In the last 30 days

• Open/close Synthesis of Various Metal/TiO₂ Core/shell Nanorod Arrays

  Wei Zhu et al 2011 Chin. J. Chem. Phys. 24 91 Tag this article

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  We present a general approach to fabricate metal/TiO ₂ core/shell nanorod structures by two-step electrodeposition. Firstly, TiO ₂ nanotubes with uniform wall thickness are prepared in anodic aluminum oxide (AAO) membranes by electrodeposition. The wall thickness of the nanotubes could be easily controlled by modulating the deposition time, and their outer diameter and length are only limited by the channel diameter and the thickness of the AAO membranes, respectively. The nanotubes' tops prepared by this method are open, while the bottoms are connected directly with the Au film at the back of the AAO membranes. Secondly, Pd, Cu, and Fe elements are filled into the TiO ₂ nanotubes to form core/shell structures. The core/shell nanorods prepared by this two-step process are high density and free-standing, and their length is dependent on the deposition time.

• Open/close Shape-Controlled Synthesis of Palladium Nanoparticles and Their SPR/SERS Properties

  Xiao-shuang Shen et al 2009 Chin. J. Chem. Phys. 22 440 Tag this article

  Article References Full text PDF (6.76 MB)

  Morphological evolution of Pd nanoparticles was studied in a solution-phase synthesis using cetyltrimethylammonium bromide (CTAB) and CTAB/sodium citrate mixture as capping agents, respectively. The morphological diversity of Pd nanoparticles is the combined effect of different Pd twinned seeds formed in the nucleation stage and selectively enlarging one set of crystallographic facets in the growth stage, both of which can be affected by the concentrations of CTAB. Through changing the concentrations of CTAB and sodium ascorbate, Pd nanoparticles with different shapes were obtained. When citrate ions were introduced to manipulate the nucleation and growth process, star-shaped icosahedra and nanorods with pentagram cross-sections were obtained. Pd nanoparticles with different shapes have quite different surface plasmon resonance and surface-enhanced Raman scattering properties.

• Open/close Preparation and Characterization of Electrodeposited-Annealed CuInSe₂ Thin Films for Solar Cells

  Zhong-wei Zhang et al 2011 Chin. J. Chem. Phys. 24 225 Tag this article

  Article References Full text PDF (1.51 MB)

  CuInSe ₂ (CIS) films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 °C. The morphology, composition, crystal structure, optical and electrical properties of the CIS films were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-VIS-NIR spectroscopy, and admittance spectroscopy. The results revealed that the annealed CIS films had chalcopyrite structure and consisted of relatively large grains in the range of 500–1000 nm and single grain of films extend usually through the whole film thickness. The band gap of CIS films was 0.98 eV and carrier concentration was in the order of 10 ¹⁶ cm ⁻³ after etching the Cu-Se compounds on the film surface. Solar cells with the structure of AZO/i-ZnO/CdS/CIS/Mo/glass were fabricated. Current density vs. voltage test under standard reported condition showed the solar cells with an area of 0.2 cm ² had a conversion efficiency of 0.96%. The underlying physics was also discussed.

• Open/close Synthesis of Multishell Carbon Nanotube Composites via Template Method

  Wen-bo Li et al 2011 Chin. J. Chem. Phys. 24 206 Tag this article

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  Multishell nanotubes of polyaniline and carbon were synthesized via a template approach. A thin layer of MnO ₂ coated on carbon nanotubes acts as a reactive template for the consequent formation of the polyaniline coating. The polyaniline-carbon nanotubes show enhanced dispersibility in water and can be possibly used as a functional material of electrochemical capacitors with improved performance. The general method operates by coating carbon nanotubes on functional materials such as poly (3,4-ethylenedioxythiophene), polypyrrole, silica, and carbon.

• Open/close Oxidative Coupling of Methane over Li/MgO: Catalyst and Nanocatalyst Performance

  Ali Farsi et al 2011 Chin. J. Chem. Phys. 24 70 Tag this article

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  The Li/MgO catalyst and nanocatalyst were prepared by the incipient wetness impregnation and sol-gel method, respectively. The catalytic performance of the Li/MgO catalyst and nanocatalyst on oxidative coupling of methane was compared. The catalysts prepared in two ways were characterized by X-ray powder diffraction, Brunauer-Emmett-Teller surface and transmission electron microscope. The catalyst was tested at temperature of 973–1073 K with constant total pressure of 101 kPa. Experimental results showed that Li/MgO nanocatalyst in the oxidative coupling of methane would result in higher conversion of methane, higher selectivity, and higher yield of main products (ethane and ethylene) compared to ordinary catalyst. The results show the improved influence of nanoscale Li/MgO catalyst performance on oxidative coupling of methane.

• Open/close Synthesis and Adsorption Study of BSA Surface Imprinted Polymer on CdS Quantum Dots

  Ping-ping Tang et al 2010 Chin. J. Chem. Phys. 23 195 Tag this article

  Article References Full text PDF (1.33 MB)

  A new bovine serum albumin (BSA) surface imprinting method was developed by the incorporation of quantum dots (QDs) into molecularly imprinted polymers (MIP), which can offer shape selectivity. Preparation and adsorption conditions were optimized. Physical appearance of the QDs and QDs-MIP particles was illustrated by scanning electron microscope images. Photoluminescence emission of CdS was quenched when rebinding of the template. The quenching of photoluminescence emissions is presumably due to the fluorescence resonance energy transfer between quantum dots and BSA template molecules. The adsorption is compiled with Langmuir isotherm, and chemical adsorption is the rate-controlling step. The maximum adsorption capacity could reach 226.0 mg/g, which is 142.4 mg/g larger than that of undoped BSA MIP. This study demonstrates the validity of QDs coupled with MIP technology for analyzing BSA.

• Open/close Urchin-like Co₃O₄ Nanostructure and Their Electrochemical Behavior in Rechargeable Lithium Ion Battery

  Hui Li et al 2011 Chin. J. Chem. Phys. 24 343 Tag this article

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  3D urchin-like Co ₃O ₄ have been successfully prepared by calcination of the urchin-like precursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co ₃O ₄ have been characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray powder diffraction. The as-synthesized Co ₃O ₄ products are of urchin-like structures with approximated 5–7 μm in diameter, and are composed of numerous nanoparticles chains with the particles diameter of about 15 nm. This kind of urchin-like Co ₃O ₄ exhibits superior energy storage properties with the high capacity of 1.369 Ah/g and its good cyclic stability shows great potential in the rechargeable Li-ion battery.

• Open/close Molecular Dynamics Simulation on Stability of Insulin on Graphene

  Li-jun Liang et al 2009 Chin. J. Chem. Phys. 22 627 Tag this article

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  The adsorption dynamics of a model protein (the human insulin) onto graphene surfaces with different sizes was investigated by molecular dynamics simulations. During the adsorption, it has different effect on the stability of the model protein in the fixed and non-fixed graphene systems. The tertiary structure of the protein was destroyed or partially destroyed, and graphene surfaces shows the selective protection for some α-helices in non-fixed systems but not in fixed systems by reason of the flexibility of graphene. As indicated by the interaction energy curve and trajectory animation, the conformation and orientation selection of the protein were induced by the properties and the texture of graphene surfaces. The knowledge of protein adsorption on graphene surfaces would be helpful to better understand stability of protein on graphene surfaces and facilitate potential applications of graphene in biotechnology.

• Open/close Nearly Free Electron State in Graphane Nanoribbon Superlattice

  Qiao-hong Liu et al 2011 Chin. J. Chem. Phys. 24 22 Tag this article

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  Nearly free electron (NFE) state has been widely studied in low dimensional systems. Based on first-principles calculations, we identify two types of NFE states in graphane nanoribbon superlattice, similar to those of graphene nanoribbons and boron nitride nanoribbons. Effect of electron doping on the NFE states in graphane nanoribbon superlattice has been studied, and it is possible to open a vacuum transport channel via electron doping.

• Open/close Pulsed Laser Deposition ZnS Buffer Layers for CIGS Solar Cells

  Pai-feng Luo et al 2009 Chin. J. Chem. Phys. 22 97 Tag this article

  Article References Full text PDF (3.13 MB)

  Polycrystalline ZnS films were prepared by pulsed laser deposition (PLD) on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 °C, which is a suitable alternative to chemical bath deposited (CBD) CdS as a buffer layer in Cu(In,Ga)Se ₂ (CIGS) solar cells. X-ray diffraction studies indicate the films are polycrystalline with zinc-blende structure and they exhibit preferential orientation along the cubic phase β-ZnS (111) direction, which conflicts with the conclusion of wurtzite structure by Murali that the ZnS films deposited by pulse plating technique was polycrystalline with wurtzite structure. The Raman spectra of grown films show A ₁ mode at approximately 350 cm ⁻¹, generally observed in the cubic phase β-ZnS compounds. The planar and the cross-sectional morphology were observed by scanning electron microscopic. The dense, smooth, uniform grains are formed on the quartz glass substrates through PLD technique. The grain size of ZnS deposited by PLD is much smaller than that of CdS by conventional CBD method, which is analyzed as the main reason of detrimental cell performance. The composition of the ZnS films was also measured by X-ray fluorescence. The typical ZnS films obtained in this work are near stoichiometric and only a small amount of S-rich. The energy band gaps at different temperatures were obtained by absorption spectroscopy measurement, which increases from 3.2 eV to 3.7 eV with the increasing of the deposition temperature. ZnS has a wider energy band gap than CdS (2.4 eV), which can enhance the blue response of the photovoltaic cells. These results show the high-quality of these substitute buffer layer materials are prepared through an all-dry technology, which can be used in the manufacture of CIGS thin film solar cells.