- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Preparation of size-controlled silver phosphate catalysts and their enhanced photocatalysis performance via synergetic effect with MWCNTs and PANI
摘要： In this work, novel photocatalysts Ag3PO4@MWCNTs@PANI with excellent visible light photocatalytic performance and photostability were successfully prepared by a facile in-situ precipitation method. The optimal catalyst Ag3PO4@0.1%MWCNTs@3%PANI showed the highest photocatalytic performance for degradation of phenol and p-nitrophenol, the apparent rate constant of which was 21.9 and 10 times than that of the pure Ag3PO4, respectively. Interestingly, the Ag3PO4 exhibited significant changes in particle size, which changed from 10-20 μm for pure Ag3PO4 particles into 0.38-1.0 μm and 0.15-0.38 μm with the addition of MWCNTs and PANI, respectively. In presence of MWCNTs, similar phenomena have been reported in our previous studies, while the ability of PANI dissolved in the presence of DMF solvent to control the size of Ag3PO4 crystal was reported for the first time. The dramatic enhancement of photocatalytic activity and photostability could be attributed to the synergetic effect between MWCNTs and PANI on Ag3PO4. The MWCNTs penetrating in the bulk phase of Ag3PO4 could serve as conductors of photogenerated electrons and rapidly migrated electrons to the surface of the photocatalysts. Meanwhile, photogenerated holes in the valence band of Ag3PO4 were transferred to the photocatalysts surface through HOMO of PANI. Consequently, high separation efficiency of electron-hole pairs was successfully achieved. A novel design and preparation strategy for photocatalyst was proposed to simultaneously achieve the small size control of catalyst crystal and improve the photocatalytic performance of catalyst by adding MWCNT and PANI.
关键词： MWCNTs,PANI,size-controlled,visible light catalyst,photocatalysis
更新于2025-09-04 15:30:14
-
Review on Li-Fi: an advancement in wireless network communication with the application of solar power
摘要： Light Fidelity, commonly referred to as Li-Fi is a technology that was introduced by a German physicist called Herald Hass. This technology in its own uniqueness considers the use of light (Light Emitting Diode, LED to be specific) as its medium of delivering high speed communication that complies with standard IEEE 802.15.7 bidirectional communication standard. This optical means of communications is also known as visible light communication. It is safer when compared with Wi-Fi network. This paper will focus on Li-Fi applications, comparison with existing technologies like Wi-Fi and the inclusion of an alternative source of power i.e., solar power, as a means of effectively optimizing on the availability and accessibility of the benefits in places where erratic or total power outage is a common trend.
关键词： solar power,Visible Light Communication (VLC),Li-Fi,Wi-Fi
更新于2025-09-04 15:30:14
-
Synthesis of yttrium doped BiOF/RGO composite for visible light: Photocatalytic applications
摘要： In this present work, yttrium doped bismuth oxy fluoride/reduced graphene oxide (Y-BiOF/RGO) composite was synthesized using a simple solvothermal method. As synthesized composite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The photocatalytic property was evaluated towards the degradation of methylene blue (MB) dye under the visible-light irradiation. The characterization results highlighted that the efficient incorporation of both yttrium ions and RGO greatly reduced the recombination rate of BiOF and extended the visible-light absorption ability. As synergistic effects, the prepared Y-BiOF/RGO composite exhibited maximum degradation rate of 98% in 360 min, which is 6.5 times higher than pure BiOF. The clear mechanism for the enhanced photo-activity by Y-BiOF/RGO was discussed.
关键词： Semiconductors,BiOF,Photocatalysts,Yttrium,Graphene,Visible light
更新于2025-09-04 15:30:14
-
Synthesis of Lead-Doped SrTiO <sub/>3</sub> Perovskite Type Oxides and Their Photocatalytic Activity Under Visible Light Irradiation
摘要： Pure and lead-doped SrTiO3 perovskite type oxides were successfully synthesized by sol–gel method and characterized by XRD, SEM and DRS. From the results of XRD, the metal replacement with the Pb ion on the crystal lattice does not change the high crystallinity of the perovskite structure. UV-vis DRS analysis shows that Pb was in situ doped in the lattice of SrTiO3 and the absorption band shifted to a higher wavelength on the Pb-doped SrTiO3 sample compared to the pure SrTiO3 sample. We also investigated the photocatalytic activity of Pb-doped SrTiO3 for the decomposition of Rhodamine B under visible light irradiation. From the results of photocatalytic decomposition of RhB, a doping of lead into SrTiO3 perovskite oxides enhanced the photocatalytic activity under visible light irradiation.
关键词： Photocatalytic Activity,Visible Light Irradiation,Lead-Doped SrTiO3
更新于2025-09-04 15:30:14
-
Chaos Synchronization in Visible Light Communications with Variable Delays Induced by Multipath Fading
摘要： Visible Light Communication (VLC) uses light-emitting diodes to provide wireless connectivity in public environments. Transmission security in this emerging channel is not trivial. Chaotic modulation techniques can provide encryption directly in the physical layer based on the random-alike evolution and strong synchronization prospect given by deterministic chaos. In secure chaotic inclusion or embedding methods, continuous-time chaos oscillator models need to be synchronized via a coupling carrier. Here we present a ?rst numerical simulation study for the impact of the variable delays induced by line-of-sight and non-line-of-sight multipath fading in complete chaotic synchronization. More precisely, we analyze a chaotic Colpitts oscillator that is simultaneously transmitting the carrier to several mobile receivers via nine spotlights. Such induced delays depend on both the receiver position and the carrier frequency, in?uencing the complete synchronization required in modulation via chaotic inclusion. Correlation values for several receiver positions and carrier frequencies are presented, examining the progressive emergence of the multipath effect and its impact on chaotic synchronization. We show that, for the chaotic oscillator and coupling applied in the de?ned room settings, complete chaotic synchronization can be achieved and that it is robust up to the tens of MHz region.
关键词： multipath channels,network security,chaotic communication,visible light communication,nonlinear systems,chaos synchronization
更新于2025-09-04 15:30:14
-
Fabrication of highly efficient and hierarchical CdS QDs/CQDs/H-TiO2 ternary heterojunction: Surpassable photocatalysis under sun-like illumination
摘要： Highly efficient and durable visible-light utilized nanocomposites have a vital role in environmental pollutants remediation. Hence, in this study, we have fabricated CdS QDs co-sensitized CQDs/H-TiO2 (Hollow Titania) ternary heterostructures (CdS QDs/CQDs/H-TiO2) in a facile region-selective deposition route. The as-fabricated nanocomposites were evidently characterized by physicochemical techniques. CdS QDs were uniformly distributed on the smooth surface of hierarchical CQDs/H-TiO2 heterojunction. The as-fabricated CdS QDs/CQDs/H-TiO2 nanocomposite has high-performances for efficient degradation efficacy of phenol, MB and RhB which exhibited enhanced degradation activities with rate constants (k) of 0.03, 0.051 and 0.045 min-1, respectively. All these superior photocatalytic activities obviously attributed to the effect of calcination temperature, enhanced photocurrent, minimized recombination of photo-induced charges in the photocatalysis and optimum content of CdS QDs have the distinct basis for the close interfacial connection developing. In addition, evidenced on the arguable results of electron spin resonance and radical-trapping experiments, the primary reactive-oxygen species and a plausible reaction-mechanism for organic pollutants degradation over CdS QDs/CQDs/H-TiO2 were proposed. This creative work is strategically considered an important step to potentially enhance the utilization of TiO2 in various fields as visible light-induced heterojunction.
关键词： Hollow TiO2,CdS QDs/CQDs/H-TiO2,Visible-light photocatalysis,CQDs/H-TiO2,Environmental remediation
更新于2025-09-04 15:30:14
-
Fabrication of Perylene Tetracarboxylic Diimide-Graphitic Carbon Nitride Heterojunction Photocatalyst for Efficient Degradation of Aqueous Organic Pollutants
摘要： Metal-free g-C3N4 is the promising candidate for the next generation visible light-responsive photocatalyst, however, high recombination probability of the photogenerated charge carriers on g-C3N4 limits its photocatalytic activity. To further increase the intrinsic photocatalytic activity of g-C3N4, here perylene tetracarboxylic diimide-g-C3N4 heterojunctions (PDI/GCN) are prepared by one-step imidization reaction between perylene tetracarboxylic dianhydride (PTCDA) and g-C3N4 in aqueous solution. By the combination of various testing results it is confirmed that the surface hybridization of PTCDA and g-C3N4 in the PDI/GCN heterojunctions via O=C?N?C=O covalent bonds occurs at lower PTCDA-to-g-C3N4 weight percentage. By selecting p-nitrophenol and levofloxacin as the target organic pollutants, the visible light photocatalytic performance of the PDI/GCN heterojunctions are studied. It shows that the PDI/GCN heterojunction prepared at PTCDA-to-g-C3N4 weight percentage of 1% exhibits remarkably higher visible light photocatalytic degradation and mineralization ability towards aqueous target pollutants as compared with g-C3N4 and Degussa P25 TiO2. On the basis of the experimental results including photoelectrochemistry, indirect chemical probe and electron spin resonance spectroscopy it is verified that the surface hybridization in the heterojunctions is responsible for this enhanced photocatalytic activity via accelerating the migration and separation of the photogenerated charge carriers, causing to produce more active species like ?O2?, hVB+ and ?OH for deep oxidation of PNP or LEV to CO2 and inorganic anions.
关键词： graphitic carbon nitride,heterojunction,perylene tetracarboxylic diimide,visible light photocatalysis,organic pollutant
更新于2025-09-04 15:30:14
-
[IEEE 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN) - Nantes (2018.9.24-2018.9.27)] 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN) - Indoor Positioning Using OFDM-Based Visible Light Communication System
摘要： Precise indoor positioning is essential to support emerging applications of location aware mobile computing. Current positioning techniques that use signals transmitted in the Gigahertz region of radio-frequency spectrum do not provide highly accurate position estimates due to multipath propagation of signals. This paper proposes a novel positioning system which uses the entities of visible light communication (VLC) system as anchors and tags. Our technique scales with the number of tags and the VLC network provides both positioning and communication capabilities. The anchor points transmit the OFDM-based VLC signals synchronously, and we estimate the time differences of arrival between anchor points and tags using positioning reference signals embedded into the air-interface of the VLC system. Simulation results show that positioning accuracy of 10 cm or better is possible for over 95% of users if the sampling clock offset is better that 10 ppm, clock jitter is below 1 ps, and a bit resolution of at least 16 bits is available.
关键词： multipath propagation,OFDM,TDOA,visible light communication,indoor positioning
更新于2025-09-04 15:30:14
-
Semiconductor Heterojunctions for Enhanced Visible Light Photocatalytic H2 Production
摘要： Semiconductor-based heterojunctions have been shown to be effective photocatalytic materials to overcome the drawbacks of low photocatalytic efficiency that results from a high rate of electron?hole recombination and narrow photo-response range. In this paper, we report on the study of heterojunctions made from visible light active, graphitic carbon nitride, g-C3N4), and UV light active, strontium pyroniobate, Sr2Nb2O7. Heterojunctions made from a combination of g-C3N4 and nitrogen-doped Sr2Nb2O7 obtained at different temperatures were also studied to determine the effect of N doping. The photocatalytic performance was evaluated by using photocatalytic hydrogen evolution reaction (HER)from water g under visible light irradiation. It was found that the photocatalytic activities of as prepared heterojunctions are significantly higher than that of individual components under similar conditions. Heterojunction formed from g-C3N4 and N-doped Sr2Nb2O7 at 700oC (CN/SNON-700) showed better performance than heterojunction made from g-C3N4 and Sr2Nb2O7 (CN/SNO). A plausible mechanism for the heterojunction enhanced photocatalytic activity is proposed based on, relative band positions, and photoluminescence data.
关键词： graphitic carbon nitride,visible light photocatalysis,strontium pyroniobate,Semiconductor heterojunctions,hydrogen production
更新于2025-09-04 15:30:14
-
Molecular motors with high quantum efficiency and visible-light responsiveness: Meeting two challenges in one design
摘要： The development of light-driven rotary molecular motors is guided by a number of key goals regarding performance and applicability. While a variety of approaches to achieve high quantum yields for small UV-driven motors have been discovered, such as incorporating a protonated or alkylated nitrogen Schiff base, less progress has been made toward the goal to power molecular motors with nondestructive visible light, which will facilitate their future usage in radiation-sensitive environments. Here, we present non-adiabatic molecular dynamics simulations based on multiconfigurational quantum chemistry to demonstrate that Schiff-base motors can maintain high quantum yields also when their conjugated systems are sufficiently large for them to rather be driven by visible light. In particular, we show that a visible-light responsive Schiff-base motor featuring dihydropyridinium and cyclopentenylidene motifs achieves quantum yields of almost 70% for each of the two photoisomerizations that underlie its rotary motion.
关键词： Molecular devices,Quantum yield,Rotary motion,Molecular dynamics,Visible light
更新于2025-09-04 15:30:14