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Coupling of Ag2CO3 to an optimized ZnO photocatalyst: Advantages vs. disadvantages
摘要： With the aim of improving the photocatalytic properties of a previously optimized zinc oxide photocatalyst, the effect of the incorporation of different amounts of Ag2CO3 on the aforementioned ZnO has been studied. For this purpose we report the synthesis, by means of simple precipitation procedures, of bare ZnO and Ag2CO3 samples as well as the coupled materials ZnO/Ag2CO3 (X) (where X = 1%, 2%, 4% and 5% in molar percentages). Both, single and coupled materials have been characterized by different techniques (XRD, XRF, N2-absorption, SEM, TEM, UV–vis/DRS and XPS). To assess the advantages or disadvantages that Ag2CO3 addition could have over the optimized ZnO, the photocatalytic properties have been established by following the photo-degradation of selected toxic molecules, both in the UV and in the visible, as well as using complementary techniques of liquid medium analyses (TOC and Atomic Emission Spectrometry with plasma ICP). Three selected substrates were chosen: Rhodamine B (RhB) as a dye, and phenol and caffeine as colourless recalcitrant toxic molecules.
关键词： Visible-Photocatalysis,Zinc oxide,Dyes,Ag2CO3,Caffeine,Phenol
更新于2025-09-11 14:15:04
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Enhanced photocatalytic activity and stability of AgBr/BiOBr/graphene heterojunction for phenol degradation under visible light
摘要： In this work, we have reported synthesis of AgBr/BiOBr photocatalyst supported on graphene (Gr) using facile precipitation method. AgBr/BiOBr/Gr was characterized using various spectral techniques like FESEM, TEM, XRD, FTIR, XPS, Raman and PL analyses. AgBr/BiOBr/Gr had improved visible light absorption. PL studies indicated the reduction in recombination of photogenerated electron hole pair of AGBr/BiOBr/Gr. AFM analysis con?rmed the thickness of AGBr/BiOBr/Gr was less than 8.0 nm. The higher dispersibility of photocatalyst was ascertained by Tyndall effect. AgBr/BiOBr/Gr photocatalyst was effectively used for the photodegradation of phenol from simulated water. The phenol degradation process was remarkably in?uenced by adsorption process. The concurrent adsorption and photocatalytic was effective for degradation of phenol. The phenol was completely mineralized into CO2 and H2O in 6 h. The degradation process followed pseudo ?rst order kinetics. The results con?rmed that integration of AgBr/BiOBr with graphene caused an increase in photocatalytic activity due to reduced recombination of photogenerated electron hole pair and electron sink behavior of graphene for photogenerated electrons of BiOBr. AgBr/BiOBr/Gr photocatalyst displayed signi?cant stability and recyclability for ten catalytic cycles.
关键词： Enhanced photocatalytic activity,Recyclability,Phenol degradation,Graphene,AgBr/BiOBr,Heterojunction formation
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [Author(s) 6TH INTERNATIONAL CONFERENCE ON PRODUCTION, ENERGY AND RELIABILITY 2018: World Engineering Science & Technology Congress (ESTCON) - Kuala Lumpur, Malaysia (13–14 August 2018)] - Development of nanocomposites on the basis of graphene nanoplatelets
摘要： The prospects for using a phenol-formaldehyde resin (PFR) as a reactive surfactant in the preparation of highly concentrated dispersions of carbon nanostructured materials (up to 1 %) are considered in the present paper. Modifying graphene nanoplatelets (GNPs) with this surfactant promotes the effect of targeted self-assembly of carbon nanoparticles in solution (with decreasing pH), which makes it possible to obtain nanocomposites with improved properties. It is important that the use of highly concentrated dispersions of PFR-modified GNPs in the production of nanocomposite materials does not require a preliminary removal of the surfactant. Based on the resulting dispersion, the mesoporous carbon/GNPs composite with a developed surface (3000 ? 4000 m2 g?1) was successfully synthesized. It can be used as an electrode material for supercapacitors and an adsorbent of organic and inorganic species for wastewater treatment purposes.
关键词： graphene nanoplatelets,reactive surfactant,self-assembly,nanocomposites,mesoporous carbon,phenol-formaldehyde resin
更新于2025-09-10 09:29:36
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STUDY OF AN ANNULAR PHOTOREACTOR WITH TANGENTIAL INLET AND OUTLET.II. THE UV/H <sub/>2</sub> O <sub/>2</sub> REACTIVE FLOW
摘要： The concentration profiles of species involved in the degradation of phenol by an advanced oxidation processes (AOP) are modeled using a CFD tool, in an annular reactor whose fluid dynamics was the object of a previous study. The reactive flow was fully described together with the kinetic model, which encompasses large kinetic constants, such as 101 0 L mol-1 s-1, and the radiation field. Phenol degradation can be simulated b y using relaxation factors of 1012 kg m-3 s-1 at least. The hydroxyl radical concentration profile, depends on the radiation field, performed by the discrete ordinate (DO) and the discrete transfer (DT) methods. Phenol can be completely degraded along the reactor. A centrifugal effect was observed, with higher concentration of degradation products along the inner wall at the reactor outlet.
关键词： Fluence rate,Advanced oxidation process,Computational fluid dynamics,Phenol degradation,Degradation kinetics,Parameter estimation,Modeling
更新于2025-09-10 09:29:36
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Fabrication of Ag3VO4 decorated phosphorus and sulphur co-doped graphitic carbon nitride as a high-dispersed photocatalyst for phenol mineralization and E. Coli disinfection
摘要： In this work, we have successfully anchored Ag3VO4 (AV) onto P and S co-doped g-C3N4 (PSGCN) to prepare high-dispersible AV/PSGCN photocatalyst via a deposition-precipitation method. The P and S co-doped g-C3N4 was synthesized via thermal polycondensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. AV/PSGCN was characterized using various spectral techniques. The atomic force analysis indicated that the thickness of AV/PSGCN was less than 3.0 nm. The zeta potential and Tyndall effect experiments ascertained formation of the well-dispersed suspension of AV/PSGCN in water. The co-doping resulted in lowering optical band gap of g-C3N4. The photoluminescence and electrochemical impedance analysis indicated suppression in recombination of photogenerated electron and hole pairs in AV/PSGCN. The photodegradation of phenol followed pseudo-first order kinetics. Hydroxyl radicals and holes were the two main reactive species for photodegradation of phenol. The COD, HPLC and LC-MS analyses confirmed mineralization of phenol in 6 h. Unlike conventional slurry type photo-reactors, AV/PSGCN was not magnetically agitated during photocatalytic reactions. AV/PSGCN exhibited significant antibacterial activity for E.Coli disinfection. The photodegradation of phenol and bacterial disinfection occurred through hole and hydroxyl radical formation mechanism.
关键词： Phenol degradation,Enhanced photocatalytic activity,Heterojunction formation,Ag3VO4,Antibacterial activity,Co-doped g-C3N4
更新于2025-09-10 09:29:36
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A BODIPY-PHENOL-BASED SENSOR FOR SELECTIVELY RECOGNIZING THREE BASIC ANIONS
摘要： A novel BODIPY-based anion sensor 1 bearing di-tert-butyl phenol unit was designed and prepared. In the presence of three basic anions F-, AcO- or H2PO4-, 1 exhibited two novel partially overlapped red-shift absorption bands at 718 nm and 757 nm, respectively. The formation of allotropic structures, after deprotonation of phenol OH, is responsible for these two emerging bands. Fluorescence quenching was also observed due to intramolecular charge transfer (ICT) from phenolate to BODIPY core. As results revealed, the anion affinity mainly depended on the acidity of binding site OH and the basicity of the target anion. Moreover, two bulky tert-butyl groups cannot effectively exclude the approach of large anions to phenol OH, but can facilitate the formation of allotropic resonance structures.
关键词： BODIPY,phenol,steric effect,anion sensor,deprotonation
更新于2025-09-09 09:28:46
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Ag modified ZnS for photocatalytic water pollutants degradation: influence of metal loading and preparation method
摘要： In this paper, the photocatalytic degradation of organic pollutants was investigated using Ag/ZnS nanoparticles at different noble metal loadings. The photocatalysts were prepared at room temperature by two different methods: photodeposition and chemical reduction. The obtained samples were characterized by Specific surface area measurement, X-ray photoelectron spectroscopy, X-ray Powder diffraction, ultraviolet-visible diffuse reflectance and Raman spectroscopy. The X-ray photoelectron spectroscopy spectra showed that Ag is present on ZnS surface as intermediate state between nanostructured Ag0 and Ag2O. Moreover, the addition of silver caused a significant change of the absorption spectrum of bare ZnS, resulting in higher absorbance in the visible region, due to the Ag surface plasmon band. Methylene blue (MB) was used to evaluate the photocatalytic activity of the prepared samples. The best photocatalytic activity was observed using the sample at 0.1 wt% Ag loading prepared by chemical reduction method. In particular, the almost complete MB degradation was achieved using UV-LEDs as light sources and 6 g L-1 of catalyst dosage. Finally, the optimized photocatalyst was also effective in the degradation of phenol in aqueous solution under UV irradiation.
关键词： Ag/ZnS,methylene blue,silver loading,UV irradiation,phenol
更新于2025-09-09 09:28:46
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Phenol-functionalized polymerization control additives for negative tone epoxide crosslinking molecular resists
摘要： Controlling undesired polymerization in nominally unexposed regions is critical to achieving high-resolution, defect-free patterns when using negative tone molecular resists based on the crosslinking of epoxides. Two onium salt additives, a photodecomposable nucleophile (PDN) and a photoacid generator (PAG), were functionalized with phenols in order to investigate their use as generalized additives capable of slowing crosslinking and improving the resolution of a variety of epoxide resists. Presented here is a phenol-functionalized PDN [tris(4-hydroxyphenyl)sulfonium tri?ate (TPS-OH-Tf )] and a phenol-functionalized PAG [tris(4-hydroxyphenyl)sulfonium antimonate (TPS-OH-SbF6)] used in combination with a model epoxide resist (4-Ep). Utilizing additives that contained phenols resulted in a decrease in resist sensitivity, but enabled higher additive loadings which could be used to offset this loss in sensitivity. Using TPS-OH-SbF6 did not provide enough polymerization control to prevent line broadening, and the use of TPS-OH-Tf was still required to achieve sub 35 nm 1:1 line:space patterns. Adding TPS-OH-Tf was also found to improve pattern collapse behavior at reduced (<25 nm) feature sizes. Initial patterning using 100 keV electron-beam lithography showed that the resolution of 4-Ep was improved to 15 nm 1:1 line:space patterns using these phenol-functionalized additives and demonstrate the potential of these additives to improve the resolution of a variety of epoxide crosslinking molecular resists.
关键词： phenol-functionalized additives,polymerization control,molecular resists,negative tone epoxide crosslinking,high-resolution patterning
更新于2025-09-09 09:28:46
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Novel photocatalytic system Fe-complex/TiO2 for efficient degradation of phenol and norfloxacin in water
摘要： Photocatalysis is one of the effective strategies to eliminate various organic pollutants in water body. In this paper we have prepared a series of new composite photocatalysts to degrade phenol and norfloxacin under visible light irradiation. They were [FeII(dpbpy)2(H2O)2]/TiO2, [FeII(dpbpy)(phen)2]/TiO2 and [FeII(dpbpy)(bpy)2]/TiO2 (dpbpy: 2,2′-bipyridine-4,4′-diphosphoric acid, phen: 1,10-phenanthroline, bpy: 2,2-bipyridyl). The results show that their photocatalytic performance and cyclic stability are much better than that of pure TiO2 or P25. Phenol can be degraded almost completely and the active groups or substituents of norfloxacin (NOR) can be destroyed also, which greatly reduced the biological toxicity of phenol and norfloxacin in water. The possible mechanisms of improving the photocatalytic activity and stability of TiO2 by using Fe-complex are proposed based on free radical capture test and density functional theory calculation. It is clearly that the interfacial interaction between Fe-complex and titanium dioxide directly affects the photocatalytic activity and stability of the composite photocatalyst. The conjugated structure of the complexes plays a crucial role.
关键词： Photocatalystic degradation under visible light,Phenol,Norfloxacin,Fe-complex/TiO2 composite
更新于2025-09-09 09:28:46
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Metal-free photocatalytic aerobic hydroxylation of benzene catalyzed by the commercially available quinoline sulfate
摘要： Metal- free photocatalytic aerobic hydroxylation of benzene to phenol is achieved by using the low-cost commercially available quinoline sulfate (QuH2SO4) as the photocatalyst. The reaction conditions are optimized and a high phenol yield of 11.3% is obtained under the optimal reaction conditions. It is found that the [QuH]+ cation is the catalytic active species and its planar structure is crucial for its effect interaction with benzene. Moreover, the influence of the coupled anion on the photocatalytic activity of the [QuH]+ cation is investigated and discussed.
关键词： Metal- free,Photocatalysis,Hydroxylation of benzene,Phenol,Quinoline sulfate
更新于2025-09-04 15:30:14