Novel magnetically separable ZnO/AgBr/Fe3O4/Ag3VO4 nanocomposites with tandem n–n heterojunctions as highly efficient visible-light-driven photocatalysts

Shekofteh-Gohari, Maryam; Habibi‐Yangjeh, Aziz

doi:10.1039/c5ra21356h

Cited by 98 publications

(17 citation statements)

References 46 publications

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“…Subsequently, the electrons transfer to the conduction band of ZnO where they react with adsorbed oxygen to form the radical species (superoxide and hydroxyl radicals). Accordingly, the holes are directly involved in the degradation of the pollutants since they are not positive enough to oxidise water for the hydroxyl radicals [141,142]. The electrons and holes occupied different sites in the nanocomposite photocatalysts, which ensured efficient charge separation and the formation of the reactive species for pollutant degradation.…”

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

“…Moreover, it was shown that despite the formation of the composite photocatalysts, the presence of Fe 3 O 4 nanoparticles ensured that the photocatalysts still retained sufficient magnetic response to allow for efficient separation using an external magnetic field. Obviously, the magnetisation saturation of Fe 3 O 4 decreased sharply upon the formation of the nanocomposites due to their interaction and coverage by the non-magnetic components of the photocatalysts [141][142][143][144][145] 4 , respectively, are excited, and electrons are promoted to the conduction band, while the holes remain in the valence band. Subsequently, the electrons transfer to the conduction band of ZnO where they react with adsorbed oxygen to form the radical species (superoxide and hydroxyl radicals).…”

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

“…Meanwhile, the SPR-generated holes in Ag could react with water to form the hydroxyl radicals and together with the superoxide radicals are responsible for pollutant degradation [139]. Yan et al photocatalysts [141][142][143][144][145]. Under visible light irradiation, ZnO remains inactive and only the cocatalyst with a narrow band gap can be excited.…”

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

“…Habibi-Yangjeh's group has recently prepared and investigated the visible light photocatalytic properties of various magnetic nanocomposites-based on Fe3O4 and ZnO such as ZnO/AgI/Fe3O4 [141], ZnO/AgBr/Fe3O4/Ag3VO4 [142], ZnO/Ag3VO4/Fe3O4 [143], Fe3O4/ZnO/AgCl [144], and Fe3O4/AgBr-ZnO [145] towards model pollutants such as RhB, phenol, MB, and MO. All of the nanocomposite photocatalysts showed good photocatalytic properties, which can be credited to efficient charge separation and improved visible light absorption as a result of the heterojunctions formed between ZnO and the co-catalysts.…”

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

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Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation

Mamba

Mishra

2016

Catalysts

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Organic and inorganic compounds utilised at different stages of various industrial processes are lost into effluent water and eventually find their way into fresh water sources where they cause devastating effects on the ecosystem due to their stability, toxicity, and non-biodegradable nature. Semiconductor photocatalysis has been highlighted as a promising technology for the treatment of water laden with organic, inorganic, and microbial pollutants. However, these semiconductor photocatalysts are applied in powdered form, which makes separation and recycling after treatment extremely difficult. This not only leads to loss of the photocatalyst but also to secondary pollution by the photocatalyst particles. The introduction of various magnetic nanoparticles such as magnetite, maghemite, ferrites, etc. into the photocatalyst matrix has recently become an area of intense research because it allows for the easy separation of the photocatalyst from the treated water using an external magnetic field. Herein, we discuss the recent developments in terms of synthesis and photocatalytic properties of magnetically separable nanocomposites towards water treatment. The influence of the magnetic nanoparticles in the optical properties, charge transfer mechanism, and overall photocatalytic activity is deliberated based on selected results. We conclude the review by providing summary remarks on the successes of magnetic photocatalysts and present some of the future challenges regarding the exploitation of these materials in water treatment.

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Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

Section: Magnetite (Fe 3 O 4 )-Based Magnetic Photocatalystsmentioning

confidence: 99%

See 2 more Smart Citations

Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation

Mamba

Mishra

2016

Catalysts

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“…As an n-type semiconductor (Maryam and Aziz 2016), ZnO has excellent optoelectrical behavior due to its natured wide band gap and large exciton binding energy. Nanoscale ZnO is a next-generation semiconductor material with potential applications in the catalytic and luminescent fields (Mishra et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ZnO with Enhanced Photocatalytic Activity: A Novel Approach Using Nanocellulose

et al. 2016

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*Well-crystallized and hexagonal wurtzite ZnO was synthesized with nanocellulose using a facile hydrothermal method. Many highly active (001) facets were retained in the obtained ZnO nanocrystals, presumably due to interaction between the polar facet of ZnO and the nanocellulose. Given its effective surface area, the synthesized ZnO exhibited good photocatalytic activity of degrading methylene blue. Its degradation efficiency reached 94.4% within 30 min (UV irradiation power of 6 W), which was 34% higher than that of Degussa TiO2 P25. The ZnO photocatalyst also exhibited excellent reusability, confirmed by no obvious abatement after its being re-used for 8 cycles. These ZnO nanomaterials were synthesized using renewable nanocellulose derived from cotton. This environmentally friendly and cost-effective approach is anticipated to be applied in the future synthesis of small-sized ZnO photocatalysts.

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A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

Huy

Thao

Dao

et al. 2017

Adv Materials Inter

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Photocatalysis involves the excitation of semiconductor materials by light absorption to produce electron-hole pairs, following charge-pair separation to induce the oxidation of organic pollutants. [1b] Among various semiconductors, oxides of the elements Ti, Bi, Zn, and Sn are preferable materials for photocatalytic processes. [1a] However, most of them generally show poor efficiency in photocatalytic reactivity due to wide band gaps of the materials and relatively high recombination rates of electron-hole pairs. Various promising approaches using composite materials, morphology control, noble metal loading, and heterostructural construction have been explored to enhance photocatalytic activity of the semiconductor materials. [1a] However, these strategies often require complicated preparation procedures. Therefore, the search for simple compounds with an enhanced ability to degrade organic pollutants has been the focus in photocatalytic research area. Recently, graphitic carbon nitride (g-C 3 N 4 ) with a stacked 2D structure has received much attention as a metal-free semiconductor and is rapidly becoming a favorite in material science. With medium band gap and thermal/chemical stability in an ambient environment, g-C 3 N 4 has become one of the most promising photocatalytic materials. [2] More importantly, doping with metal ions or nonmetal ions to form active sites for optimal heterojunctions leading to modify the band gap and morphology has been achieved for efficient separation of pairs electrons and holes to enhance the photocatalytic performance of g-C 3 N 4 significantly. A number of studies on the photocatalytic performance of g-C 3 N 4 have been reported to date. [3] Layered double hydroxides (LDHs), a group of layered functional materials with a special octahedral microstructure, have the following major features: the chemical composition of the layers is adjustable, the type and number of interlayer anions is exchangeable, and the particle size distribution is controllable. [4] Recently, LDHs have received worldwide attention because of their multiple applications, such as adsorbents, [5] catalysts, and catalytic supports. [6] The general formula of LDHs is [M 1−x 2+ M x 3+ (OH) 2 ] x+ (A n− ) x/n : yH 2 O, where M 2+ and M 3+ are divalent (Ca 2+ , Mg 2+ , Zn 2+ , Ni 2+ , Cu 2+ ) and trivalent (Al 3+ , Fe 3+ , Cr 3+ ) metal Novel photocatalysts in the form of zinc oxide-zinc bismuth oxide (mixedmetal oxide [MMO]) and graphitic carbon nitride (CN) hybrid composites are developed via a co-precipitation method followed by calcination at 520 °C. The as-prepared MMO-CN hybrid composites are evaluated on the basis of their photocatalytic activities for Rhodamine B (RhB) in aqueous solutions under visible light irradiation. The strong electronic coupling between two components within the MMO-CN heterostructure, which suppresses the photogenerated recombination of electrons and holes to a remarkable extent, is revealed. The prepared composites exhibit an excellent photocatalytic activity, leading to mo...

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Novel magnetically separable ZnO/AgBr/Fe₃O₄/Ag₃VO₄ nanocomposites with tandem n–n heterojunctions as highly efficient visible-light-driven photocatalysts

Abstract: In the present work, novel magnetically separable ZnO/AgBr/Fe3O4/Ag3VO4 nanocomposites with different weight percentages of Ag3VO4 were successfully prepared.

Cited by 98 publications

References 46 publications

Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation

Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation

Synthesis of ZnO with Enhanced Photocatalytic Activity: A Novel Approach Using Nanocellulose

A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

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