- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- Carbon nanotubes
- Magnetic focused
- Field emission cathodes
- Travelling wave tubes
- Heat Trap
- outgassing
- lifetime
- current stability
- cathode
- thermionic emission
- Electronic Science and Technology
- Nanomaterials and Technology
- University of British Columbia
- Beijing Vacuum Electronics Research Institute
- Sun Yat-sen University
-
Spectroelectrochemical operando method for monitoring a phenothiazine electrografting process on amide functionalized C-nanodots/Au hybrid electrodes
摘要： Phenothiazine derivatives are extensively explored dye molecules, which present interesting electrochemical and optical properties. In recent years, the possibility of transforming some phenothiazines in their aryl diazonium salt derivatives has been proved, what allows them to be electrochemically reduced and electrografted onto conductive surfaces. This is a smart way to modify these surfaces and enable them with specific functionalities. In order to better comprehend the electrografting process and consequently have a higher control of it, in this work we have carried out an exhaustive study by operando UV–Vis spectroelectrochemistry of the electrografting of a phenothiazine aryl diazonium salt onto amide carbon nanodots. As a model of phenothiazine dye we have chosen Azure A. The electrografting onto carbon nanodots has been stablished by comparison with the results obtained on bare gold electrodes in this novel study. The presence of carbon dots improves the reversibility of the electrochemical process as derived from the results obtained by operando UV–Vis spectroelectrochemistry. In addition, to asses that the electrochemical process studied corresponds to the electrografting, the results have been compared to those obtained for the simple Azure A adsorption. This study shows the advantages of obtaining simultaneously the electrochemical and the spectroscopic evolution of an electron-transfer process in a single experiment, in a particular electrochemical reaction. This work could be the starting point for the study of the electrografting on other nanomaterials.
关键词： Azure A,Electrografting,Diazonium salt,Carbon nanodots,Spectroelectrochemistry
更新于2025-09-23 15:22:29
-
Layered Double Hydroxides Decorated Graphic Carbon Nitride Film as Efficient Photoanodes for Photoelectrochemical Water Splitting
摘要： In the present work, we investigate the graphic carbon nitride (g-CN) film as photoanode to catalyze the photoelectrochemical (PEC) water oxidation and study the influence of NiCo layered double hydroxides (NiCo-LDH) layer on the performance. The g-CN film with good quality and intimate contact with substrate was in-situ prepared via solvothermal process and subsequent calcination. NiCo-LDH is further decorated on the g-CN film through cathodic electrochemical deposition to work as co-catalyst. The g-CN/NiCo-LDH composite with optimized NiCo-LDH loading amount exhibits a photocurrent of 11.8 μA cm-2 at 0.6 V vs. SCE, which is 2.8 times of bare g-CN. Characterizations and performance tests demonstrate that NiCo-LDH promoted reaction kinetics and charge separation. The results provide an effective strategy to improve the photoelectrochemical water oxidation performance of g-CN through NiCo-LDH co-catalyst. This work to investigate the photoelectrochemical water oxidation is of great significance toward explore the overall water splitting on the g-CN film.
关键词： Layered double hydroxides,Solvothermal process,Photoelectrochemical water oxidation,Co-catalyst,Graphitic carbon nitride
更新于2025-09-23 15:22:29
-
Synthesis of multifunctional photocatalyst vanadium oxide/activated carbon via in situ utilization of stone coal ore
摘要： In this work, activated carbon (AC), vanadium oxide (V2O5), and V2O5/AC photocatalyst were prepared by in situ utilization of stone coal ore for the first time. The synthesis conditions for activated carbon (AC) and V2O5/AC were thoroughly investigated via orthogonal experiments and single factor experiments, respectively. The obtained optimal parameters could be directly adopted in practical application about utilization of stone coal ore. The optimal deashing experimental parameters for stone coal ore were: HF concentration of 15%, H2SO4 concentration of 15%, acid leaching temperature of 85 °C, and acid leaching time of 2 h. The as-prepared activated carbon from stone coal ore could be applied to the removal of methylene blue. The as-prepared V2O5/AC photocatalyst possessed a highly visible-light-driven photocatalytic activity for the removal of Rhodamine B (RhB) dye. The RhB degradation ratio could reach to 90.0% after only 3 h photocatalytic reaction. This photocatalyst would be possibly applied to treatment other organic dye wastewater. Actually, this work would extend the application field of stone coal ore. Most importantly, we hope the proposed new concept that in situ utilization of ore can be widely spread and applied.
关键词： Stone coal ore,Photocatalyst,V2O5,Activated carbon,In situ utilization
更新于2025-09-23 15:22:29
-
Photocatalytic hydrogen evolution assisted by aqueous (waste)biomass under simulated solar light: Oxidized g-C3N4 vs. P25 titanium dioxide
摘要： Oxidized graphitic carbon nitride (o-g-C3N4) and Evonik AEROXIDE? P25 TiO2 were compared for lab-scale photocatalytic H2 evolution from aqueous sacrificial biomass-derivatives, under simulated solar light. Experiments in aqueous starch using Pt or Cu–Ni as the co-catalysts indicated that H2 production is affected by co-catalyst type and loading, with the greatest hydrogen evolution rates (HER) up to 453 and 806 μmol g?1 h?1 using TiO2 coupled with 3 wt% Cu–Ni or 0.5 wt% Pt, respectively. Despite the lower surface area, o-g-C3N4 gave HERs up to 168 and 593 μmol g?1 h?1 coupled with 3 wt% Cu–Ni or 3 wt% Pt. From mono- and di-saccharide solutions, H2 evolution was in the range 504–1170 μmol g?1 h?1 for Pt/TiO2 and 339–912 μmol g?1 h?1 for Cu–Ni/TiO2, respectively; o-g-C3N4 was efficient as well, providing HERs of 90–610 μmol g?1 h?1. The semiconductors were tested in sugar-rich wastewaters obtaining HERs up to 286 μmol g?1 h?1. Although HERs were lower compared to Pt/TiO2, a cheap, eco-friendly and non-nanometric catalyst such as o-g-C3N4, coupled to non-noble metals, provided a more sustainable H2 evolution.
关键词： Biomass,Graphitic carbon nitride,Hydrogen,Photocatalysis,Solar light,Titanium dioxide
更新于2025-09-23 15:22:29
-
Enhanced photocatalytic activity of hierarchical titanium dioxide microspheres with combining carbon nanotubes as “e-bridge”
摘要： Enhancing photocatalytic activity of titanium dioxide (TiO2) by efficient charge separation is essential but challenging. Herein, the recombination between photo-generated e–-h+ pairs is effectively hindered owing to the “e-bridge” formed between hierarchical TiO2 microspheres and carbon nanotubes (CNTs). The as-prepared three-dimensional TiO2 microspheres covered by intercrossing lamellar crystals are abundant in pores and sharp edges, forming an ideal interface with large surface area and numerous active sites for photocatalysis. Combined with CNTs, the TiO2 microspheres are connected and stabilized. Moreover, the CNTs serve as pathways for electrons, benefiting the effective separation of e–-h+ pairs and accounting for the superior photocatalytic activity. Transient fluorescence spectra shows that the lifetime of electrons on TiO2 prolongs from 5.23 ns to 10.14 ns assisted by CNTs. In aqueous matrix, electrons gathering on the CNTs can react with O2 to produce O2–, and simultaneously, plenty of holes left in TiO2 host generate OH by oxidizing adsorbed H2O, producing abundant active species for photocatalytic degradation of 4-nitrophenol. The highest degradation efficiency in removing organic contaminants is achieved on TiO2@CNTs hybridized with CNTs weight ratio being 5%.
关键词： e-Bridge,Titanium dioxide,Carbon nanotubes,Organic pollutant,Photocatalytic degradation
更新于2025-09-23 15:22:29
-
Non-destructive defect evaluation of polymer composites via thermographic data analysis: A manifold learning method
摘要： Recently, various thermographic data analysis methods have been utilized in the field of non-destructive evaluation (NDE) to process thermal images and enhance the visibility of defects. However, most of them extract only linear features, leading to cumbersome results. In this work, manifold learning is introduced into the thermographic data analysis field. As a nonlinear dimensionality reduction technique, manifold learning can identify an intrinsically low-dimensional manifold in a high-dimensional data space. Specifically, an isometric feature mapping (ISOMAP) based manifold learning thermography (MLT) method is proposed to analyze the thermographic data, which can effectively distinguish the uneven background, noise, and defect characteristics contained in thermal images and make the defect detection easier. The feasibility of MLT is illustrated using a carbon fiber-reinforced polymer (CFRP) specimen. The results show that, comparing to the conventional linear methods, the present method can better determine the defect information, including the positions, sizes, and shapes.
关键词： Thermographic data analysis,Non-destructive evaluation,Manifold learning,Active infrared thermography,Carbon fiber-reinforced polymer
更新于2025-09-23 15:22:29
-
Functionalized fluorescent carbon nanoparticles for sensitively targeted of folate-receptor-positive cancer cells
摘要： The folic acid-functionalized fluorescent carbon dots (FA-CDs) was synthesized via the assembly of FA to the surface of CDs. A facile hydrothermal method with proline and ethylenediamine as precursors was used to fabricate CDs. The as-prepared CDs possessed active amino groups where the CDs could be further engineered for the conjugation with FA. The uptake of the as-synthesized FA-CDs by FR positive MCF-7 cells (FR++) and HepG-2 cells (FR+) via receptor-mediated endocytosis was demonstrated by confocal laser scanning microscopy, which is further verified by a comparative study with FR-negative PC-12 cells (FR-). The bright fluorescence can be observed in FR positive MCF-7 cells while negligible fluorescence was observed in PC-12 cells with low-expressed FR, demonstrating that FA-CDs could accurately identify FR-positive cancer cells from normal cells. The FA-CDs shared favorable biocompatibility, excellent optical properties and ultra-low toxicity etc. Holding these superior properties, the FA-CDs was implemented as a highly effective platform for biological labeling and imaging, which may provide a innovative vision for cancer diagnosis and succeeding personalized therapy.
关键词： Folic acid-functionalized,Targeted bioimaging,Cancer cells,Carbon dots
更新于2025-09-23 15:22:29
-
A convenient green method to synthesize luminescent carbon dots from edible carrot and its application in bioimaging and preparation of nanocatalyst
摘要： A simple single-stage method, based on refluxing edible carrot with aqueous trisodium phosphate (TSP) has been reported to synthesize blue color luminescent carbon dots (CDs). Transmission electron microscopy (TEM) image showed that CDs are almost spherical in shape and the size is around 3-8 nm. Fourier-transform-infrared (FTIR) and 1H-NMR spectroscopy study revealed that the carbohydrates present in the carrot undergone carbonization to produce luminescent CDs. Optimization study indicate that refluxing 5 g of carrot in 80 mM TSP aqueous solution for 120 min is adequate to produce highly luminescent blue CDs. The CDs produced are used as luminophore to image bacteria through fluorescence microscopy. CDs have membrane good permeability and minimum toxicity against Gram-negative and Gram-positive bacteria. The CDs capability for direct reduction of silver ions to elemental silver (Ag0) and gold ions to elemental gold (Au0) without additional reducing and stabilizing agent was demonstrated. The resulting Ag and Au nanoparticles have a size of 8-22 nm and 5-15 nm, respectively. The catalytic activity of nanoparticles in the hydrogenation reaction was investigated. The results suggest that the nanoparticles had high catalytic activity in the sodium borohydride mediated hydrogenation of nitroaromatic compounds.
关键词： nanoparticles,bioimaging,carrot,trisodium phosphate,nanocatalyst,Carbon dots
更新于2025-09-23 15:22:29
-
Tuning of carbon dots emission color for sensing of Fe3+ ion and bioimaging applications
摘要： Herein, we report a facile one-step synthetic strategy for fabrication of three (blue, green and yellow) fluorescent color carbon dots (CDs) from tomato (Solanum lycopersicum). The as-synthesized CDs showed emission peaks at 450, 520 and 560 nm for blue, green and yellow color CDs when excited at 370, 420 and 460 nm, respectively. Using tomato as a carbon source, the fabricated three fluorescent color CDs showed good water dispersity and high quantum yield. The analytical performances of three fluorescent color CDs are evaluated by detecting Fe3+ ion in biofluids and iron tablets. Upon the addition of Fe3+ ion under optimal conditions, the fluorescence intensity of three fluorescent color CDs was quenched linearly over the range of 0.1 to 2.0 μM. This method opens a new analytical strategy to quantify Fe3+ ion in iron tablets and biofluids with high sensitivity. Further, the uptake of three fluorescent color CDs into HeLa cells was confirmed by confocal laser scanning microscopy. Intracellular experiments demonstrated that the three fluorescent color CDs were effectively internalized the cells and show excellent biocompatibility and low toxicity, suggesting that the CDs can be used as good candidates for biomedical applications.
关键词： Fluorescent carbon dots,Fe3+ ion,Cancer cells,Fluorescence spectroscopy and microscopy,Tomato
更新于2025-09-23 15:22:29
-
A far-red FRET fluorescent probe for ratiometric detection of l-cysteine based on carbon dots and N-acetyl-l-cysteine-capped gold nanoparticles
摘要： A novel far-red fluorescence resonance energy transfer (FRET) fluorescenct probe for ratiometric detection of L-cysteine (L-Cys) has been designed. The system was established a FRET assembly by positively charged carbon dots (CDs) and negatively charged N-acetyl-L-cysteine capped gold nanoparticles (NAC-AuNPs). The fluorescence of CDs at 539 nm could be effectively quenched in the presence of NAC-AuNPs owing to FRET process, while the emission of NAC-AuNPs at 630 nm was appeared. Subsequently, the interactions between L-Cys and NAC-AuNPs resulted in the decreased emission intensity of NAC-AuNPs, but the emission intensity of CDs kept almost constant due to the continuous FRET efficiency. The ratio of emission intensities at 539 and 630 nm (I539/I630) exhibited a linear correlation to the L-Cys concentration in the range of 1.0-110 μM with the detection limit of 0.16 μM. Moreover, this far-red ratiometric sensor also revealed excellent selectivity toward L-Cys over other amino acids, which showed very high potential in the practical application for diagnosing of cysteine-related disease.
关键词： Fluorescence resonance energy transfer,gold nanoparticles,L-cysteine,Carbon dots
更新于2025-09-23 15:22:29