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Z-scheme Bi2WO6/CuBi2O4 heterojunction mediated by interfacial electric field for efficient visible-light photocatalytic degradation of tetracycline
摘要： In order for the removal of Tetracycline (TC) in wastewaters, an efficient binary Bi2WO6/CuBi2O4 Z-scheme heterojunction photocatalyst was synthesized by loading Bi2WO6 (BWO) nanoparticles on CuBi2O4 (CBO) nanorods via a solvothermal route. The obtained Bi2WO6/CuBi2O4 composite displays photocatalytic activity for TC degradation more than five times higher than that for pure CBO nanorods. The recycling experiment shows that over 91% of TC can be photo-degraded by the optimal Bi2WO6/CuBi2O4 photocatalyst within 60 min even after four cycles. Results of SEM, transient photocurrent response, EIS measurement prove that solvothermal process for BWO loading can introduce rough surface with high-density negative charge on CBO, contributing to effective photo-induced carrier transfer. XPS, Mott?Schottky plots and PL spectra reveal that the loading of BWO as well as interfacial charge redistribution can induce the formation of interfacial electric field for Z-scheme heterojunction, contributing to the high oxidation and reduction capabilities ability of Bi2WO6/CuBi2O4 composite. The study on photocatalytic mechanism discloses that hole (h+) and superoxide radical (?O2?) are dominating reactive oxidation species (ROS) in the photodegradation process. This study has provided a novel route to fabricate Z-scheme photocatalysts for effective photocatalytic degradation processes.
关键词： charge transfer,Z-scheme heterojunction,environmental materials,interfacial electric field,photocatalysis,tetracycline degradation
更新于2025-11-21 10:59:37
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CuInS2 sensitized TiO2 for enhanced photodegradation and hydrogen production
摘要： A novel CuInS2/TiO2 (CIS-TO) heterojunction which displayed two different transfer pathways of photo-generated carries under UV–vis and Vis light irradiation was fabricated through a facile in-situ growth method. Under vis-light (λ ≥ 420 nm) excitation, 97.37% RhB (10 mg/L) was photodegraded with 20 mg of 1% CIS-TO photocatalyst within 90 min, and the degradation constant could up to 0.0415 min?1, which was about 8.28 times to pure TiO2 (0.00501 min?1) and the typical heterojunction was formed between CuInS2 and TiO2 to provide the photo-electrons transfer channel. Under UV–vis light irradiation, a Z-scheme heterojunction was formed to provide another highly effective electron transfer channel for hydrogen production and the hydrogen production rate could reach 785.4 μmol g?1 h?1 with 1% CIS-TO photocatalyst, which showed nearly 1.68 times than that of pure TiO2. The enhanced photocatalytic activity could be attributed to the synergistic effect of the sensitization and narrow band gap of CuInS2 which could effectively broaden the spectral response range, enhance the photon utilization and inhibit the recombination of photogenerated electrons and holes. Additionally, the high stability of the material was illustrated by the cycle experiments of photodegradation and hydrogen production.
关键词： Typical heterojunction,Sensitization,Z-scheme heterojunction,Photodegradation,CuInS2/TiO2
更新于2025-09-23 15:23:52
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A novel Z-scheme Ag3VO4/BiVO4 heterojunction photocatalyst: Study on the excellent photocatalytic performance and photocatalytic mechanism
摘要： A novel three-dimensional microspheres mediator-free Z-scheme Ag3VO4/BiVO4 heterojunction photocatalyst was successfully obtained for the first time. The photocatalytic performance of the as-prepared photocatalyst was systematically examined via the photocatalytic reduction of Cr6+ and oxidation of Bisphenol S under visible-light irradiation. Among these samples, 0.24-Ag3VO4/BiVO4 exhibits the highest photocatalytic performances, the photocatalytic reduction and oxidation efficiency of 74.9 and 94.8 %, respectively, can be achieved. The enhanced photocatalytic performance is attributed to the build-in electric field assisted charge transfer between the Ag3VO4 and BiVO4, and the increasing lifetime of the charge carrier confirmed by the results of time-resolved fluorescence spectra and photoelectrochemical measures. Moreover, based on the results of free radical scavenging activity test, and EPR experiments, it has been verified that the Ag3VO4/BiVO4 heterostructures follow a typical Z-scheme charge transfer mechanism rather than conventional type-II heterojunction charge transfer mechanism. Furthermore, the theoretical understanding of the underlying mechanism was also supported, while the energy band structure, and Fermi level were systematically calculated using the density functional theory approach. The results show that a built-in electric field directed from Ag3VO4 to BiVO4 surface was established as an equalized Fermi level was reached, which benefits the separation of photogenerated charge carriers in the way of a Z-scheme charge transfer mechanism. The strategy to form the three-dimensional microspheres Z-scheme heterojunction photocatalyst may offer new insight into the Z-scheme charge transfer mechanism for applications in the field of solar energy conversion.
关键词： Bismuth Vanadate,Z-scheme heterojunction photocatalyst,photocatalytic reduction and oxidation.
更新于2025-09-23 15:23:52
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Construction of Pt-decorated g-C3N4/Bi2WO6 Z-scheme composite with superior solar photocatalytic activity toward rhodamine B degradation
摘要： Highly efficient visible-light-driven Pt-decorated g-C3N4/Bi2WO6 hybrid photocatalysts were successfully prepared via a photodeposition method. The microstructures and optical properties of the prepared samples were characterized by transient photocurrent experiments, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis diffused reflectance spectra (DRS), photoluminescence (PL), electron spin resonance (ESR) spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. FESEM and TEM images show that metallic Pt particles disperse on the surface of g-C3N4/Bi2WO6 hybrid. Pt-decorated g-C3N4/Bi2WO6 compsites exhibited excellent DRS attribute to the surface plasmonic resonance (SPR) of Pt particles and g-C3N4/Bi2WO6. The PL results verified that the suitable band potential of g-C3N4 and Bi2WO6 for construction of Z-type photocatalytic system. In the photocatalytic experiment, results showed that Pt(1%)-g-C3N4/Bi2WO6 photocatalysts displayed higher photocatalytic activity than either pure g-C3N4 or Bi2WO6 for the degradation of Rhodamine B (RhB). Additionally, the free-radical trapping experiments and ESR disclose that the hole (h+), superoxide radical (·O2-) and hydroxyl radical (·OH) acted as reactive species. Based on above, a possible plasmonic Z-scheme mechanism for organics degradation over Pt-decorated g-C3N4/Bi2WO6 was proposed.
关键词： g-C3N4/Bi2WO6,Visible light irradiation,Z-scheme heterojunction,Pt-decorated
更新于2025-09-23 15:23:52
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Two-dimensional g-C3N4/TiO2 Nanocomposites as Vertical Z-scheme Heterojunction for Improved Photocatalytic Water Disinfection
摘要： Developing highly active photocatalysts towards effective microorganism inactivation is a green and energy-smart strategy in response to the growing demands to water quality under the background of the water crisis. Here, a vertical face-to-face heterojunction was fabricated by horizontally assembling TiO2 nanosheets with {001} facets exposed on graphitic carbon nitride (g-C3N4) sheets through a facile hydrothermal driving coupling. The vertical heterojunction could almost completely disinfect 103 CFU/mL E. coli within 30 min under solar light, which was more efficient than the physically mixed composite and pure g-C3N4 and TiO2. The two-dimensional (2D) morphology provides ample surface area in forming the vertical heterojunction and enables intimate contact which is advantageous to charge transfer between g-C3N4 and TiO2. A Z-scheme charge transportation mechanism is confirmed through band structure analysis and reactive species (RSs) probing and trapping experiments. In comparison with physically mixed composite and the single-phase counterparts, the nanocomposite based on Z-scheme electron transfer mode effectively prompts charge pair dissociation and subsequently encourages bacterial inactivation by boosting the generation of RSs. The constructing vertical Z-scheme heterojunction highlights the potential of 2D nanomaterials for accelerated water sterilization.
关键词： photocatalysis,Z-scheme heterojunction,vertical heterojunction,two-dimensional materials,water disinfection
更新于2025-09-23 15:21:21
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CdS quantum dots modified surface oxygen vacancy defect ZnO1-x-TiO2-x solid solution sphere as Z-Scheme heterojunctions for efficient visible light-driven photothermal-photocatalytic performance
摘要： CdS quantum dots (QDs) modified surface oxygen vacancy defect ZnO1-x-TiO2-x solid solution spheres were prepared by using a hydrothermal, chemical reduction and electroless plating strategy, which have sufficient negative conduction band potential while having a photoresponse in visible light region. According to the band energy alignment, Z-scheme structure is formed, which favors spatial charge separation. The obtained CdS QDs/ZnO1-x-TiO2-x heterojunctions with the gap of ~2.09 eV exhibit excellent photothermal performance and photocatalytic degradation of bisphenol A (~99.5%), 2,6-dichlorophenol (~99.1%), and 2,4,5-trichlorophenol (~98.9%). It can be attributed to the following reasons: (1) a solid solution strategy can be used to enhance the photocatalytic activity of a given semiconductor photocatalyst. (2) The presence of oxygen defects can extend the photoresponse to visible light region. (3) TiO2-x-ZnO1-x and CdS QDs can form Z-Scheme heterojunctions to increase the spatial separation of photogenerated electron-holes, which can promote photocatalytic performance. After recycle test, the resultant catalysts show high stability, which has superiority in practical application. So this novel CdS QDs modified surface oxygen vacancy defect ZnO1-x-TiO2-x solid solution sphere will have potential applications in environmental fields.
关键词： Photothermal-photocatalytic,Solid solution,Oxygen vacancy defect,Z-Scheme heterojunction,Quantum dot
更新于2025-09-23 15:19:57
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Platform for molecular-material dual regulation: A direct Z-scheme MOF/COF heterojunction with enhanced visible-light photocatalytic activity
摘要： Series of novel metal-organic framework/covalent organic framework (MOF/COF) hybrid materials were constructed by encapsulating MOF with highly stable TTB-TTA (a COF synthesized from 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (TTB) and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TTA)) layer, inheriting their merits of high crystallinity, large surface area, outstanding visible-light response and tunable band gaps. The introduction of NH2-MIL-125(Ti) into the hybrid materials could modulate their optical, electronic and redox properties, and promote the charge separation owing to the formation of heterojunction, thus resulting in an enhanced photocatalytic performance for organic pollutant decomposition. As such, NH2-MIL-125(Ti)/TTB-TTA composite has a much higher photodegradation kinetic of methyl orange (MO) which is over 9 and 2 times the rates of pure NH2-MIL-125(Ti) and TTB-TTA, respectively. This versatile molecular-material platform can achieve dual adjusting modes consisting of a COF molecular engineering and a MOF type screening strategy, which will be applicable to a wide range of fields.
关键词： metal-organic frameworks,covalent organic frameworks,heterogeneous photocatalysis,Z-scheme heterojunction,visible-light-driven
更新于2025-09-19 17:15:36
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Construction of Z-Scheme g-C3N4/CNT/Bi2Fe4O9 Composites with Improved Simulated-Sunlight Photocatalytic Activity for the Dye Degradation
摘要： In this work, ternary all-solid-state Z-scheme g-C3N4/carbon nanotubes/Bi2Fe4O9 (g-C3N4/CNT/BFO) composites with enhanced photocatalytic activity were prepared by a hydrothermal method. The morphology observation shows that ternary heterojunctions are formed in the g-C3N4/CNT/BFO composites. The photocatalytic activity of the samples for the degradation of acid orange 7 was investigated under simulated sunlight irradiation. It was found that the ternary composites exhibit remarkable enhanced photocatalytic activity when compared with bare BFO and g-C3N4/BFO composites. The effect of the CNT content on the photocatalytic performance of the ternary composites was investigated. The photocatalytic mechanism of g-C3N4/CNT/BFO was proposed according to the photoelectrochemical measurement, photoluminescence, active species trapping experiment and energy-band potential analysis. The results reveal that the introduction of CNT as an excellent solid electron mediator into the ternary composites can effectively accelerate the electron migration between BFO and g-C3N4. This charge transfer process results in highly-ef?cient separation of photogenerated charges, thus leading to greatly enhanced photocatalytic activity of g-C3N4/CNT/BFO composites. Furthermore, the g-C3N4/CNT/BFO composites also exhibit highly-ef?cient photo-Fenton-like catalysis property.
关键词： CNT,Bi2Fe4O9,photocatalysis,Z-scheme heterojunction,g-C3N4
更新于2025-09-10 09:29:36
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Enhanced visible light photoreduction of aqueous Cr(VI) by Ag/Bi4O7/g-C3N4 nanosheets ternary metal/non-metal Z-scheme heterojunction
摘要： In this paper, we successfully constructed a ternary metal/non-metal nanomaterial which can synergize Z-scheme heterojunction and plasmonic metal/semiconductor for enhancing visible light photoreduction of aqueous Cr(VI). The as-formed ternary metal/non-metal nanomaterial was composed of g-C3N4 nanosheets mutual modified by Ag nanoparticles and Bi4O7. In the ternary nanomaterial, g-C3N4 nanosheets and Bi4O7 fabricated Z-scheme heterojunction, g-C3N4 nanosheets and Ag nanoparticles formed plasmonic metal/semiconductor system, synchronously. The photodeposition experiments were designed to indirect demonstrate the Z-scheme heterojunction via photocatalytic oxidation and reduction deposition reactions, AgNO3 was used as the electron acceptor and Pb(NO3)2 as the electron donor, photocatalytic reduction product and oxidation product were selectively deposited on g-C3N4 nanosheets and Bi4O7, respectively, revealing the Z-scheme heterojunction was definite formed. In addition, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), UV–vis absorption, and Fourier-transform infrared spectroscopy (FTIR) were studied to indicate that the plasmonic metal/semiconductor system was existent in the ternary nanomaterial. The visible light photoreduction of ternary Ag/Bi4O7/g-C3N4 nanosheets was evaluated by photoreducing aqueous Cr(VI). The photoreduction results show that the ternary Ag/Bi4O7/g-C3N4 nanosheets is much higher than the pristine bulk g-C3N4 and g-C3N4 nanosheets.
关键词： Visible light,Z-scheme heterojunction,g-C3N4,Bi4O7,Cr(VI) reduction,Ag nanoparticles
更新于2025-09-10 09:29:36
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In situ synthesis of Z-scheme BiPO4/BiOCl0.9I0.1 heterostructure with multiple vacancies and valence for efficient photocatalytic degradation of organic pollutant
摘要： Design and construction of Z-scheme photocatalyst has been attracted much attention, which is a great challenge to develop highly efficient photocatalyst without the external redox mediators. Herein, a novel efficient redox-mediator-free Z-scheme BiPO4/BiOCl0.9I0.1 heterojunction is synthesized in situ via a mild 90℃ water bath reaction. The as-synthesized BiPO4/BiOCl0.9I0.1 heterostructure exhibits outstanding photocatalytic performance for degradation of phenol and Rhodamine B, approximately 2.6 and 4.3 times higher than that of BiOCl0.9I0.1, respectively. The BiPO4/BiOCl0.9I0.1 heterostructure have multiple vacancies and valence, such as Bi5+, Bi3+, Bi(3-x)+, I-, I3-, and IO3-, which could facilitate the charge separation and transfer in the photocatalytic process. The higher photocatalytic activity of redox-mediator-free Z-scheme BiPO4/BiOCl0.9I0.1 heterostructure could be attributed to the strong redox ability, multiple charge transfer channels via the various defects, and tight contact due to in situ synthesis. The finding provides some new insights for the design of effective direct Z-scheme photocatalyst with multiple defects.
关键词： direct Z-scheme heterojunction,photocatalysis,BiOCl0.9I0.1/BiPO4,redox-mediator-free,multiple defects
更新于2025-09-04 15:30:14