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Photodegradation of thiophene over ZrO2–SiO2 nanoparticles: impact of copper decoration on their photocatalytic activity
摘要： A sol–gel technique was useful for the synthesis of zirconia–silica nanoparticles. Metallic copper has decorated zirconia–silica nanoparticles via photo-assisted deposition method, decorated copper mass percent was varied from 0.5, 1.0, 1.5, and 2.0 wt%. XRD results confirm that decoration of zirconia–silica nanoparticles by copper did not alert XRD pattern of zirconia–silica nanoparticles and there are no peaks for copper or copper oxide, due to high dispersion of copper above a surface of zirconia–silica nanoparticles. The decoration of zirconia–silica nanoparticles by copper was reduced band gap energy of zirconia–silica nanoparticles from 3.20 to 2.35 eV with 1.5 wt% Cu decoration. Photocatalytic oxidation of thiophene in presence of visible light was selected to measure the impact of metallic copper on photocatalytic activity of zirconia–silica nanoparticles. 1.5 wt% Cu-decorated zirconia–silica nanoparticles can degrade 100% of thiophene within 90 min.
关键词： ZrO2–SiO2,Sol–gel,Thiophene degradation,Cu decoration,Enhanced photocatalysis,Visible light
更新于2025-11-14 15:26:12
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Erbium-to-dysprosium energy-transfer mechanism and visible luminescence in lead-cadmium-fluorogermanate glass excited at 405?nm
摘要： Erbium-to-dysprosium energy-transfer and visible luminescence in the blue, green, yellow, red, and NIR is reported in PbGeO3:PbF2:CdF2 glass under 405 nm excitation. Absorption and excitation spectra were examined in the UV-VIS-IR spectral region. Emission showed a decrease in the Er3+ emissions around 520 and 545 nm when Dy3+ was added to the host matrix, while the Dy3+ emission around 576 nm (4F9/2 – 6H13/2) increased concomitantly. The recorded lifetime for Er3+ emissions also decreased, as Dy3+ concentration was increased for fixed Er3+ content. No similar behavior was observed when Er3+ concentration varied, confirming a one-way Er3+-to-Dy3+ energy transfer mechanism.
关键词： glass,energy-transfer,visible-light,rare-earth
更新于2025-11-14 15:25:21
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Acid-treated Fe-doped TiO2 as a high performance photocatalyst used for degradation of phenol under visible light irradiation
摘要： The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol–gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.
关键词： Kinetics,Iron doping,Phenol degradation,Visible light,Photocatalyst
更新于2025-11-14 15:25:21
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Impact of doped metals on urea-derived g-C3N4 for photocatalytic degradation of antibiotics: Structure, photoactivity and degradation mechanisms
摘要： Metal doping is an appealing modification strategy of graphitic carbon nitride (g-C3N4) to improve its photocatalytic activity. The interactions of g-C3N4 precursors with metals, however, has often been underappreciated, which can induce great impacts on g-C3N4 formation and properties. Herein, the impacts of metals (Na, K, Ca, Mg) on the morphology, structure, and photoactivity of urea-derived g-C3N4 were investigated. Our TEM and XPS results confirmed that the interactions of doped metals with urea precursors lead to the incorporation of O atoms from urea molecules into the framework of g-C3N4. Due to the synergistic effects of the metals and structural O atoms, doped g-C3N4 performed an elevated photodegradation of antibiotics under the visible light irradiation, which was attributed to the enhanced light-harvesting and reduced charge recombination. In addition, the doped metals presented uneven regulation on the band structures and morphology of g-C3N4. As a result, both superoxide and hydroxyl radicals were generated by g-CN-Na and g-CN-K, whereas, only superoxide radicals were involved in g-CN, g-CN-Ca and g-CN-Mg. Consequently, diversified photodegradation mechanisms for enrofloxacin (ENR) were observed that the g-CN, g-CN-Ca and g-CN-Mg reaction systems mainly attacked the piperazine moiety of ENR while g-CN-Na and g-CN-K provided additional photodegradation pathway by attacking quinolone core of ENR. The present work could provide new insights into further understanding of doping chemistry with g-C3N4.
关键词： Metal doping,Photocatalytic degradation of antibiotics,g-C3N4,Visible light photocatalysis
更新于2025-11-14 15:24:45
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Comparing the Efficiency of N-Doped TiO2 and N-Doped Bi2MoO6 Photo Catalysts for MB and Lignin Photodegradation
摘要： In this study, we tested the efficiency of nitrogen-doped titanium dioxide (N-TiO2) and nitrogen-doped bismuth molybdate (N-Bi2MoO6) compounds as photocatalysts capable of degrading methylene blue and lignin molecules under irradiation with ultraviolet (UV) and visible light (VIS). Moreover, we compared TiO2 and Bi2MoO6 catalysts with N-TiO2 and N-Bi2MoO6 compounds using chemical coprecipitation. The catalysts were prepared starting from Ti(OCH2CH2CH3)4, Bi(NO3)3·5H2O, and (NH4)6Mo7O24 reagents. N-doping was achieved in a continuous reflux system, using ethylene diamine as a nitrogen source. The resulting materials were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, we observed the decrease in particle size after processing the compounds in the reflux system. The results regarding photocatalytic degradation tests show a remarkable effect for nitrogen doped samples, achieving 90% of lignin degradation.
关键词： photocatalysis,lignin,visible light,UV light,bismuth molybdate,Titanium dioxide
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Advanced Technologies for Communications (ATC) - Ho Chi Minh City, Vietnam (2018.10.18-2018.10.20)] 2018 International Conference on Advanced Technologies for Communications (ATC) - Demonstration of A Visible Light Receiver Using Rolling-Shutter Smartphone Camera
摘要： Visible Light Communication (VLC) which has a mass of applications is getting much attention in both academic field and industry. Specifically, light-to-camera (LTC) communications in which information is transmitted to user through visible light signals; whereas, rolling-shutter camera-based receivers are utilized to capture and decode transmitted signals. In this paper, we present a demonstration of LTC communications system which includes a pair of transmitter and receiver. We have used an Arduino Genuino board to implement VLC transmitters which can transmit the identification (ID) messages through light-emitting diodes (LEDs)-based front-ends. At the receiver, we have developed an Android application which utilizes the CMOS image sensor (CIS) of the smartphone camera to receive the light signals. Besides, some practical problems of our LTC prototype and their solutions are also introduced in this paper.
关键词： Optical Camera Communication,Light-to-Camera,Rolling Shutter,Visible Light Communications (VLC)
更新于2025-09-23 15:23:52
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Handling Electromagnetic Radiation beyond Terahertz using Chromophores to Transition from Visible Light to Petahertz Technology
摘要： An increase of the operating frequencies of electromagnetic waves leads from the well-established terahertz technology to the visual and reaches petahertz radiation. It is shown that electromagnetic radiation close to petahertz is attractive for technology where knowledge about radio waves can be applied. The dimensions of such radiation are still classically macroscopic; however, molecular components such as resonators were used where quantum mechanics rules have to be considered. Constructions of coupled resonators for energy transfer are as well demonstrated as molecular components for optical metamaterials.
关键词： Dyes,FRET,Energy transfer,Reflectance,Petahertz,Visible light,Resonators,Metamaterials,Terahertz,Electromagnetic radiation
更新于2025-09-23 15:23:52
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Metal Sulfide Photocatalysis: Visible-Light-Induced Organic Transformations
摘要： Transition-metal sulfides belong to an important subgroup of semiconductor photocatalysts that could promote a variety of valuable redox reactions under mild conditions. One notable merit of metal sulfides is their relatively smaller bandgaps than metal oxides, which in turn make sure that many of them can directly utilize visible light. Historically, the deployment of metal sulfides for visible-light-induced organic transformations took place shortly after the genesis of the research field of heterogeneous photocatalysis. In this review, we primarily focus on recent state-of-the-art advancements of metal sulfide photocatalysis aimed at visible-light-induced selective organic transformations. Interests in this specific branch of photocatalysis have been rekindled due to the new methods for materials synthesis; the pursuit of new mechanisms; or the integration of metal sulfides with metal oxides, metal nanoparticles or other emerging materials. Thus we categorize them into four sections according to the different strategies in developing novel or more efficient organic processes. Binary and ternary metal sulfides, usually associated with new materials synthesis and mechanistic insights, can be used directly for visible-light-induced organic transformations. This is the basis of other further developments and will be introduced firstly. Next, the cooperation between metal sulfides and metal oxides or metal nanoparticles can be conducive to many photocatalytic systems. These developments will be discussed in the next two ensuing sections. Furthermore, the integration of metal sulfides with recent developed emerging materials such as metal-organic frameworks (MOFs), graphene and graphitic carbon nitride (g-C3N4) would be discussed in another section to highlight the importance of merging metal sulfides with these materials. We attempt to keep an impartial panorama of these four distinctive sections even though the phases of development are quite different among sections, leaving plenty of room for the future expansion of this burgeoning area.
关键词： Metal Sulfide,Selective Oxidation,Photocatalysis,Visible Light,Selective Reduction
更新于2025-09-23 15:23:52
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The Use of Magnetic Orientation as a Pinning Modality for Investigation of Photon-Magnon Interactions in Magnetic Nanoparticle Systems
摘要： In this work, an experimental setup to study the dependence of a visible-light transmission through a magnetic granular film on the magnetic field direction was presented. The results measured the transmission (T) of the visible light, with the wavelengths (λ) were in the range from 560 to 695 nm, by the magnetic nanogranular films Cox-(Al2O3)100-x system, with Co compositions are x = 10 ÷ 45 at.%, as a function of the magnetic field direction were reported. These investigations were carried out under an external magnetic field of H = 400 Oe, which directs to the normal of the sample surface by an angle varied in the range of θ = 0° ÷ 45°, to magnetize the magnetization direction of all the Co particles following this direction. Consequently, the angle θ between the magnetization direction with the incident-light direction, which sets as the optical axis of the system and always keeps fixedly to the normal of the sample surface, is established. The experimental results showed the different dependencies of T on the angle θ, the magnetic field H, the Co composition x, and the wavelength λ. These dependencies attributed to a behavior that relates to so-called photon-magnon interaction.
关键词： Ferromagnetic Nanoparticle (FMNP),Visible-Light Transmission,Magnetic Nanogranular Film (MNGF),Plasmonic Spin,Photon-Magnon Interaction
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Advanced Technologies for Communications (ATC) - Ho Chi Minh City, Vietnam (2018.10.18-2018.10.20)] 2018 International Conference on Advanced Technologies for Communications (ATC) - Keynote talk #2: Visible light communications for 5G-and-beyond wireless telecommunications networks
摘要： Artificial general lighting sources are currently evolving through the traditional fluorescent and incandescent sources to the modern energy saving light bulbs and now white light emitting diodes (LEDs). This trend has been spurred on through global awareness of the necessity for reducing the size of our carbon footprint. The introduction of solid state LED lighting has attracted the attention of communications engineer's worldwide, enabling the achievement of the dual functionality of room illumination whilst simultaneously transmitting wireless data via visible light communication (VLC), or Light Fidelity (LiFi), in optical spectrum regime. Although the existing wireless networks are primely dominated by radio-based technology, the emerging VLC will play increasingly important role in future wireless telecommunications landscape. It is anticipated that both spectrum regimes, radio and optical, will eventually contribute equally for the next network generation, especially in nanocell and picocell network structures. This talk will outline the growth of optical wireless communications including VLC, and present the challenges and roadmap of the technology for the future generation of wireless networks.
关键词： Visible Light Communications,Networks,LED,LiFi
更新于2025-09-23 15:23:52