, its recycling performance showed a good stability and reusability. This new composite photocatalyst material holds great promise in the engineering field for the environmental remediation.

Ta3N5 nanoparticles/TiO2 hollow sphere (0D/3D) heterojunction: facile synthesis and enhanced photocatalytic activities of levofloxacin degradation and H2 evolution

A novel 0D/3D Ta₃N₅ nanoparticles/TiO₂ hollow sphere heterojunction with efficient solar-light-driven levofloxacin degradation and H₂ evolution is fabricated.

Synthesis of a BiOCl1−xBrx@AgBr heterostructure with enhanced photocatalytic activity under visible light

We present a facile approach to preparing a BiOCl_1−xBr_x@AgBr heterostructure using a two-step solvothermal method. Multiple characterisation techniques have been employed to investigate its morphology, structure, optical and electronic properties and photocatalytic performance. The photocatalytic activity of the BiOCl_1−xBr_x@AgBr heterostructure was sufficiently evaluated by adopting Reactive Blue KN-R as the target organic pollutant under visible light irradiation. The as-prepared BiOCl_1−xBr_x@AgBr exhibited much higher photocatalytic activity than BiOCl_1−xBr_x and BiOCl, which was ascribed to the movement of photogenerated electrons from AgBr to BiOCl_1−xBr_x, resulting in effective charge separation and transfer. Moreover, the modification of BiOCl_1−xBr_x with AgBr broadened the light absorption range, making the composite suitable for visible light excitation. The excellent photocatalytic performance provides potential opportunities to utilize BiOCl_1−xBr_x@AgBr for environmental purification and organic pollution treatment of water.

BiOCl_1−xBr_x nanosheets are covered by a thin layer of AgBr that forms BiOCl_1−xBr_x@AgBr heterostucture with high photocatalytic activity.