- 标题
- 摘要
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- 实验方案
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Mesoporous g-C3N4 ultrathin nanosheets coupled with QDs self-decorated SnIn4S8 homojunctions towards highly efficient photocatalytic functional transformation
摘要： In this research, we rationally designed and synthesized quantum dots self-decorated SnIn4S8/g-C3N4 (QDs-SISCN) nanocomposites by in situ anchoring quantum dot (QDs) self-decorated SnIn4S8 (SIS) nanosheets onto the surface of mesoporous graphite carbon nitride (CN) nanosheets in a mixed solvothermal environment. The photoreduction of 4-nitroaniline (4-NA) was used to assess their photocatalytic activity. In this framework, the construction of CN nanosheets-supported QDs-decorated SIS homojunctions can integrate the advantages of both homojunctions and heterojunctions. Benefiting from those favourable properties, the QDs-SISCN nanocomposites exhibit superior photocatalytic activity towards 4-NA reduction under visible-light irradiation (l > 400) as a result of the optimizied amount of CN nanosheets added. The recycling experiments also reveal high stability of the QDs-SISCN nanocomposites during photocatalytic reactions for 4-NA reduction. Moreover, the investigation of the photocatalytic mechanism from systematic characterizations, including measurements of the photocurrent response, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) indicate that the improved separation efficiency of charge carriers is a critical parameter for the enhanced photocatalytic activity for 4-NA reduction. We expect this research to provide a promising path to the design and synthesis of highly efficient hybrid photocatalysts for functional-group transformations.
关键词： Photocatalyst,SnIn4S8,g-C3N4,Quantum dots
更新于2025-09-12 10:27:22
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A Facile Photocontrolled Iodine‐Mediated Reversible‐Deactivation Radical Polymerization System: Solution Polymerization of Methacrylates under Irradiation with NIR LED Light
摘要： Herein, near-infrared (NIR) photocontrolled iodine-mediated reversible-deactivation radical polymerization (RDRP) of various methacrylates without external photocatalyst was developed using alkyl iodide (e.g., 2-iodo-2-methylpropionitrile, CP-I) as the initiator at room temperature. We report the first example of using a series of special solvents containing carbonyl groups (e.g., 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), tetramethylurea (TMU), 1,3-dimethyl-tetrahydropyrimidin-2(1H)-one (DMPU), and N-methyl pyrrolidone (NMP)) as both solvent and catalyst for photocontrolled RDRP under irradiation with a long wavelength (λmax = 730 nm) light-emitting diode (LED) light. Therefore, the NIR photocontrolled polymerization system has the simplest components: monomer, alkyl iodide initiator and solvent. Well-defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn < 1.21). The “living” features of this promising NIR photocontrolled iodine-mediated RDRP system were confirmed by polymerization kinetics, multiple controlled “on-off” light switching cycle regulation, and chain extension experiments. Importantly, the radical polymerizations were also proceeded successfully with various thickness of skin of pork and A4 paper to demonstrate the unique advantages of this simplest polymerization system, which benefitting from the high penetration of NIR light.
关键词： radical polymerization,photopolymerization,alkyl iodide,NIR light,photocatalyst-free
更新于2025-09-12 10:27:22
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A Facile Photocontrolled Iodine-Mediated Reversible-Deactivation Radical Polymerization System: Solution Polymerization of Methacrylates under Irradiation with NIR LED Light
摘要： Herein, near-infrared (NIR) photocontrolled iodine-mediated reversible-deactivation radical polymerization (RDRP) of various methacrylates without external photocatalyst was developed using alkyl iodide (e.g., 2-iodo-2-methylpropionitrile, CP-I) as the initiator at room temperature. We report the first example of using a series of special solvents containing carbonyl groups (e.g., 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), tetramethylurea (TMU), 1,3-dimethyl-tetrahydropyrimidin-2(1H)-one (DMPU), and N-methyl pyrrolidone (NMP)) as both solvent and catalyst for photocontrolled RDRP under irradiation with a long wavelength (λmax = 730 nm) light-emitting diode (LED) light. Therefore, the NIR photocontrolled polymerization system has the simplest components: monomer, alkyl iodide initiator and solvent. Well-defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn < 1.21). The “living” features of this promising NIR photocontrolled iodine-mediated RDRP system were confirmed by polymerization kinetics, multiple controlled “on-off” light switching cycle regulation, and chain extension experiments. Importantly, the radical polymerization were also proceeded successfully with various thickness of skin of pork and A4 paper to demonstrate the unique advantages of this simplest polymerization system, which benefitting from the high penetration of NIR light.
关键词： radical polymerization,photopolymerization,alkyl iodide,NIR light,photocatalyst-free
更新于2025-09-12 10:27:22
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Shining Light on the Coiled-Flow Inverter—Continuous-Flow Photochemistry in a Static Mixer
摘要： We present the use of a coiled-flow inverter (CFI) for continuous-flow photochemistry at competitive photon efficiencies. The static mixer is placed inside a reaction chamber, while a dark adjacent chamber allows for orthogonal online reaction monitoring via fluorescence spectroscopy. The study of the aqueous visible-light induced degradation of fluorescein with ZnO-APTMS-Au photocatalyst showcases the challenge of uniformly irradiating photoreactors with non-planar surfaces. Fluorescence imaging is introduced as a simple method to visualize spatial gradients in the irradiance at the outer surface of such complex photoreactor geometries, allowing the analysis of photoreactor efficiency as a function of lighting configuration. We compared uniaxial and multiaxial lighting configurations and discuss the challenges associated with attaining uniform irradiance distribution of incident light on coiled-flow inverters, where chaotic advection combats light attenuation. A first calculation of the photochemical space-time yield (PSTY) for a “photo-CFI” is presented and contrasted with other photoreactor designs.
关键词： continuous-flow photochemistry,coiled-flow inverter,fluorescence imaging,ZnO-APTMS-Au photocatalyst,photochemical space-time yield
更新于2025-09-12 10:27:22
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Reusable magnetic Ag/Fe, N-TiO2/Fe3O4@SiO2 composite for simultaneous photocatalytic disinfection of E.?coli and degradation of bisphenol A in sewage under visible light
摘要： A visible-light-driven and magnetic photocatalyst Ag/Fe,N-TiO2/Fe3O4@SiO2 (AgFeNTFS) was synthesized through a multi-step method. AgFeNTFS was tested for the photocatalytic disinfection of Escherichia coli (E. coli) and degradation of bisphenol A (BPA) under visible light irradiation, separately and simultaneously. The results showed that a 6.3-log reduction in cell density of E. coli was achieved and BPA (2 mg/L) was completely removed by AgFeNTFS in the separated photocatalytic processes within 120 min. In the simultaneous process, the photocatalytic disinfection of E. coli was not influenced in the presence of BPA, but the efficiency of BPA degradation was dropped by 10%. This was likely due to the competition for the same dominant reactive species of ?O2? and H2O2 between E. coli and BPA in the simultaneous process, as evidenced by the scavenger study and the interactions between the pollutants and AgFeNTFS. Moreover, the simultaneous photocatalytic activity of E. coli disinfection and BPA degradation by AgFeNTFS was investigated in the sewage obtained from a local wastewater treatment plant. The photocatalysis treated sewage could meet with the local disinfection discharge standard with a 3-log reduction of E. coli after 90 min, and a complete removal of BPA was achieved simultaneously after 360 min. Moreover, AgFeNTFS showed high magnetic separation efficiency and had a good reusability over three cycles for the simultaneous photocatalytic disinfection and degradation of BPA in both synthetic water and sewage. This study provides insights on the application of a reusable magnetic photocatalyst for simultaneous disinfection and degradation of BPA in sewage.
关键词： Simultaneous process,Visible-light-driven photocatalyst,Magnetic photocatalyst,Bisphenol A,Disinfection
更新于2025-09-11 14:15:04
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Investigating the efficiency of α-Bismuth zinc oxide heterostructure composite/UV-LED in methylene blue dye removal and evaluation of its antimicrobial activity.
摘要： Heterostructured α-Bismuth zinc oxide (α-Bi2O3-ZnO) photocatalyst was fabricated by a facile and cost-effective, ultrasound assisted chemical precipitation method followed by hydrothermal growth technique. As synthesized α-Bi2O3-ZnO photocatalyst showed enhanced photocatalytic performance for the MB dye degradation in contrast to pure ZnO and α-Bi2O3. Light emitting diodes (UV-LED) were used in the experimental setup, which has several advantages over conventional lamps like wavelength selectivity, high efficacy, less power consumption, long lifespan, no disposal problem, no warming-up time, compactness, easy and economic installation. XRD study confirmed the presence of both the lattice phases i.e. monoclinic and hexagonal wurtzite phase corresponding to α-Bi2O3 and ZnO in the α-Bi2O3-ZnO composite photocatalyst. FESEM images showed that α-Bi2O3-ZnO photocatalyst is composed of dumbbell like structures of ZnO with breadth ranging 4-5 μm and length ranging from 10 to 11 μm respectively. It was observed that α-Bi2O3 nanoparticles were attached on the ZnO surface and were in contact with each other. Low recombination rate of photo-induced electron-hole pairs, due to the migration of electrons and holes between the photocatalyst could be responsible for the 100 % photocatalytic efficiency of α-Bi2O3-ZnO composite. In addition, photocatalyst was also observed to show the excellent antimicrobial activity with 1.5 cm zone of inhibition for 1 mg/L dose, against the human pathogenic bacteria (S. aureus).
关键词： Heterostructure,antimicrobial activity,Methylene blue,Photocatalyst,α-Bi2O3-ZnO,UV-LED,α-Bi2O3
更新于2025-09-11 14:15:04
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Influence of Semiconductor Morphology on Photocatalytic Activity of Plasmonic Photocatalysts: Titanate Nanowires and Octahedral Anatase Nanoparticles
摘要： Octahedral anatase particles (OAP) with eight exposed and thermodynamically most stable (101) facets were prepared by an ultrasonication-hydrothermal (US-HT) reaction from potassium titanate nanowires (TNW). The precursor (TNW) and the product (OAP) of US-HT reaction were modi?ed with nanoparticles of noble metals (Au, Ag or Pt) by photodeposition. Samples were characterized by X-ray di?raction (XRD), X-ray photoelectron spectroscopy (XPS), di?use re?ectance spectroscopy (DRS), scanning transmission electron microscopy (STEM) and time-resolved microwave conductivity (TRMC). The photocatalytic activity was investigated in three reaction systems, i.e., anaerobic dehydrogenation of methanol and oxidative decomposition of acetic acid under UV/vis irradiation, and oxidation of 2-propanol under vis irradiation. It was found that hydrogen liberation correlated with work function of metals, and thus the most active were platinum-modi?ed samples. Photocatalytic activities of bare and modi?ed OAP samples were much higher than those of TNW samples, probably due to anatase presence, higher crystallinity and electron mobility in faceted NPs. Interestingly, noble metals showed di?erent in?uence on the activity depending on the semiconductor support, i.e., gold-modi?ed TNW and platinum-modi?ed OAP exhibited the highest activity for acetic acid decomposition, whereas silver- and gold-modi?ed samples were the most active under vis irradiation, respectively. It is proposed that the form of noble metal (metallic vs. oxidized) as well as the morphology (well-organized vs. uncontrolled) have a critical e?ect on the overall photocatalytic performance. TRMC analysis con?rmed that fast electron transfer to noble metal is a key factor for UV activity. It is proposed that the e?ciency of plasmonic photocatalysis (under vis irradiation) depends on the oxidation form of metal (zero-valent preferable), photoabsorption properties (broad localized surface plasmon resonance (LSPR)), kind of metal (silver) and counteraction of “hot” electrons back transfer to noble metal NPs (by controlled morphology and high crystallinity).
关键词： silver,platinum,gold,photocatalyst morphology,faceted titania,morphology-governed activity,plasmonic photocatalysis,octahedral particle,titanate nanowire,noble metal
更新于2025-09-11 14:15:04
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One-pot microwave-assisted green synthesis of amine-functionalized graphene quantum dots for high visible light photocatalytic application
摘要： Nowadays, graphene quantum dots (GQDs) have gained a huge interest in the field of visible-range photocatalysts because of their tunable band gap and stable photochemical properties. In this work, amine-functionalized GQDs (AGQDs) were successfully prepared by one-step microwave-assisted conversion of glucose, H2O2, and NH3 solution. The obtained quantum dots possess the high quality of graphene structure with the average size of 3.78 nm as well as exhibit a strong green fluorescence with a high quantum yield. Interestingly, the amine-functionalized dots perform outstanding visible-light absorption. To further investigate photocatalytic properties, a composite of AGQDs and TiO2 was then prepared by a simple mixing route. The hybrid material showed high catalytic activity of dye degradation under visible light irradiation, which indicates the key role of AGQDs in enhancing light absorption and induced electron-hole separation. The current study may open a new way for construction of effective visible light photocatalytic systems with a cost-effective, simple approach.
关键词： Fluorescent visible light photocatalyst,Graphene quantum dots,Amine functionalized,Dyes photodegradation
更新于2025-09-11 14:15:04
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Sulfur Dioxide Degradation by Composite Photocatalysts Prepared by Recycled Fine Aggregates and Nanoscale Titanium Dioxide
摘要： To alleviate the heavy burden on landfilling, construction and demolition wastes (C&DWs) are recycled and reused as aggregates in cementitious materials. However, the inherent characteristics of recycled fine aggregates (RFA), such as the high crushing index and high-water absorption, magnify the reusing difficulty. Nevertheless, attributing to the high porosity and high level of calcium hydroxides existing in the old mortar, RFA is featured with a high specific surface area and a high alkalinity. These features are useful to augment the total photo-degradation of SO2 by nano-TiO2 (NT) intermixed mortar, leading RFA to be an excellent potential carrier to load nano-TiO2 and prepare the composite photocatalyst. Hence, this study proposed to load NT onto the surface of RFAs and river sands (RSs) (the control) by the soaking method, preparing composite photocatalysts denoted as NT@RFA and NT@RS, respectively. The prepared composite photocatalysts were then utilized as sands in photocatalytic mortar to evaluate for SO2 degradation. Experiments identified a 50% higher amount of NT was loaded onto the surface of FRA relative to the control. This higher loading amount plus higher alkalinity ultimately translated into a higher photocatalytic activity. In addition, the mortar containing NT@RFA exhibited 46.3% higher physiochemical absorption and 23.9% higher photocatalytic activity than that containing NT@RS. In addition, the durability, embodied by the reuse and anti-abrasive properties, of NT@RFA exceeded that of NT@RS. The overall findings reveal that the NT@RFA not only garners beneficial effect from the high porosity but also generates positive effect from the high alkalinity. Though a number of studies deal with building materials with NT, this study is the first to load NT onto RFA and prepare composite photocatalysts which were then used as fine aggregates in building materials. Consequently, this study proves the potential high-added-value reusability of RFA in green construction materials and provides a low-cost, high-efficiency approach to degrade atmospheric SO2.
关键词： construction waste,composite photocatalyst,nano-TiO2,SO2 degradation,recycled fine aggregate,photocatalytic mortar
更新于2025-09-11 14:15:04
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Cocatalyst-free Plasmonic H <sub/>2</sub> Production over Au/Ta <sub/>2</sub> O <sub/>5</sub> under Irradiation of Visible Light
摘要： Gold (Au)-modi?ed tantalum(V) oxide (Ta2O5) prepared by using a colloid photodeposition method produced H2 without the aid of a cocatalyst under visible light irradiation due to the su?ciently negative potential of electrons injected from Au nanoparticles into the conduction band of Ta2O5 (10.47 V).
关键词： Pt free,Plasmonic photocatalyst,H2 evolution
更新于2025-09-11 14:15:04