Facile synthesis of flower-like Ag3VO4/Bi2WO6 heterojunction with enhanced visible-light photocatalytic activity
01 Sep 2017-Vol. 501, pp 156-163
TL;DR: It is found that the introduction of Ag3VO4 is in favor of suppressing the electron-hole pair recombination of Bi2WO6, leading to an enhanced photocatalytic activity with good stability and great potential in applications for environmental remediation.
Abstract: Constructing novel semiconductor heterojunctions is one of the most significant approaches to improving the photocatalytic performance of a photocatalyst. Herein, the Ag3VO4/Bi2WO6 heterojunction was prepared through in-situ anchoring Ag3VO4 nanoparticles (size: ∼21 nm) on the surface of Bi2WO6 microflowers (diameter: 2.5–4.5 μm) by a facile deposition route. The photocatalytic activity of these heterojunctions were studied by decomposing cationic dye rhodamine B (RhB), anionic dye methyl orange (MO) and neutral para-chlorophenol (4-CP) under visible light irradiation (λ > 400 nm). Among all the tested catalysts, the heterojunction with a Ag3VO4/Bi2WO6 molar ratio of 0.15/1 displays the maximum activity with the RhB degradation rate constant of up to 0.0392 min−1, a 6.7 or 1.7 times more enhancement compared with the pure Bi2WO6 or Ag3VO4. It is found that the introduction of Ag3VO4 is in favor of suppressing the electron-hole pair recombination of Bi2WO6, leading to an enhanced photocatalytic activity with good stability. The photogenerated holes (h+) and superoxide radicals ( O 2 - ) play critical roles during the photocatalytic process. Ag3VO4/Bi2WO6 will have great potential in applications for environmental remediation due to the facile preparation method and superior photocatalytic activity.
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TL;DR: A Z-scheme heterojunction of 2D/2D BP/monolayer Bi2 WO6 (MBWO) is fabricated by a simple and effective method, which broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
Abstract: Black phosphorus (BP), a star-shaped two-dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Now, a Z-scheme heterojunction of 2D/2D BP/monolayer Bi2 WO6 (MBWO) is fabricated by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g-1 , is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67 %. A Z-scheme photocatalytic mechanism is proposed based on monitoring of . O2 - , . OH, NO2 , and NO3 - species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
408 citations
TL;DR: In this article, major semiconductor photocatalytic materials, namely, TiO2, ZnO, WO3, SiC, CuO, CdS, PbS, and SnO2 are elaborately discussed.
278 citations
TL;DR: This review aims to clarify the corresponding issues through surveying literature, including the uncertainty about the identity of radicals in the bulk solution or adsorbed on the catalyst surface in quenching tests, selection of proper scavengers, and the incorrect identification of EPR signals.
221 citations
TL;DR: The study on photocatalytic mechanism demonstrates that superoxide free radicals and photo-generated hole (h+) are dominantly responsible for the pollutant degradation, as demonstrated by the trapping experiments and electron spin resonance (ESR) analysis.
219 citations
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TL;DR: In this tutorial review, the unique mechanistic characteristics, the constitution of photodegradation systems and their performance are described and the involved radical reactions during the degradation are discussed.
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TL;DR: It is demonstrated that efficient fixation of N2 to NH3 can proceed under room temperature and atmospheric pressure in water using visible light illuminated BiOBr nanosheets of oxygen vacancies in the absence of any organic scavengers and precious-metal cocatalysts.
Abstract: Even though the well-established Haber–Bosch process has been the major artificial way to “fertilize” the earth, its energy-intensive nature has been motivating people to learn from nitrogenase, which can fix atmospheric N2 to NH3 in vivo under mild conditions with its precisely arranged proteins Here we demonstrate that efficient fixation of N2 to NH3 can proceed under room temperature and atmospheric pressure in water using visible light illuminated BiOBr nanosheets of oxygen vacancies in the absence of any organic scavengers and precious-metal cocatalysts The designed catalytic oxygen vacancies of BiOBr nanosheets on the exposed {001} facets, with the availability of localized electrons for π-back-donation, have the ability to activate the adsorbed N2, which can thus be efficiently reduced to NH3 by the interfacial electrons transferred from the excited BiOBr nanosheets This study might open up a new vista to fix atmospheric N2 to NH3 through the less energy-demanding photochemical process
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TL;DR: Recent advances and emerging strategies in tailoring BiOX (X = Cl, Br, I) nanostructures to boost their photocatalytic properties are surveyed.
Abstract: Heterogeneous photocatalysis that employs photo-excited semiconductor materials to reduce water and oxidize toxic pollutants upon solar light irradiation holds great prospects for renewable energy substitutes and environmental protection. To utilize solar light effectively, the quest for highly active photocatalysts working under visible light has always been the research focus. Layered BiOX (X = Cl, Br, I) are a kind of newly exploited efficient photocatalysts, and their light response can be tuned from UV to visible light range. The properties of semiconductors are dependent on their morphologies and compositions as well as structures, and this also offers the guidelines for design of highly-efficient photocatalysts. In this review, recent advances and emerging strategies in tailoring BiOX (X = Cl, Br, I) nanostructures to boost their photocatalytic properties are surveyed.
952 citations
TL;DR: In this paper, the state-of-the-art progress of semiconductor/semiconductor heterostructured photocatalysts with diverse models, including type-I and type-II heterojunctions, Z-scheme system, p-n heterojunction, and homojunction band alignments, were explored for effective improvement of photocatalysis activity through increase of the visible-light absorption, promotion of separation, and transportation of the photoinduced charge carries.
Abstract: Semiconductor photocatalysts have received much attention in recent years due to their great potentials for the development of renewable energy technologies, as well as for environmental protection and remediation. The effective harvesting of solar energy and suppression of charge carrier recombination are two key aspects in photocatalysis. The formation of heterostructured photocatalysts is a promising strategy to improve photocatalytic activity, which is superior to that of their single component photocatalysts. This Feature Article concisely summarizes and highlights the state-of-the-art progress of semiconductor/semiconductor heterostructured photocatalysts with diverse models, including type-I and type-II heterojunctions, Z-scheme system, p–n heterojunctions, and homojunction band alignments, which were explored for effective improvement of photocatalytic activity through increase of the visible-light absorption, promotion of separation, and transportation of the photoinduced charge carries, and enhancement of the photocatalytic stability.
680 citations