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BiOBr/Ag6Si2O7 heterojunctions for enhancing visible light catalytic degradation performances with a sequential selectivity enabled by dual synergistic effects
摘要： Efficient separation of photogenerated electron-hole pairs is always one of the key factors boosting visible light photodegradation efficiency. Till now, there are few reports on the synergistic competitive consumption of photogenerated active species and the synergistic adsorption of organic contaminants to promote the performance of a designed heterojunction. Herein, we design and construct a novel BiOBr/Ag6Si2O7 heterojunction with the dual synergistic effects towards methylene blue (MB) and methyl orange (MO). The dual synergistic effects could avoid the combination of photogenerated h+/e? pairs, improve the adsorption efficiency, and even regulate the photodegradation efficiency. Thus, for an aqueous mixture of MB and MO, the BiOBr/Ag6Si2O7 photocatalyst exhibits largely improved adsorption capacities of the dyes by a multi-layer adsorption mode. Moreover, the photocatalyst could further promote the photodegradation rate of MO while slow that of MB due to the competitive consumption of photogenerated active species, showing a sequential selectivity phenomenon. Thanks to the dual synergistic effects, the adsorption capacity of MO increases 1379% higher than that of neat MO solution, and the photodegradation time decrease from 30 to 12 min with a rate constant of 0.22 min?1, 38% higher than that of neat MO solution.
关键词： BiOBr,Silver silicates,Visible light photodegradation,Heterojunctions,Photocatalysts
更新于2025-09-11 14:15:04
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Bi4NbO8Cl {001} nanosheets coupled with g-C3N4 as 2D/2D heterojunction for photocatalytic degradation and CO2 reduction
摘要： Photocatalytic activity is largely restricted by insufficient photoabsorption and intense recombination between charge carriers. Here, we first synthesized Bi4NbO8Cl nanosheets with {001} exposing facets by a molten-salt growth method, which shows largely promoted photocatalytic performance for the degradation of tetracycline (TC) and bisphenol A (BPA) in comparison with Bi4NbO8Cl particles obtained by solid-state reaction. The 2D/2D Bi4NbO8Cl/g-C3N4 heterojunction photocatalysts were then fabricated via high-energy ball-milling and post-sintering to realize intimate interfacial interaction. The photocatalytic activity of all the Bi4NbO8Cl/g-C3N4 composites largely enhances compared to Bi4NbO8Cl nanosheets and g-C3N4, also far exceeding the mechanically-mixed Bi4NbO8Cl nanosheets and g-C3N4. The impact of different reaction parameters on the photocatalytic degradation activities was investigated, including catalyst concentration, pH value and TC concentration. In addition, Bi4NbO8Cl/g-C3N4 also presents improved photocatalytic CO2 reduction activity for CO production. The large enhancement on photocatalytic activity of Bi4NbO8Cl/g-C3N4 composites is owing to the synergistic effect of favorable 2D/2D structure and construction of type II heterojunction with intimate interfacial interaction, thus boosting the charge separation. The formation of type II heterojunction was evidenced by selective photo-deposition of Pt and MnOx, which demonstrate that the reductive sites and oxidative sites are on Bi4NbO8Cl nanosheets and g-C3N4, respectively. This work may provide some insights into fabrication of efficient visible-light driven photocatalysts for environmental and energy applications.
关键词： g-C3N4,photodegradation,Bi4NbO8Cl nanosheets,CO2 reduction,heterojunction
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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Impact of TiO2 Nanotubes’ Morphology on the Photocatalytic Degradation of Simazine Pollutant
摘要： There are various approaches to enhancing the catalytic properties of TiO2, including modifying its morphology by altering the surface reactivity and surface area of the catalyst. In this study, the primary aim is to enhance the photocatalytic activity by changing the TiO2 nanotubes’ architecture. The highly ordered infrastructure is favorable for a better charge carrier transfer. It is well known that anodization affects TiO2 nanotubes’ structure by increasing the anodization duration which in turn in?uence the photocatalytic activity. The characterizations were conducted by FE-SEM (?end emission scanning electron microscopy), XRD (X-ray diffraction), RAMAN (Raman spectroscopy), EDX (Energy dispersive X-ray spectroscopy), UV-Vis (Ultraviolet visible spectroscopy) and LCMS/MS/MS (liquid chromatography mass spectroscopy). We found that the morphological structure is affected by the anodization duration according to FE-SEM. The photocatalytic degradation shows a photodegradation rate of k = 0.0104 min?1. It is also found that a mineralization of Simazine by our prepared TiO2 nanotubes leads to the formation of cyanuric acid. We propose three Simazine photodegradation pathways with several intermediates identi?ed.
关键词： Simazine,TiO2 nanotubes,anodization,photodegradation mechanism,photocatalytic,photocatalyst
更新于2025-09-10 09:29:36
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Applications of polystyrene/graphite composites in water purification as a semiconductor visible-light photocatalyst for organic pollutant degradation
摘要： The aim of this study was to prepare a polymer/graphite composite thin film as a cheap, and nontoxic photocatalyst that could be activated by visible light. It was characterized using ultraviolet/visible spectrophotometry and X-ray diffraction. Scanning electron microscopy was used to examine the photocatalyst surface before and after a photodegradation process. The photocatalyst showed activity under visible light and was used for the photodegradation of methylene blue (MB) and rhodamine B (Rh-B) as target pollutants. The process was studied with different pH values, initial dye concentrations, and light intensities from the radiation source to evaluate their effects. The results revealed that the photodegradation was affected by the initial dye concentration, and also showed that the best conditions for the photodegradation reactions of both dyes were an alkaline medium and a light intensity of 80 wt. The films prepared under the conditions reported herein could be promising materials in water purification.
关键词： Rhodamine B,Methylene blue,Photocatalyst,Photodegradation
更新于2025-09-10 09:29:36
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Highly efficient solar light-assisted TiO2 nanocrystalline for photodegradation of ibuprofen drug
摘要： Pure anatase, pure brookite, and anatase/brookite heterojunction (ABH) TiO2 with tunable anatase/brookite ratios were prepared via a facile hydrothermal process using Titanium (III) sulfate, as precursor and different glycine/NaOH ratios, as pH adjusting reagents. The obtained samples were characterized by XRD, Raman, FT-IR, FE-SEM, TEM, EDX, BET surface area, UV-vis-DRS, XPS, and PL. The photocatalytic performance of as-synthesized catalysts was evaluated by photodegradation of ibuprofen under simulated solar light. The photodegradation rate of A/B heterojunction TiO2 photocatalysts was greater 12.5, 8.5 and 1.6 times than that the pure brookite, pure anatase, and the commercial P-25, respectively. The complete ibuprofen mineralization (100%) was performed under simulated solar light within 5 h using the photocatalyst obtained at pH 10 (i.e. 1:3 glycine/NaOH volume ratio), however, the commercial P-25 is 75%. The optimum sample containing 61.8%A/38.2%B exhibits the best photocatalytic activity due to it has a mesoporous structure, high surface area, and the low PL intensity.
关键词： Ibuprofen,Solar light,Photodegradation,Anatase-brookiteTiO2,Photocatalyst
更新于2025-09-10 09:29:36
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Removal of Polycyclic Aromatic Hydrocarbons (PAHs) from Industrial Soil with Solar and UV Light
摘要： The aim of the present study was to evaluate and compare the efficiencies of solar/UV based processes for polycyclic aromatic hydrocarbon (PAH) removal from soils with and without additives. This study provided some useful information to understand the remediation of PAH-contaminated soils by photocatalytic techniques. Soil samples were taken from an industrial area, and PAH removal processes were applied to the samples for 24 h in ambient air conditions. Also, UV experiments (UVA and UVC) were conducted in a specially designed apparatus. TiO2 and H2O2 were used as additives at the doses of 1%, 10%, and 20% of dry soil weight during ambient air experiments. Only 35% 12 PAH removal from soil was obtained in ambient air conditions. This value was calculated as 90% and 86% for UVA and UVC applications, respectively. Results indicated that the use of additives contributed to the photodegradation of PAHs under real conditions. The most efficient doses were 20% for TiO2 (89% PAH removal) and 1% for H2O2 (88% PAH removal). When the removal efficiencies were evaluated in terms of compounds, it was observed that the removal ratios were elevated for both lighter and heavier PAH compounds with the addition of additives. 3-ring and 4-ring PAH compounds were removed at higher ratios in comparison with 5-,6-ring ones for samples with and without additives.
关键词： UV,Ambient air,photodegradation,PAHs,H2O2,TiO2
更新于2025-09-10 09:29:36
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Facile Synthesis of Carbon Nanotubes Covalently Modified with ZnO Nanorods for Enhanced Photodecomposition of Dyes
摘要： Utilizing a one-pot solvothermal procedure novel one-dimensional zinc oxide-carbon nanotube nanohybrids (ZnCT) were synthesized in alcohol-alkali solution, free of catalytic assistance. The ZnCT hybrids were prepared through covalent modification of zinc oxide nanorods (ZnO NRs) with functionalized carbon nanotubes (f-CNTs). The morphology and microstructure of as-prepared ZnCT hybrids were characterized by scanning electron microscopy (SEM), powder X-ray diffraction, Raman, X-ray photoelectron and UV-vis absorption spectroscopies. SEM images of the ZnCT hybrids indicated that the ZnOethanol NRs grew longer along the vertical radial (0001) surface and aggregated to a lesser extent than the analogous ZnOmethanol NRs. Photodegradation analysis showed that the off-white ZnCTethanol hybrid with ascendant UV-visible light absorption had displayed superior photocatalytic activity towards Rhodamine B (RhB) dyes than either pure ZnOethanol, ZnOmethanol NRs or ZnCTmethanol hybrid, among which the photocatalytic activity of ZnOethanol NRs was better than that of ZnOmethanol NRs. Raman and X-ray photoelectron spectroscopy analyses confirmed a strong interaction between f-CNTs and ZnOethanol NRs in ZnCTethanol hybrid, in which Zn ions were chemically bonded to negatively charged oxygen-containing groups at the graphene-like surface of f-CNTs. The enhanced separation lifetime of the photogenerated electron-hole observed by surface photovoltage and photocurrent measurements of the ZnCTethanol hybrid was attributed to the efficient covalent linking of Zn-O-C and close contact configuration between the f-CNTs and ZnOethanol NRs. Further controlled photodegradation and electron spin resonance (ESR) analyses revealed that the photodegradation of RhB dyes resulted from photogenerated holes, and radical species, such as ?O2?、?OH?, which were formed in-situ. Details of the photocatalytic mechanism were also explored herein.
关键词： Solvothermal synthesis,ZnO nanorods,Carbon nanotubes,Dyes,Photodegradation
更新于2025-09-10 09:29:36
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Photodegradation of metoprolol using a porphyrin as photosensitizer under homogeneous and heterogeneous conditions
摘要： Porphyrins are known as effective photosensitizers and can be an interesting key in phototreatment of water contaminated with micropollutants such as pharmaceuticals. They already showed to be efficient photocatalysts for the degradation of dyes, chlorophenols and other pollutants. This work demonstrates the applicability of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (H2TF5PP) as photosensitizer for treatment of water contaminated with metoprolol, a highly prescribed β-blocker, which is not completely removed in sewage treatment plants. Studies were firstly developed under homogeneous conditions with simulated solar radiation and porphyrin was found to be efficient in the photodegradation of metoprolol, following a pseudo-first order kinetics with ca. 90% metoprolol degradation after 12 h. Experiments in presence of scavengers confirmed the mechanism of degradation via singlet oxygen. Appearance of several new peaks in HPLC chromatograms indicates the formation of products, identified by HPLC-MSn. Furthermore, the porphyrin was immobilized on a silica support and used as heterogeneous photocatalyst in degradation of metoprolol. Experiments using this heterogeneous photocatalyst under real solar irradiation were also performed, and similar results were obtained. Kinetic comparison of metoprolol photodegradation in buffer solution and in real wastewater treatment plant effluent showed that the efficiency of the immobilized porphyrin was not decreased by the complex matrix of the effluent.
关键词： Metoprolol,Wastewater,Porphyrin,Photodegradation,Photocatalysis
更新于2025-09-10 09:29:36
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Photodegradation of fluazaindolizine in aqueous solution with graphitic carbon nitride nanosheets under simulated sunlight illumination
摘要： The photodegradation of fluazaindolizine (FZDL) under simulated sunlight irradiation was accelerated by the catalysis of graphitic carbon nitride (g-C3N4). Under optimum conditions, such as 5 mg of amount and dispersion, the photodegradation half-life was dramatically enhanced to 2.7 h. More importantly, the pathway of degradation by g-C3N4 was different from both direct photolysis and the catalysis by titanium oxide, with particular negative ions of m/z 221 and 195, corresponding to the cleavage of sulfamide bond and the ring opening of imidazole, respectively. In addition, hydroxyl and superoxide radicals played important roles in photodegradation. The results enriched not only the study of FZDL photodegradation but also the application of g-C3N4. It also suggested the possibility of the water purification by photodegradation for pesticide removal in real life.
关键词： Advanced oxidation processes,Transformation products,Fluazaindolizine,Mass Spectrometery,Photodegradation,Graphitic carbon nitride
更新于2025-09-10 09:29:36