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The fabrication of floating Fe/N co-doped titania/diatomite granule catalyst with enhanced photocatalytic efficiency under visible light irradiation
摘要： Powdery photocatalyst has long been studied, yet its several disadvantages such as light-harvesting and recyclability in suspension system are the bottlenecks for practical application. The recent report on floating photocatalyst provided an alternative method to solve the above problem. In this work, TiO2 nanoparticles were co-doped by iron and nitrogen, and then dispersed onto natural porous mineral diatomite via sol-gel method. The composite powder was granulated to produce floating granule catalyst (Fe/N co-doped TiO2/diatomite hybrid granule), denoted as FN-TDHG. Its various physicochemical properties such as light absorbance, crystallinity, surface condition as well as morphology were systematically analyzed. The synergy between Fe and N dopants, as well as diatomite and TiO2 were studied. The photoactivity of FN-TDHG was investigated via the degradation towards tetracycline (TC) solution under visible light irradiation, and then the optimal co-doping amount and granule dosage were determined. The optimal granule catalyst presented its removal rate of TC as 96.5% within 150 min. Moreover, floating FN-TDHG could simply be filtrated from the surface of water matrix, and presented good reusability after 5 repetitions. This photocatalytic granule is hopefully considered suitable to be applied in environmental remediation.
关键词： Fe/N co-doped,Diatomite,Floating,Visible light,Tetracycline
更新于2025-09-23 15:21:21
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Effect of Eu3+ ions on optical and fluorescence studies of Nd3+ ions doped zinc-lithium fluoroborate glasses
摘要： Nd3+ single and Nd3+/Eu3+ co-doped ZnF2-LiF-Na2CO3-Bi2O3-H3BO3, zinc lithium fluoroborate (ZLFNBiB) glasses with good optical properties have been prepared by high temperature melt-quenching method. The single and co-doped samples exhibiting emission bands centered at 874, 1058 and 1330 nm under the excitation of 808 nm laser diode (LD). The photoluminescence spectra for co-doped glasses were recorded under the 394 and 464 nm of xenon lamp as excitation sources. The Judd-Ofelt intensity parameters were calculated from optical absorption spectrum and radiative parameters from the emission spectrum of 0.5 mol% of Nd3+ doped glass. The large stimulated emission cross-section and branching ratio values are evaluated and compared with the other Nd3+ doped systems, the energy transfer from Eu3+ to Nd3+ ions is observed and thoroughly discussed from NIR emission spectra (λexc = 394 nm) of co-doped glasses. The decay profiles are recorded for all the concentrations of co-doped samples and the experimental lifetimes (τexp) were obtained from the decay profiles. The binding energy and Urbach energy values of prepared glass samples were calculated and discussed.
关键词： Spectroscopic properties,Fluorescence,Energy transfer,Lifetime.,Nd3+/Eu3+-co-doped glasses
更新于2025-09-23 15:21:21
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Investigations on structural, optical and dielectric properties of Mn doped ZnO nanoparticles synthesized by co-precipitation method
摘要： Mn doped ZnO (ZnO:Mn) nanopowders with Mn:ZnO ratio from 0 to 3% were successfully synthesized by co-precipitation method. Their structural, optical, dielectric and conducting properties were investigated. All samples crystallize in the hexagonal wurtzite structure. The change in lattice parameters, bond length and preferential crystalline orientation for Mn doped ZnO samples indicates Mn2+ ions incorporation in ZnO lattice. Both micro-strain and dislocation density decrease due to doping whereas the average crystallite size increases suggesting the improvement of crystalline quality. The optical transmission in the visible region was improved as a result of doping. The observed decrease in ac conductivity (??????) with increasing Mn content is associated with the increase of defects amount. Cole-Cole plots of all samples were fitted to a circuit consisting in a parallel combination of a resistance and a constant phase element (CPE).
关键词： conductivity,optical properties,Mn doped ZnO,dielectric properties,XRD
更新于2025-09-23 15:21:21
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Photocatalytic removal of diclofenac by Ti doped BiOI microspheres under visible light irradiation: Kinetics, mechanism, and pathways
摘要： BiOI microspheres doped with different amounts of Ti were fabricated and used to remove diclofenac (DCF) from water under visible light irradiation. The fabricated photocatalysts were well characterized. Ti doped BiOI microspheres were found to exhibit higher photocatalytic activity towards DCF under visible light compared with BiOI. Ti doping broadened the band gap of BiOI, which leads to a more negative conduction band edge and a higher reducing activity of photo-generated electrons, thus facilitates ·O2? production during photocatalysis. Among all the fabricated Ti doped BiOI microspheres, TB450 exhibited the highest DCF photocatalytic removal efficiency. Specifically, 99.2% of DCF (C0 = 10 mg L?1) was removed by TB450 (250 mg L?1) at pH 5 within 90 min under visible light irradiation. Scavenger experiments indicated that active species including h+, ·O2? and H2O2 played important roles in the photocatalytic process. The degradation pathway of DCF was elucidated by theoretical density functional theory (DFT) and by-products identification through liquid chromatograph mass spectrometer (LC-MS) analysis. DCF degradation pathway mainly included hydroxylation and the cleavage of C\N bond. DFT calculation can well interpret the degradation mechanism and the sites of DCF molecule with high radical-attack Fukui index (f0) exhibit high reactivity. Acidic condition was found to facilitate the DCF photocatalytic removal. Due to strong photo-stability, Ti doped BiOI microspheres contained good visible-light-driven (VLD) photocatalytic removal efficiency for DCF in the fourth consecutive reused cycle. Ti doped BiOI microspheres can be employed as a cost-effective and high-efficient material to efficiently degrade emerging contaminants (e.g., pharmaceutical) from wastewaters under visible light conditions.
关键词： Ti doped BiOI microspheres,Photocatalysis,Diclofenac,Reuse,Degradation pathway,DFT calculation
更新于2025-09-23 15:21:21
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Observation of Optical Band-Gap Narrowing and Enhanced Magnetic Moment in Co-Doped Sol–Gel-Derived Anatase TiO <sub/>2</sub> Nanocrystals
摘要： The magnetic behavior of TiO2 and doped TiO2 nanocrystals has been a challenge due to the unambiguous nature of defects present in oxide semiconductors. Here, a simple, low-temperature sol?gel method is developed for the synthesis of low-dimensional and highly efficient stable anatase TiO2 nanocrystals. The X-ray powder diffraction pattern and Raman spectra confirm the formation of a single-phase anatase structure of TiO2. High-resolution transmission electron microscopy studies reveal the crystalline nature of the sol?gel-derived nanocrystals. The increase in lattice parameters together with the shifting and broadening of the most intense Eg(1) mode in micro-Raman spectra of Co-doped TiO2 nanocrystals indicate the incorporation of Co in TiO2. Shifting of the absorption edge to the visible region in UV?visible spectra indicates narrowing of the band gap due to Co incorporation in TiO2. X-ray photoelectron spectra confirm the presence of Co2+ and Co3+ in Co-doped TiO2 samples. Oxygen vacancy defects lead to the formation of bound magnetic polarons which induces a weak ferromagnetic behavior in air-annealed 3% Co-doped TiO2 at room temperature. It is observed that irrespective of the dopant ion, whether magnetic or nonmagnetic, the overlapping of bound magnetic polarons alone can induce ferromagnetism, while the magnetic impurities give rise to an enhanced paramagnetic moment for higher Co concentrations. A detailed understanding on the variation of these magnetic properties by estimating the concentration of bound magnetic polarons is presented, which is in corroboration with the photoluminescence studies. The observed band-gap narrowing in Co-doped TiO2 nanostructures and the mechanism underlying the magnetic interactions associated with the magnetic impurity concentration are advantageous from an applied perspective, especially in the field of spintronic and magneto-optic devices.
关键词： spintronic,magnetic moment,nanocrystals,optical band-gap narrowing,TiO2,magneto-optic devices,Co-doped,sol?gel
更新于2025-09-23 15:21:21
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Tuning optical and magnetic properties of nanocrystalline BaTiO3 films by Fe doping
摘要： Fe-doped BaTiO3 is a promising multiferroics material due to its appealing physical properties and potential applications in sensors, transducers and non-volatile memories and multilayer capacitors. Herein, Fe-doped BaTiO3 nanocrystalline films were deposited on silicon substrates by chemical solution route. The relation between Fe content and the optical and magnetic properties of the samples was analyzed. X-ray diffraction data show that the films are tetragonal with P4mm space group. The atomic force microscopy measurement indicates that the film surface roughness increases with Fe composition. The optical response behavior of the films was investigated by Adachi’s dielectric function model with fitting ellipsometric spectra in the photon energy 1.5–4.13?eV. With increasing Fe content, the real part of dielectric functions gradually decreases in the transparent region. Moreover, EOBG (the optical band gap) is reduced with increasing Fe composition x, and the relationship between them is EOBG = (3.817–1.440 × x) eV. All Fe-doped films show weak ferromagnetism coming from the bound magnetic polarons and exchange interaction between oxygen vacancies and Fe3+ in the films. When iron content x exceeds 0.06, the magnetization values of the samples exhibit an unsaturated characteristic at more than 3000 Oe magnetic fields, which is due to the competition between the ferromagnetism and the antiferromagnetism of two Fe3+ ions superexchange. These results suggest that optical and magnetic properties of Fe-doped BaTiO3 nanocrystalline films can be changed by Fe composition.
关键词： multiferroics,optical properties,Fe-doped BaTiO3,magnetic properties,chemical solution route
更新于2025-09-23 15:21:21
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Ultra-sensitive method based on time-resolved fluorescence immunoassay for detection of sulfamethazine in raw milk
摘要： A novel lateral flow assay (LFA) was developed by introducing Eu (III)-doped polystyrene nanoparticles (EuNPs) for rapid and ultra-sensitive detection of sulfamethazine (SM2) in raw milk. The limit of detection and linear range of the proposed method were 0.0045 and 0.05–10 ng/mL, respectively. The recovery of LFA for the detection of SM2 in raw milk was 96.1–108.2%. The proposed LFA provides a rapid and convenient strategy for fast and ultra-sensitive screening of SM2 in raw milk. EuNP-LFA may be a remarkable method for the detection of other targets at low concentrations to ensure food safety.
关键词： Lateral flow assay,sulfamethazine,raw milk,Eu (III)-doped polystyrene nanoparticle
更新于2025-09-23 15:21:21
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Design of color tunable thin film polymer solar cells for photovoltaics printing
摘要： Color tunable thin film polymer solar cells have demonstrated the potentials of a wide applications in photovoltaics printing, which is significant for ink pollution reduction and energy saving. This work presents a new effective approach to realize color-tuning photovoltaic cells with optical microcavity structures. Aluminum-doped zinc oxide is utilized as electron transport layer material. With its high electrical conductivity, the thickness tuning range can be quite large, which means the cavity length has a wide variation range. It thus provides sufficient space for optical thin film design to obtain multi colors. By the transfer matrix method, device reflection and absorption spectra are numerically investigated. Based on that, the optical principles for color tunability are explored. In further step, the relationship between device photovoltaics performance and reflective colors are also discussed. Finally, the color coordinates and luminosities are calculated. As results, the colors of the devices designed are capable to cover a relatively large region in Commission Internationale de l′Eclairage (CIE) 1931 x, y chromaticity diagram, which is available to be integrated into the advertisement poster boards, building wall printing and other display applications.
关键词： optical microcavity,thin film polymer solar cells,aluminum-doped zinc oxide,photovoltaics printing,color tunable
更新于2025-09-23 15:21:01
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Effect of PbS quantum dot-doped polysulfide nanofiber gel polymer electrolyte on efficiency enhancement in CdS quantum dot-sensitized TiO2 solar cells
摘要： Quantum dot-sensitized solar cells (QDSSCs) are among the most promising low cost third generation solar cells. Semiconductor quantum dots have unique properties such as high molar extinction coefficients, tunable energy gap by the quantum confinement effect and the ability of multiple exciton generation. In this study, stable CdS QDSSCs were fabricated by using polysulfide liquid electrolytes and also by using cellulose acetate nanofiber-based gel electrolytes. Incorporation of PbS Q dots to the liquid or gel electrolyte showed a significant enhancement in solar cell efficiency. Under the simulated light of 100 mW cm-1 the efficiency of the polysulfide liquid electrolyte based CdS QD solar cells increased from 1.19% to 1.51% and the efficiency of the nanofibre gel electrolyte based CdS QD solar cells increased from 0.94 % to 1.46% due to the incorporation of 5% (wt/wt) PbS Q dots into the respective electrolytes. The efficiency increase has been attributed to the increase in short circuit photocurrent density due to increased sulfide ion (S2-) conductivity evidently caused by indirect ionic dissociation facilitated by PbS QDs.
关键词： Sulfide ion conductivity,Nanofibre gel electrolyte,Efficiency enhancement,Quantum dot sensitized solar cells,Quantum dot doped electrolyte
更新于2025-09-23 15:21:01
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Waveguide optimization and its evaluation of a doped polymer optical ???ber designed for visual detection of stress
摘要： A fiber-optic strain sensor using a fluorophore-doped polymer optical fiber (POF) was fabricated at various waveguiding conditions. The effects attributed to each structural feature of the sensor were characterized by observing the sensor?s response. Two fluorophores, Coumarin 540A and Rhodamine 6G, were used to dope the core and the cladding of a poly(methyl methacrylate)-based POF, respectively. Using doped POFs with different numerical apertures (NAs), the changes in the fluorophore peaks upon the application of stress were analyzed by applying macrobending (s) to the fiber. Although the sensor response did not show linearity with respect to the NA, it was found that the shape of the Coumarin 540A-attributed peak was a factor that represented the sensor?s sensitivity. As a result, the double-cladding structure demonstrated its effectiveness in improving the stress sensitivity.
关键词： double-cladding structure,fluorophore-doped,polymer optical fiber,numerical aperture,fiber-optic strain sensor,stress sensitivity
更新于2025-09-23 15:21:01