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One step to prepare CNTs modified porous g-C3N4 with excellent visible-light photocatalytic performance
摘要： A kind of carbon nanotubes (CNTs) modified porous graphitic carbon nitride (CNTs/pg-C3N4) photocatalyst was successfully synthesized via one step thermal polycondensation and completely measured by some instruments, such as XRD, FTIR, TEM, BET, DRS, PL, etc. And the relevant experimental data indicated that loaded CNTs could be beneficial to the photoinduced charges transfer, facilitating photoinduced charge separation rate. Meanwhile, surface area and visible light adsorption of CNTs/pg-C3N4 photocatalyst could be increased and improved. These synergetic effects resulted in the as-synthesized CNTs/pg-C3N4 photocatalyst exhibiting better visible-light-induced photocatalytic performance for organic pollutant degradation and the product of clean energy than bulk g-C3N4, pg-C3N4 and CNTs modified bulk g-C3N4, and excellent stable photocatalytic performance was also observed after several recycling experiments. Finally, a reasonable improved photocatalytic reaction mechanism for CNTs/pg-C3N4 photocatalyst is presented.
关键词： Porous graphitic carbon nitride,Photocatalytic performance,Carbon nanotubes,Photocatalyst,Visible-light
更新于2025-09-10 09:29:36
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Tunable Type I and II heterojunction of CoOx nanoparticles confined in g-C3N4 nanotubes for photocatalytic hydrogen production
摘要： This work reports tunable heterojunction architectures of cobalt oxides (CoOx) nanoparticles confined on well-arrayed graphitic carbon nitride nanotubes (C3N4 NTs) by using a facile one-pot method but under different annealing atmospheres. A Type II heterojunction of cobalt monoxide nanoparticles (CoO NPs)/C3N4 NTs was obtained after annealing under vacuum, and fine CoO NPs less than 8 nm in size were homogeneously anchored on the surface of C3N4 NTs. A Type I heterojunction of tricobalt tetraoxide (Co3O4)/C3N4 NTs were formed under air condition, and Co3O4 NPs in the size range of 20 to 80 nm were aggregated on the surface. The photocatalytic activities of these two heterojunctions were evaluated with hydrogen production from water splitting. The strategically developed CoO/C3N4 NTs with a 7 wt. % CoO shows the highest H2 yield under visible light irradiation and the best stability among the photocatalysts studied in this work. Comprehensive characterization results reveal that the superior performance of CoO/C3N4 NTs may be attributed to the uniformly distributed smaller nanoparticles on the well-arrayed nanotubes, the longer lifetime of excited electrons, the faster charge transfer and the stronger electronic interaction between the heterojunctions. Our Kelvin probe force microscopy results firmly verify that the CoO/C3N4 NT and Co3O4/C3N4 NT nanocomposites form a Type II and Type I heterojunction, respectively, and charge transfer pathways and reaction mechanisms are therefore established.
关键词： hydrogen production,carbon nitride nanotubes,tricobalt tetraoxide,Heterojunction architectures,cobalt monoxide
更新于2025-09-10 09:29:36
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First Principle Study on Optical Properties of Tri-Group Doped (6,6) SiC Nanotubes
摘要： The optical properties of tri-group (B, Al, Ga, In) doped (6,6) SiC nanotubes (SiCNTs) are studied from first principles. The results show that the main absorption and dispersion of SiCNTs caused by the intrinsic transition appear in the ultraviolet-visible region (below 500 nm), and the tri-group doping increases the minimum dielectric constant value resulting in enhanced transmittance. In addition, the tri-group doping can introduce a weak absorption and dispersion region in the near-mid-infrared region, and the response peak blue shifts as the diameter of the doping atom increases. Comparative studies of reflectance, absorptivity, and transmittance show that the key factors affecting the transmittance of SiCNTs are reflectance (or refractive index) rather than absorption coefficient.
关键词： ultraviolet-visible region,SiC nanotubes,near-mid-infrared region,tri-group doped,optical properties,first principles,transmittance
更新于2025-09-10 09:29:36
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A field emission performance test device for continuous adjustment of the electrode spacing in the vacuum system
摘要： This work presents a device that can adjust electrode spacing inside a vacuum system to evaluate the field emission characteristics of the carbon nanotube array cathode grown on a stainless steel substrate. It was made by coaxial connection of the rear end of a screw micrometer, which acts as the anode, with a stepper motor. The distance between the anode and the cathode was controlled by altering the pitch of the stepper motor with an angle precision of 1 degree. Therefore, the electrode separation can be tuned in the range of 0～15mm, at 1.388μm incremental steps. Comparing with devices with a fixed electrode spacing, the advantage is that this device allows continuous regulation of the electrode spacing after it is placed in a vacuum system to test the emission properties under various electrical parameters in one process thus avoiding repeated breaking of the vacuum environment. Therefore, test efficiency is improved, hence saving manpower, material resources, testing time and greatly reducing the cost of experimentation. This device is simple in structure and relatively easy to prepare.
关键词： Movable anode,Field emission,Carbon nanotubes,Vacuum system,Continuous regulation,Spiral micrometer
更新于2025-09-10 09:29:36
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission characteristics of CNT film emitters according to emission tip shapes
摘要： We fabricated carbon nanotube (CNT) field emitters using a CNT film, which indicated the point-type CNT film emitter, and evaluate field emission properties of the CNT field emitter in the triode configuration. The CNT film emitters showed good emission properties such as the low turn-on field, the high emission current and emission stability. We also investigated field emission properties of the CNT film emitter by adjusting the angle of tip of the CNT film.
关键词： field emission,triode structure,point-type field emitter,Carbon nanotubes field emitter
更新于2025-09-10 09:29:36
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Photocurrent enhancement on TiO2 nanotubes co-modified by N+ implantation and combustion of graphene
摘要： Nitrogen ions doped TiO2 nanotubes (N-TNTs) were synthesized via ion implantation and anodization. Graphene was deposited on the surface of N-TNTs during anodization. After being annealed at the temperature of 450 °C, the samples were determined using FE-SEM, XRD, XPS, and UV-Vis DRS. The photoelectric performance of the samples was confirmed by transient photocurrent. The results indicated that morphology and structure of N-TNTs were improved due to ion implantation. Because of the combustion of deposited graphene during the annealing process, the degree of crystallinity of N-TNTs was improved, and the contents of substitutional N increased. The TNTs modified by ion implantation and combustion of graphene exhibited the best photoelectric performance.
关键词： Visible light,TiO2 nanotubes,Carbon materials,Ion beam technology,Photoelectric properties
更新于2025-09-10 09:29:36
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Impact of the anodization time on the photocatalytic activity of TiO <sub/>2</sub> nanotubes
摘要： Titanium oxide nanotubes (TNTs) were anodically grown in ethylene glycol electrolyte. The influence of the anodization time on their physicochemical and photoelectrochemical properties was evaluated. Concomitant with the anodization time, the NT length, fluorine content, and capacitance of the space charge region increased, affecting the opto-electronic properties (bandgap, bathochromic shift, band-edge position) and surface hydrophilicity of TiO2 NTs. These properties are at the origin of the photocatalytic activity (PCA), as proved with the photooxidation of methylene blue.
关键词： nanotubes,photocatalytic activity,photoelectrochemistry,titanium(IV) oxide (TiO2),fluorine doping
更新于2025-09-10 09:29:36
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Carbon Nanotubes - Current Progress of their Polymer Composites || Carbon Nanotube-Conducting Polymer Composites as Electrode Material in Electroanalytical Applications
摘要： This chapter gives a brief overview of the preparation, characterization, and analytical applications for combinations of polymers and carbon nanotubes (CNTs) that have been prepared in different ways, which are used as an electrode material. For this purpose, multiwalled or single-walled CNTs are composed of different types of conductive polymers. The preparation of CNT-conducting polymer composite electrodes was explained by their deposition order. Chemical and morphological surface characteriza‐ tions of composite electrodes were presented by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. In addition, CNT-based polymer composite electrode usage in sensor applications for trace organic/inorganic compounds and energy applications is discussed in the last part of this chapter.
关键词： composite electrodes,conducting polymers,electron microscopy,Carbon nanotubes,metal nanoparticels scanning
更新于2025-09-10 09:29:36
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Application of spectroelectroanalysis for the quantitative determination of mixtures of compounds with highly overlapping signals
摘要： The amount of qualitative and quantitative information provided by a UV?vis absorption spectroelectrochemistry (SEC) experiment is sometimes wasted. However, almost all electrochemical and spectroscopic data can provide valuable information. In this spirit, the main objective proposed in this work is the quantitative resolution of catechol/dopamine (CAT/DA) and dopamine/epinephrine (DA/EP) mixtures, using spectroelectrochemical sensors in long optical path length arrangement based on bare optical fibers in parallel configuration with respect to carbon nanotubes or screen-printed electrodes. These compounds show extremely similar electrochemical and spectroscopic responses at high acidic pH, being impossible to determine their concentrations in the mixtures just using univariate regression models. To our knowledge, the SEC ability to resolve complex mixtures has never been demonstrated before with signals with this degree of overlapping. The quantitative analysis of these mixtures is possible using multivariate regression analysis of a set of time-resolved spectroelectrochemical data with a powerful statistical tool such as parallel factor analysis (PARAFAC). PARAFAC enables us to extract all the information from the experiments, allowing us to quantify the different analytes in mixtures of varying concentrations with excellent results. This milestone for spectroelectroanalysis illustrates the expected capabilities of SEC and demonstrates experimentally the potential of this technique for sensing of biomolecules.
关键词： screen-printed electrodes,dopamine,optical fibers,epinephrine,carbon nanotubes,spectroelectrochemistry
更新于2025-09-10 09:29:36
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Tailoring Physical Properties of Carbon Nanotube Threads During Assembly
摘要： Spinnable carbon nanotubes (CNTs) are useful formats for studying physical properties of CNT fiber assemblies in their pristine states. They are free of catalyst, uniform in length, with a comparatively narrow diameter distribution, and their assembly into thread does not require additional chemicals or solvents. Good quality drawable CNT arrays can be readily assembled into uniform diameter threads with great control over the number of CNTs incorporated into the thread assembly. This uniformity allows study the physical properties that result from changes that occur during thread formation. Here, we report trends of electrical resistivity and mechanical strength that resulted from alterations in their manufacturing parameters, allowing to change intrinsic physical properties of a material such as electrical resistivity. We correlate the electrical resistivity and mechanical strength as a function of diameter, density, and turns/meter. Understanding the effects of dry-spinning parameters will allow a better design of the physical properties of CNT threads for specific applications, such as strain or electrochemical sensors.
关键词： resistivity,threads,and twist angle.,fibers,yarns,Carbon nanotubes,diameter control
更新于2025-09-10 09:29:36