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Liang P.,Key Laboratory for Nanomaterials | Zhang Y.,Tianjin Polytechnic University | Huang S.,Key Laboratory for Nanomaterials | Wang P.,Sinopec | Tian H.,Sinopec
Journal of Computational and Theoretical Nanoscience | Year: 2011

The nanoparticles of cubic ZrO 2 containing 324, 768, and 1500 atoms from 1 GPa to 20 GPa are investigated by using molecular dynamics simulations. The hydrostatic pressure is employed in the system, while an ideal gas is used as the pressure medium and thermostat in the molecular dynamics simulations. Using this method, we study the pressure-induced structural transformation from the four-coordinated to six- or eight-coordinated Zr-O arrangements during the pressurized process. The total correlation function T(r), coordination number and bond-angle distribution are all calculated in order to analyze the structural properties of ZrO 2 nanoparticles. The ZrO 2 nanoparticles containing 324 and 768 atoms have only one structural transition, which take place under 9~10 GPa and 8~11 GPa. The large nanoparticle with 1500 atoms undergoes two structural transitions. The first structural transformation occurs at 7~8 GPa and the other is at 14~16 GPa with the increase in pressure. Copyright © 2011 American Scientific Publishers.

An W.-W.,Key Laboratory for Nanomaterials | Le Y.,Key Laboratory for Nanomaterials | Chen J.-F.,Beijing University of Chemical Technology
INEC 2010 - 2010 3rd International Nanoelectronics Conference, Proceedings | Year: 2010

Toluidine red (TR) pigment nanoparticles were prepared by anti-solvent precipitation and were modified by different surfactants aimed to use as the electrophoretic particles. Binary mixtures of organic solvents were selected as suspending medium to improve the dispersion stability of the prepared particles. The results indicated that the recrystallized particles modified by alkyl hydroxy oximido acid (AHOA) showed in round shape with the average size of 80nm. The prepared nanoparticles exhibited superior electrophoretic properties. Finally, the sedimentation for 2 months was 4.76% for charged particles dispersed into binary mixtures of tetrachloroethylene and cyclohexane. ©2010 IEEE.

Xiang Z.,Key Laboratory for Nanomaterials | Cao D.,Key Laboratory for Nanomaterials | Shao X.,Key Laboratory for Nanomaterials | Wang W.,Key Laboratory for Nanomaterials | And 2 more authors.
Chemical Engineering Science | Year: 2010

The Cu3(BTC)2 Metal-oragnic frameworks (MOFs) are synthesized by four different processes, i.e. solvothermal method (sample 1), microwave-assisted solvothermal method (sample 2), a combination of solvothermal method and supercritical carbon dioxide (Sc-CO2) activation (sample 3) and a combination of microwave-assisted solvothermal method and Sc-CO2 activation (sample 4). By comparing the N2 adsorption isotherms of the four samples, it is found that the sample 4 displays the greatest N2 uptake. Due to the best performance of sample 4 in N2 adsorption, we further study H2 adsorption in the sample 4. Results indicate that the excess and absolute hydrogen uptakes of this material reach 4.12 and 4.49 wt% at T=77 K and P=18 bar, respectively, which is the largest one among all these reports on Cu3(BTC)2 for H2 storage at the same condition. Therefore, it is believed that a combination of the two technologies of microwave-assisted method and supercritical Sc-CO2 activation provides a new approach for chemical engineers rapidly and efficiently preparing MOFs for high-capacity H2 storage. © 2010 Elsevier Ltd. All rights reserved.

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