- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Direct transfer of the CVD-grown graphene on copper foils on SiO2 substrate under supercritical CO2 assisted-cleaning technique
摘要： The transfer of CVD-grown graphene sheets onto arbitrary substrates is important for the development of practical applications. Unfortunately, designing a low cost and highly efficient graphene transfer technique to achieve defect-free graphene sheets with low contact resistance onto various substrates still remains a challenge. In this paper, a CVD grown monolayer graphene sheet was directly transferred on SiO2/Si substrate. We found that a combination of floating copper with graphene films on ammonium persulfate solution with an original method of supercritical CO2 fluid can effectively produce clean and dry samples without damaging the crystalline quality of graphene. This method does not require any polymeric material to be desposited on the graphene films at any stage. Samples are analyzed by optical microscopy, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. This method is very promising for cleaning graphene samples for electronic device fabrication.
关键词： transfer technique,supercritical CO2,SiO2 substrate,graphene,CVD
更新于2025-09-23 15:19:57
-
Facile Synthesis of SiO <sub/>2</sub> –Ni Raspberry Composites by Electroless Plating and Polyelectrolyte Adsorption
摘要： Surface of mono-dispersed silica (SiO2) particles was modified by cationic polydiallyldimethylammonium chloride with an aim that negatively charged tetrachloropalladate (PdCl2?4) ions can be grafted electrostatically on the SiO2 surface in aqueous solutions. The PdCl2?4 ions changed into Pd(0) upon adsorption and acted as surface active sites for subsequent electroless nickel (Ni) deposition when sodium hypophosphite monohydrate was used as the reducing agent. By using nickel chloride as the metal precursor, SiO2–Ni raspberry-like nanocomposite particles were prepared. Morphology of the raspberry-like particles was examined when process variables such as reaction temperature, precursor concentration, and reducing agent concentration in the aqueous electroless plating were varied. Surface characteristics and microstructure of the SiO2–Ni particles were examined by electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry.
关键词： Composite,Electroless Plating,Ni,Polyelectrolyte,Pd,SiO2
更新于2025-09-19 17:15:36
-
SiO2-stabilized Bi nanoparticles: a high active and stable visible light photocatalyst
摘要： A SiO2-coated Bi nanoparticle structure in 40?60 nm with high activity and stability was designed by a liquid phase chemical reduction method. The effect of SiO2 layer on high active Bi nanoparticles was studied by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermo-gravimetric and differential thermal analysis characterizations. The SiO2 layer effectively enhanced the stability of Bi core without having negative effect on its activity. The as-prepared Bi@SiO2 nanoparticles showed high activity and recycling stability both in photocatalytic degradation of pollutant (rhodamine B and bisphenol A, respectively) and hydrogen exhalation reaction (HER). The photocatalytic degradation mechanism of Bi@SiO2 nanoparticles under visible light irradiation was discussed. The porous structure of SiO2 layer performed transport channel for electrons and active species, and enhanced the plasmonic photocatalytic effect of Bi.
关键词： HER.,stabilization,photocatalytic activity,Bi@SiO2 nanoparticles
更新于2025-09-19 17:15:36
-
The Use of TiO2-SiO2 in Photocatalytic Process to Degrade Toxic and Dangerous Waste
摘要： This study was conducted to investigate the use of TiO2 immobilized on SiO2 (TiO2-SiO2) in a photocatalytic process to degrade toxic industrial waste, phenol, linear alkylbenzene sulfonate (LAS), and Cr(VI), which is dangerous for humans and the environment. Titanium dioxide (TiO2), as a photocatalyst, can make the solution become turbid. Thus, TiO2-SiO2 was used to increase the possibility of ultraviolet (UV) transmission. The phenol and LAS levels were measured with the Indonesian National Standard (INS) while the Cr(VI) level was determined with the colorimetric method. The activity test for the catalyst in suspension and immobilization against phenol showed that TiO2-SiO2 was more active than TiO2. By using the photocatalytic process with the TiO2-SiO2 photocatalyst for 8 h, degradation of phenol and LAS reached 50% as a single compound and 12% as a mixture. However, TiO2-SiO2 did not decrease Cr(VI).
关键词： TiO2-SiO2,photocatalyst,LAS,Cr(VI),phenol
更新于2025-09-19 17:15:36
-
The preparation and luminescent characters of mesoporouss SiO2/Sm composite materials
摘要： During the mesoporous SiO2 preparation process, Sm3+ ions are dissolved in the anhydrous ethanol solution. The ethanol solution permeates the mesoporous SiO2 then the gel is formed by sol-gel synthesis method. Such, the Sm3+ ions are absolutely introduced into the porous of the mesoporous SiO2 when the gel is dried. In this study, the mesoporous SiO2/Sm3+ composite materials were synthesized by the sol-gel synthesis method. A series of characterization means were used to evaluate the structures of the materials. The near infrared spectrum was used to evaluate the luminescent characteristics. The excitation and emission spectrum of prepared materials showed that the materials had better near infrared luminescent characteristics.
关键词： character,luminescent,rare earth,SiO2 aerogel,sol-gel method
更新于2025-09-19 17:15:36
-
The Study on Titanium Dioxide-Silica Binary Mixture Coated SrAl2O4: Eu2+, Dy3+ Phosphor as a Photoluminescence Pigment in a Waterborne Paint
摘要： After proper stimulation, long afterglow phosphors formulated as pigment in waterborne paints can emit light after the removal of the excitation light source. The encapsulation of SrAl2O4: Eu2+, Dy3+ phosphor by TiO2 and SiO2 individually, and in combination by a precipitation method was studied. The water resistance and photoluminescence behavior of the coated phosphors as a pigment for potential use in waterborne photoluminescence paints were evaluated. It revealed that the TiO2- SiO2 content coating layer was precipitated on the studied phosphor successfully. The higher trend of the TiO2 for coating on the phosphor when compared with the SiO2 was observed from EDS spectra. The SEM micrographs showed a continuous and uniform SiO2-TiO2 layer on the coated phosphor. Based on XRD results, the existence of the TiO2 in the coating layer had beneficial effect on the average crystallite size values. The pH solution versus time showed that the availability of the TiO2 in coated layer improved water resistance of the coated phosphor, although, in comparison with SiO2, it was less effective. The coated phosphor with TiO2 had the minimum afterglow brightness decay and consequently, it was recommended as a suitable pigment for waterborne photoluminescence paints.
关键词： TiO2,SiO2,Pigment,Phosphor,Coating,Waterborne paint
更新于2025-09-19 17:15:36
-
Systematic Study of the SiOx Film with Different Stoichiometry by Plasma-Enhanced Atomic Layer Deposition and Its Application in SiOx/SiO2 Super-Lattice
摘要： Atomic scale control of the thickness of thin film makes atomic layer deposition highly advantageous in the preparation of high quality super-lattices. However, precisely controlling the film chemical stoichiometry is very challenging. In this study, we deposited SiOx film with different stoichiometry by plasma enhanced atomic layer deposition. After reviewing various deposition parameters like temperature, precursor pulse time, and gas flow, the silicon dioxides of stoichiometric (SiO2) and non-stoichiometric (SiO1.8 and SiO1.6) were successfully fabricated. X-ray photo-electron spectroscopy was first employed to analyze the element content and chemical bonding energy of these films. Then the morphology, structure, composition, and optical characteristics of SiOx film were systematically studied through atomic force microscope, transmission electron microscopy, X-ray reflection, and spectroscopic ellipsometry. The experimental results indicate that both the mass density and refractive index of SiO1.8 and SiO1.6 are less than SiO2 film. The energy band-gap is approved by spectroscopic ellipsometry data and X-ray photo-electron spectroscopy O 1s analysis. The results demonstrate that the energy band-gap decreases as the oxygen concentration decreases in SiOx film. After we obtained the Si-rich silicon oxide film deposition, the SiO1.6/SiO2 super-lattices was fabricated and its photoluminescence (PL) property was characterized by PL spectra. The weak PL intensity gives us greater awareness that more research is needed in order to decrease the x of SiOx film to a larger extent through further optimizing plasma-enhanced atomic layer deposition processes, and hence improve the photoluminescence properties of SiOx/SiO2 super-lattices.
关键词： plasma-enhanced atomic layer deposition (PEALD),stoichiometry,SiOx,SiO2,superlattice
更新于2025-09-19 17:15:36
-
A single light spot GC detector employing localized surface plasmon resonance of porous Au@SiO <sub/>2</sub> nanoparticle multilayer
摘要： This paper describes the synthesis of a nano-porous multilayered film consisting of Au@SiO2 nanoparticles. This film was used to miniaturize the size of a localized surface plasmon resonance (LSPR)-based capillary gas chromatograph (GC) detector. A layer-by-layer (LbL) approach with proper surface reaction sequences was used to create a multilayer structure that consisted of as many as five layers of Au@SiO2 nanoparticles. The center wavelength of LSPR was shifted from 520 to 634 nm due to the approximation of additional layers of nanoparticles. The vapor response time for this Au@SiO2 multilayer LSPR sensor was identical to that of an Au nanoparticle monolayer, which confirmed that this multilayer structure has a high level of gas permeability. The multilayer was synthesized inside a glass capillary for use as a GC detector. Due to the enhancement of absorbance, the gas chromatographic signal was obtained via a single spotlight that penetrated one side of the glass capillary and was then reflected by a silver mirror coated on the opposite side. The detection limits were ≤20 ng for cyclohexanone and m-xylene.
关键词： gas chromatography,localized surface plasmon resonance,multilayer film,miniaturization,Au@SiO2 nanoparticles,VOC detection
更新于2025-09-19 17:15:36
-
Efficient electrochemical detection and extraction of copper ions using ZnSe-CdSe/SiO2 core-shell nanomaterial
摘要： Development of nanostructured materials has received tremendous attention nowadays due to their unique properties and efficacious in wide range of applications. Herein, we present a facile synthesis of ZnSe-CdSe/SiO2 core-shell nanomaterial for pollutants monitoring and environmental remediation purposes. The utility of ZnSe-CdSe/SiO2 core-shell nanomaterial was explored toward electrochemical detection and adsorptive removal of copper ions from aquatic system. Experimental results reveal that both electrochemical detection and adsorption of Cu(II) using ZnSe-CdSe/SiO2 nanomaterial strongly depends on the solution pH, with an optimum pH of 5. Based on the results, the amperometric sensor based on ZnSe-CdSe/SiO2 core-shell nanomaterial modified electrode exhibited a detection limit of 50 μgL?1. Moreover, ZnSe-CdSe/SiO2 core-shell nanomaterial as adsorbent demonstrated high uptake capacity equals to 126.25 mgg?1. Thus, ZnSe-CdSe/SiO2 core-shell nanomaterial can be employed as promising material for several environmental remediation purposes.
关键词： Core-shell,Adsorption,Copper,ZnSe-CdSe/SiO2,Electrochemical Sensor,Nanomaterial,Extraction
更新于2025-09-19 17:15:36
-
Facile approach for the periodic poling of MgO-doped lithium niobate with liquid electrodes
摘要： The emerging quantum communication applications advance the rapid development of up-conversion single-photon detectors and entangled photon-pair sources, of which the core components are both based on frequency conversion in periodically poled lithium niobate (PPLN) waveguides. The MgO-doped congruent lithium niobate (Mg:LN) is known as the most promising material for the fabrication of PPLN because of its attractive properties, but the leakage current complicates the high-quality periodic poling of Mg:LN, especially for the technique with liquid electrodes. In this paper, we demonstrated an effective approach to suppress the leakage current by using SiO2 dielectric layer of appropriate thickness, and high-quality periodic poling has been realized in 5 mol.% Mg:LN wafers with the diameter of 76.2 mm based on the electric-field poling method using liquid electrodes. The ease of clear remove of the liquid electrodes benefits for the fabrication of waveguides on the wafer surface, and the wafer-level manufacture of PPMgLN with easy operation and high rate of finished products facilitates the mass production of PPMgLN devices for quantum communication applications.
关键词： liquid electrodes,leakage current,Mg:LN,periodic poling,SiO2 dielectric layer
更新于2025-09-19 17:15:36