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Chen Y.,Nanchang Hangkong University | Huo M.,Nanchang Hangkong University | Chen T.,Nanchang Hangkong University | Chen T.,State Key Laboratory of Food Additive and Condiment Testing | And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2015

The structural stability and magnetic properties of iridium clusters Irn (n = 2-10) and their interaction on γ-Al2O3(001) and MgO(100) surfaces have been investigated from first principles calculations. It is found that the adsorption energy of Irn (n = 2-10)/γ-Al2O3(001) is lower than that of Irn/MgO(100); meanwhile, the strongest adsorption energy cluster for γ-Al2O3(001) is the tetrahedral Ir4 cluster, while for MgO(100) is a cubic Ir8 cluster. On the other hand, the nucleation of Irn (n = 2-10) clusters on both surfaces is thermodynamically favorable and exothermic. Moreover, the nucleation energy of Irn (n = 2-10) clusters on the γ-Al2O3(001) surface is close to the corresponding energy on the MgO(100) surface, except for Ir3, Ir4 and Ir6 clusters. Interestingly, the nucleation of Ir3 and Ir6 clusters on the MgO(100) surface is more favorable than that on the γ-Al2O3(001) surface, while the nucleation of the Ir4 cluster is reverse and very close to the gas phase Ir4 cluster. More importantly, deformation energy and charge density analysis show that the adsorbed Ir4 cluster on the γ-Al2O3(001) surface has obviously charge transfer between Ir atoms and surface Al, O atoms with negligible deformation. However, for the MgO(100) surface, the Ir4 cluster connects directly to three surface O atoms with severe distortion, which inhibits the activity of the tetrahedral Ir4 cluster as a catalyst. © the Owner Societies 2015.

Chen Y.-C.,Nanchang Hangkong University | Huo M.,Nanchang Hangkong University | Liu Y.,Sinopec | Chen T.,State Key Laboratory of Food Additive and Condiment Testing | And 4 more authors.
Chinese Physics Letters | Year: 2015

The layered Li2MnO3 is investigated by using the first-principles calculations within the GGA and GGA+U scheme, respectively. Within the GGA+U approach, the calculated intercalation voltage (ranges from 4.5V to 4.9 V) is found to be in good agreement with experiments. From the analysis of electronic structure, the pure phase Li2MnO3 is insulating, which is indicative of poor electronic-conduction properties. However, further studies of lithium ion diffusion in bulk Li2MnO3 show that unlike the two-dimensional diffusion pathways in rock salt structure layered cathode materials, lithium can diffuse in a three-dimensional pathway in Li2MnO3, with moderate lithium migration energy barrier ranges from 0.57 to 0.63 eV. © 2015 Chinese Physical Society and IOP Publishing Ltd.

Wang Y.,Jiangsu University | Li Y.,Jiangsu University | Han J.,Jiangsu University | Xia J.,Jiangsu University | And 3 more authors.
Fluid Phase Equilibria | Year: 2016

The cloud point (CP) values of aqueous solutions of the triblock copolymer L64 were determined in the absence and presence of five salting-out salts (K2SO4, Na2SO4, (NH4)2SO4, K2CO3, K2HPO4) at different concentrations. All the five salts could decrease the CP values and form aqueous two phase systems (ATPSs) with L64. A notable phase inversion phenomenon occurred with the increasing salt concentrations and the phase inversion points were found. The salt-rich phase transferred from the top phase to the bottom phase because of the change of density. Liquid-liquid equilibrium (LLE) data of these ATPSs were measured at 45 °C, respectively. The consistency of the tie-lines was verified by using the empirical equations from the Othmer-Tobias and Bancroft correlation. The effects on the cloudy behavior and phase separation depended on the salting-out ability. The results showed that the salting-out ability of the cations followed the order: Na+ > K+ > NH4 +; the anions followed the order: HPO4 2- > SO4 2- > CO3 2-. It could be concluded that using the Gibbs free energy of hydration of the ions (δGHyd) to estimate salting-out ability was not suitable for all of the ATPSs. © 2015 Elsevier B.V..

Rao W.,Jiangsu University | Wang Y.,Jiangsu University | Han J.,Jiangsu University | Wang L.,Jiangsu University | And 3 more authors.
Journal of Physical Chemistry B | Year: 2015

The cloud point of thermosensitive triblock polymer L61, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), was determined in the presence of various electrolytes (K2HPO4, (NH4)3C6H5O7, and K3C6H5O7). The cloud point of L61 was lowered by the addition of electrolytes, and the cloud point of L61 decreased linearly with increasing electrolyte concentration. The efficacy of electrolytes on reducing cloud point followed the order: K3C6H5O7 > (NH4)3C6H5O7 > K2HPO4. With the increase in salt concentration, aqueous two-phase systems exhibited a phase inversion. In addition, increasing the temperature reduced the concentration of salt needed that could promote phase inversion. The phase diagrams and liquid-liquid equilibrium data of the L61-K2HPO4/(NH4)3C6H5O7/K3C6H5O7 aqueous two-phase systems (before the phase inversion but also after phase inversion) were determined at T = (25, 30, and 35) °C. Phase diagrams of aqueous two-phase systems were fitted to a four-parameter empirical nonlinear expression. Moreover, the slopes of the tie-lines and the area of two-phase region in the diagram have a tendency to rise with increasing temperature. The capacity of different salts to induce aqueous two-phase system formation was the same order as the ability of salts to reduce the cloud point. © 2015 American Chemical Society.

Li K.,Nanchang Hangkong University | Zeng Z.,Nanchang Hangkong University | Xiong J.,Nanchang Hangkong University | Yan L.,Nanchang Hangkong University | And 4 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2015

Novel mesoporous CTAB-functionalized magnetic microspheres with a core/shell structure (mesoporous Fe3O4@SiO2@CTAB-SiO2) was fabricated via a simple sol-gel method combined with selective etching strategy. The morphology, porosity, magnetic property, composition, and structure of mesoporous Fe3O4@SiO2@CTAB-SiO2 were characterized. Subsequently, the as-prepared composites were successfully applied to remove trace PFOS (500ngL-1) from water at acidic conditions (pH=3). The fabrication mechanism of mesoporous Fe3O4@SiO2@CTAB-SiO2 and the impact of various factors on the removal of trace PFOS from water were systematically studied. The recyclability of the as-prepared composites was tested for, five times, at the same conditions. © 2014 Elsevier B.V.

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