- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Facile synthesis of ZnBi2O4-graphite composites as highly active visible-light photocatalyst for the mineralization of rhodamine B
摘要： Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide (ZnBi2O4) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at 450 oC. The as-prepared ZnBi2O4-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the ZnBi2O4-graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of 50 mg·L?1 with 1.0 g catalyst per liter in 150 min. The excellent visible-light photocatalytic mineralization of ZnBi2O4-1.0graphite in comparison with pristine ZnBi2O4 could be attributed to synergetic effects, charge transfer between ZnBi2O4 and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced h+ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of ZnBi2O4-1.0graphite as a potential heterogeneous photocatalyst for environmental remediation.
关键词： ZnBi2O4,Mineralization,Degradation,Graphite,Photocatalyst
更新于2025-09-09 09:28:46
-
Effect of Defects on Diffusion Behaviors of Lithium-ion Battery Electrodes: In Situ Optical Observation and Simulation
摘要： Lithium-ion batteries (LIBs) with high energy efficiency are urgeniltly needed in various fields. For the LIBs electrodes, defects would be generated during manufacture processes and mechanical degradation, and the defects significantly impact the stability and performance of LIBs. However, the effects of electrode defects on the electrochemical processes are still not clear. Herein, an in situ optical observation system is developed for monitoring the Li diffusion around the pre-introduced defects in the commercial graphite electrodes. The experiments show the gas-filled defects vertical to the direction of the Li diffusion would obviously decelerate Li diffusion, while the electrolyte-filled defects parallel to the direction of the Li diffusion would accelerate Li diffusion. In addition, finite element analysis (FEA) suggests consistent with the experiments, showing nonuniform distribution of local Li concentration around the defect. The equivalent diffusivity obtained by FEA is also dependent on the configuration of the defects. The diffusivities of electrolyte-filled parallel defect and gas-filled vertical defect are 12.6 % and 11.0 %, respectively. For the gas-filled defects, the size-effect calculation manifests that equivalent diffusivity would decrease with the enlarged defect size, and the shape of the defects would substantially impact the decrease rate. The results directly reveal the mechanisms of defect induced diffusion behavior change in the electrodes by the new equivalent 2D experiments, and the equivalent diffusivity would be useful for optimizing electrode designs in LIBs.
关键词： colorimetric method,defect,graphite anode,lithium-ion battery,diffusion
更新于2025-09-09 09:28:46
-
VO<sub>2</sub>-Enhanced double positive temperature coefficient effects of high density Polyethylene/Graphite composites
摘要： High density polyethylene/graphite (HDPE/Gr) composites were fabricated by the melt-blending method, and displayed the enhanced positive temperature coefficient (PTC) effect and decreasing room-temperature resistivity with the addition of vanadium dioxide (VO2). Especially, HDPE/Gr composite with 6 wt% VO2 showed the remarkable double PTC effects and excellent reproducibility. Based on obvious two-shape structure and heating amorphous evolution of HDPE composites, the simple filler-compensated conductive networks and unique dispersion model were constructed to further understand the PTC behavior. Finally, it was concluded that the excellent double PTC effects of single polymer composites were achieved by the introduction of second filler.
关键词： PTC effect,Graphite,Vanadium Dioxide,High Density Polyethylene
更新于2025-09-09 09:28:46
-
[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - The use of Films of Metal-Containing Nanocomposites with a Silicon-Carbon Matrix in Thermal Imitators of the Components of Micro-and Nanoelectronics
摘要： The installation scheme and features of the technology for obtaining alloyed diamond-like silicon-carbon films are presented and the heating elements based on these films are created to be used as thermal imitators of micro- and nanoelectronical products and their modules with increased specific heat flux (such as microprocessors, high-frequency microcircuits of the transmit-receive modules, LEDs, lasers, etc.). The matrix of the alloyed diamond-like silicon-carbon film has an amorphous nanocomposite structure, into which the inclusions having nanodimensions and composed of chromium and its compounds with carbon are introduced. Due to the controlled change in the parameters of the process of film deposition, it is possible to obtain a given specific resistance of a doped diamond-like silicon-carbon film over a wide range: from 10-4 to 1014 (cid:525)·cm. The electrical resistance of the manufactured heating elements with dimensions of 7x30x1 mm on the basis of a diamond-like silicon-carbon film 1 (cid:541)m thick, doped with chromium, was 15 (cid:525). Using four such heating elements with a total resistance of 60 ohms made it possible to create a compact detachable thermal imitator of the electronic module with a maximum power of 806 W. Application of the developed thermal imitator accelerates the process of research and improvement of heat sink devices for products of micro- and nanoelectronics.
关键词： heating element,thermal imitator,micro- and nanoelectronical products,alloyed diamond-like carbon-graphite nanocomposite structure
更新于2025-09-09 09:28:46
-
Visible-light-responsive bismuth oxybromide/graphite-like C3N4 hybrid material and its application in photocatalysis via internal electric field
摘要： In this work, we propose a facile route to obtain BiOBr/ graphite-like C3N4 hybrid material, which was constructed by in situ depositing BiOBr onto the surface of g-C3N4 as a template via self-assembly procedure at room temperature. This method describes the use of g-C3N4/BiOBr nanocomposite for the superior photocatalytic performances under visible light excitation (λ > 420 nm). The crystalline phase, morphology, textile structure and components of the samples were studied by several tools such as X-ray diffraction, transmission electron microscopy, N2 adsorption–desorption, energy dispersive X-ray spectrum, Fourier transform infrared spectroscopy and Raman spectroscopy. The optical, photoelectrochemical properties and band structure were measured by ultraviolet–visible diffuse reflectance spectroscopy, steady-state photoluminescence spectra, photocurrent response analysis, electrochemical impedance spectra and valence-band X-ray photoelectron spectroscopy techniques, respectively. In addition, the catalytic activities of the hetero-structural material were broadly investigated and compared with single BiOBr or g-C3N4 alone in the same reaction. The as-obtained BiOBr/g-C3N4 composite showed distinctive advantages over BiOBr alone and universality for various substrate, i.e., dichloronaphthol degradation and reduction efficiency of Cr (VI) over BiOBr/g-C3N4 was increased by up to 3 and 2.5 times, respectively. The enhanced photocatalytic activity of the as-prepared BiOBr/g-C3N4 complex was mainly contributed to the effective charge transfer, which can further cause the establishment of the internal electric field in the interface between BiOBr and g-C3N4 to boost the space charge separation. This work gives a new route for designing high efficient semiconductor hybrid photocatalyst with broad absorption region as well as quick charge separation.
关键词： Graphite-like C3N4,BiOBr,Self-assembly,Photoelectrochemical,Internal electric field
更新于2025-09-04 15:30:14
-
Two-ply anode X-ray tube for computed tomography scanner
摘要： This report presents a method of the formation of tungsten layer on the graphite surface. The described method can be used to create the anode of powerful x-ray tubes for medical purposes, in particular, a computer tomograph (CT). The thermal properties of the graphite base and the deposited tungsten coating, as well as the strength of the resulting coating were studied. Thermal fields in the CT-anode with a power of 100 kW were calculated.
关键词： tungsten layer,thermal properties,tungsten coating,thermal fields,graphite surface,computer tomograph,x-ray tubes
更新于2025-09-04 15:30:14
-
Ohmic graphite-metal contacts on oxygen-terminated lightly boron-doped CVD monocrystalline diamond
摘要： A process to obtain ohmic contacts on oxygen-terminated lightly boron-doped CVD monocrystalline diamond films was developed. Samples were contacted by Ti/Au metallic pads in the transmission line model (TLM) configuration. The electric contacts were placed onto a mesa structure produced on the CVD boron-doped layer. One of the samples was additionally implanted with helium ions at 10 keV in order to induce the formation of a graphitic layer underneath the diamond surface before contacting so as to improve electrical conduction. The electrical performance of both devices was characterized by the TLM method and compared. As a result, the sample with metallic electrodes exhibited a small and non-linear electrical conduction, while the graphitic/metallic contacts showed an ohmic behaviour with an estimated specific contact resistance as low as 3.3 × 10-4 Ω.cm2 for a doping level of a few 1017 cm-3. This approach opens the way to more efficient ohmic contacts on intrinsic or low-doped diamond that are crucial for the development of electronic devices and detectors.
关键词： oxygen terminations,graphitization,Ohmic graphite-metal contacts,lightly boron-doped CVD diamond film,ion implantation
更新于2025-09-04 15:30:14