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排序方式: 共有300条查询结果,搜索用时 31 毫秒
91.
Wei Fen Jiang Yan Feng Zhang Yu Sheng Wang Lei Xu Xin Jian Li 《Applied Surface Science》2011,258(5):1662
A novel composite structure, Au nanoparticles coated on a nest-shaped array of carbon nanotube nested into a silicon nanoporous pillar array (Au/NACNT/Si-NPA), was fabricated for surface-enhanced Raman scattering (SERS). The morphology of the Au/NACNT/Si-NPA composite structure was characterized with the aid of scanning electron microscopy, X-ray diffraction instrumentation and Transmission electron microscopy. Compared with SERS of rhodamine 6G (R6G) adsorbed on SERS-active Au substrate reported, the SERS signals of R6G adsorbed on these gold nanoparticles were obviously improved. This was attributed to the enlarged specific surface area for adsorption of target molecules brought by the nest-shaped CNTs structure. 相似文献
92.
Neural electrodes are key tools for achieving a successful brain-computer interface and the electrodes should be small to minimize damage to neural tissue and obtain good spatial selectivity such as single unit recording. Here we show conventional platinum/tungsten neural probes can be coated with nanoporous Pt. Thanks to nanoporous Pt with the extremely small and uniform pores, L2-ePt, the electrode impedance could be reduced by more than 2 orders of magnitude while the apparent area was almost the same. L2-ePt coating enhanced neuronal recording of local field potential in monkeys, leading to facilitating implanted electrical devices in the nervous system. 相似文献
93.
Xiaoming Ma Dr. Yongli Shen Dr. Shuang Yao Miao Shu Prof. Rui Si Prof. Changhua An 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4143-4149
The key to the electrochemical conversion of CO2 lies in the development of efficient electrocatalysts with ease of operation, good conductivity, and rich active sites that fulfil the desired reaction direction and selectivity. Herein, an oxidative etching of Au20Cu80 alloy is used for the synthesis of a nanoporous Au3Cu alloy, representing a facile strategy for tuning the surface electronic properties and altering the adsorption behavior of the intermediates. HRTEM, XPS, and EXAFS results reveal that the curved surface of the synthesized nanoporous Au3Cu is rich in gold with unsaturated coordination conditions. It can be used directly as a self-supported electrode for CO2 reduction, and exhibits high Faradaic efficiency (FE) of 98.12 % toward CO at a potential of −0.7 V versus the reversible hydrogen electrode (RHE). The FE is 1.47 times that over the as-made single nanoporous Au. Density functional theory reveals that *CO has a relatively long distance on the surface of nanoporous Au3Cu, making desorption of CO easier and avoiding CO poisoning. The Hirshfeld charge distribution shows that the Au atoms have a negative charge and the Cu atoms exhibit a positive charge, which separately bond to the C atom and O atom in the *COOH intermediate through a bidentate mode. This affords the lowest *COOH adsorption free energy and low desorption energy for CO molecules. 相似文献
94.
Taher Alizadeh Fatema Rezaloo 《International journal of environmental analytical chemistry》2013,93(8):919-934
In this work, the application of molecularly imprinted polymer (MIP) as the recognition element of a chemiresistor sensor was introduced. Toluene-imprinted polymer and non-imprinted polymer (NIP) were synthesized and then mixed with carbon black powder in the presence of melted n-eicosane as the binder agent. The obtained composites were applied for the construction of chemiresistor sensors. The sensor, fabricated with toluene-imprinted polymer, showed a significant response towards toluene. Moreover, the response of the NIP-based (polymer synthesized without solvent) chemiresistor sensor was very small and negligible. The components of the MIP-based sensing composite were found to strongly influence the sensor sensitivity. Response surface experimental design methodology was applied to optimize the important parameters of the proposed sensor. Cross-sensitivity of the MIP-based chemiresistor sensor for different vapours was investigated and a satisfactory result was found for toluene vapour recognition. It was shown that the sensor response to toluene concentration in air was linear in the concentration range of 3.8 to 46.4?ppm. The detection limit and relative standard deviation (for five separate determinations) of the designed sensor were calculated equal to 0.8?ppm and 5.6%, respectively. 相似文献
95.
Sana Berijani Hassan Sereshti Parviz Norouzi 《International journal of environmental analytical chemistry》2013,93(3):355-365
In this research a new physically functionalized nanoporous silica (SBA-15) using N′-[(2-hydroxy phenyl) methylene] benzohydrazide (BBH) was utilized as a selective sorbent for the separation, preconcentration and determination of dysprosium (Dy) in natural water by inductively coupled plasma optical emission spectrometry (ICP-OES). The selectivity of BBH to Dy (III) ion was previously tested by conductometric and spectroscopic methods. Conditions for effective adsorption of Dy were optimized with respect to experimental parameters in batch process. The extraction recovery was 96.5, analytical curve was linear in the range 0.2–1000?µgL?1, and the detection limit was 0.05?ng?mL?1. The relative standard deviation (RSD) under optimal conditions was 3.2% (n?=?10). The sorbent exhibited high adsorption capacity and fast rate of equilibrium for sorption of Dy ions. The method was applied for recovery and determination of dysprosium in different environmental water samples. 相似文献
96.
Forouzan Aboufazeli Hamid Reza Lotfi Zadeh Zhad Omid Sadeghi Mohammad Karimi Ezzatolla Najafi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(1):18-24
In this work, MCM-41 (Mobil Composition of Matter number 41) nanoporous silica has been synthesized and characterized by X-ray powder diffraction and IR spectroscopy. In the next step, poly-thiophene was coated on the nanoporous silica in order to increase its surface area. This composite was characterized by X-Ray powder diffraction, High resolution transmission electronic microscopy micrograph (HRTEM), elemental analysis (CHNS) and Thermal analysis (TG/DTA). The application of this composite was investigated in mercury ions removal from waste water prior to determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In order to investigate the effect of nanoporous structure on the efficiency of this composite, the same composite without porous structure has been synthesized and the results were compared. 相似文献
97.
The present paper describes structural characteristics of crosslinked copolymers of acryl‐dicyclohexylurea (A‐DCU) and methacryl‐dicyclohexylurea (MA‐DCU) with ethylene glycole dimethacrylate (EDMA). Both copolymers decompose when heated at temperatures between 180–250°C under the separation cyclohexylisocyanate (C6H11NCO) yielding nanoporous copolymers of poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA). The comparison was also made between structural characteristics of crosslinked nanoporous copolymers of poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA) and nonporous crosslinked model compounds poly(A‐CHA‐co‐EDMA) and poly(MA‐CHA‐co‐EDMA). 相似文献
98.
Sher Alam Dr. Chokkalingam Anand Kripal Singh Lakhi Prof. Jin‐Ho Choy Wang Soo Cha Dr. Ahmed Elzhatry Prof. Salem S. Al‐deyab Prof. Yutaka Ohya Prof. Ajayan Vinu 《Chemphyschem》2014,15(16):3440-3443
The preparation of size‐controllable Fe2O3 nanoparticles grown in nanoporous carbon with tuneable pore diameters is reported. These hybrid materials exhibit strong non‐linear magnetic properties and a magnetic moment of approximately 229 emu g?1, which is the highest value ever reported for nanoporous hybrids, and can be attributed to the nanosieve effect and the strong interaction between the nanoparticles and the carbon walls. 相似文献
99.
Liu SJ Cheng HY Zhao FY Gong JY Yu SH 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(13):4074-4081
Nanoporous VSB-5 nickel phosphate molecular sieves with relatively well controllable sizes and morphology of microspheres assembled from nanorods were synthesized at 140 degrees C over a short time in the presence of hexamethylenetetramine (HMT) by a facile hydrothermal method. The pH value, reaction time, and ratio of HMT to NaHPO2.H2O crucially influence the morphology and quality of the final products. By adjusting the pH value of the initial reaction solution, the morphology changes from disperse rods to microspheres assembled from rods and finally to a large quantity of fibers, and the diameters of the VSB-5 rods can be varied. The catalytic activity of VSB-5 in selective hydrogenation of several unsaturated organic compounds was tested. Nickel(II) in VSB-5 can selectively catalyze hydrogenation of C=C in trans-cinnamaldehyde and 3-methylcrotonaldehyde. In addition, since nitrobenzene (NB) and 2-chloronitrobenzene could be reduced to aniline (AN) and 2-chloroaniline with high selectivity, VSB-5 could have potential applications in synthesizing dyes, agrochemicals, and pharmaceuticals. 相似文献
100.
A Titanium‐Doped SiOx Passivation Layer for Greatly Enhanced Performance of a Hematite‐Based Photoelectrochemical System 下载免费PDF全文
Dr. Hyo‐Jin Ahn Ki‐Yong Yoon Myung‐Jun Kwak Prof. Ji‐Hyun Jang 《Angewandte Chemie (International ed. in English)》2016,55(34):9922-9926
This study introduces an in situ fabrication of nanoporous hematite with a Ti‐doped SiOx passivation layer for a high‐performance water‐splitting system. The nanoporous hematite with a Ti‐doped SiOx layer (Ti‐(SiOx/np‐Fe2O3)) has a photocurrent density of 2.44 mA cm?2 at 1.23 VRHE and 3.70 mA cm?2 at 1.50 VRHE. When a cobalt phosphate co‐catalyst was applied to Ti‐(SiOx/np‐Fe2O3), the photocurrent density reached 3.19 mA cm?2 at 1.23 VRHE with stability, which shows great potential of the use of the Ti‐doped SiOx layer with a synergistic effect of decreased charge recombination, the increased number of active sites, and the reduced hole‐diffusion pathway from the hematite to the electrolyte. 相似文献