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Chen H.,Jilin University | Ding Y.-H.,Jilin University | Yu H.-T.,Key Laboratory of Functional Inorganic Material Chemistry | Yu H.-T.,Heilongjiang University | Xie Y.,Heilongjiang University
Journal of Physical Chemistry C | Year: 2015

The first-principles thermodynamics characterization of the stabilities and electronic properties of the LaAlO3 (001) and (110) polar surfaces was systematically performed using density functional theory methods. Two types of polar surfaces, including the terminations along the (001) orientation (the LaO- and AlO2-terminated surfaces) and the (110) orientation (the LaAlO-, O2-, La-, AlO-, and O-terminated surfaces), were considered in this study. The computational results of the charge redistributions and geometries confirm that the electronic structure change and surface reconstruction should be responsible for the cancellation of the macroscopic dipole moments of these polar terminations, which stabilizes them. The charge neutralization can also be achieved by the charge redistribution of surface atoms. Furthermore, using the surface grand potential method in which the effect of the chemical environment on surface stability is considered, we constructed the stability phase diagram of the LaAlO3 (001) and (110) polar surfaces. The results indicate that only the O (110), LaO (001), and AlO2 (001) terminations have corresponding stability domains and can be considered targets in further experimental investigations. © 2015 American Chemical Society. Source


Ji Y.,Key Laboratory of Functional Inorganic Material Chemistry | Niu H.,Key Laboratory of Functional Inorganic Material Chemistry | Zhang H.,Key Laboratory of Functional Inorganic Material Chemistry | Wu W.,East China University of Science and Technology | And 4 more authors.
Journal of Solid State Electrochemistry | Year: 2014

The bismaleimide (BMI) monomer containing triphenylamine was prepared firstly. Then BMI was reacted with different diamines by Michael addition to obtain prepolymers, respectively. Finally, polyimides (PIs) were obtained through melting procedure. The effects of the structure of BMI moiety and thermal curing condition on thermal stability of PIs were studied by thermogravimetric analysis. PIs have excellent processing properties for film casting. Cyclic voltammetry of PI films was carried out on an indium-doped tin oxide-coated glass substrate. Results which exhibit two reversible oxidations at 0.71-0.78 and 1.06- 1.16 V vs Ag/AgCl. The electrochromic performance was investigated by spectroelectrochemical methods. These anodically coloring polymer films not only showed good electrochromic properties but also exhibited high optical contrast ratio of transmittance with a color changing from yellow to green. After 100 cyclic switches, the polymer films still retained excellent redox and electrochromic activity. © Springer-Verlag Berlin Heidelberg 2014. Source


Zhu Y.,Key Laboratory of Functional Inorganic Material Chemistry | Dong Y.,Key Laboratory of Functional Inorganic Material Chemistry | Dong Y.,Heilongjiang Institute of Science and Technology | Zhao L.,Key Laboratory of Functional Inorganic Material Chemistry | Yuan F.,Key Laboratory of Functional Inorganic Material Chemistry
Journal of Molecular Catalysis A: Chemical | Year: 2010

Vanadium oxide supported on mesoporous SBA-16 (VOx/SBA-16) catalysts have been prepared by the impregnation method and characterized by small-angle XRD, wide-angle XRD, TEM, N2-physisorption, DRUV-vis, Raman spectrum and H2-TPR. The VOx/SBA-16 catalysts retained the cubic cage-like pore structure of SBA-16. The dispersion and the nature of the vanadium species depend strongly on the V amount. At V loading of less than 3.6 wt%, isolated tetrahedral VO4 is the main existence species that is highly dispersed in the pores of the support SBA-16. With the increase in V loading, the aggregation of isolated tetrahedral VO4 species occurred to form polymerized VO4 units. When the V loading was above 5.5 wt%, nanostructured V2O5 crystallites were formed besides aggregation of polymerized VO4 units. VOx/SBA-16 with 7.3 wt% V showed excellent activity for the hydroxylation of benzene. The effect of reaction time, temperature and the amount of catalyst was investigated over VOx/SBA-16 (7.3 wt%) catalyst. The highest phenol yield and turnover number were 13.8% and 32.4, respectively, which were attributed to the formation of highly dispersed VO4 species and polymerized VO4 units. The TON and yield of phenol also increase in the presence of the V2O5 crystallites but its selectivity decreases. © 2009 Elsevier B.V. All rights reserved. Source


Li S.,Key Laboratory of Functional Inorganic Material Chemistry | Wang M.,Key Laboratory of Functional Inorganic Material Chemistry | Lian Y.,Key Laboratory of Functional Inorganic Material Chemistry
Science China Chemistry | Year: 2016

An improved Hummers method was developed for the simple and efficient production of high-quality graphene oxide (GO), and the composite of GO and nickel foam (NF) (GO/NF) was fabricated by ultrasonication-vacuum-assisted deposition of an aqueous solution of GO on NF. After chemical or thermal reduction, the composite of reduced GO and nickel foam (rGO/NF) was obtained. The electrochemical capacitance performance of rGO/NF was investigated using cyclic voltammetry and galvanostatic charge/discharge measurements. The chemically reduced rGO/NF composite (C-rGO/NF) exhibited high specific capacitance of 379 F/g at 1.0 A/g and 266.5 F/g at 10 A/g. We also prepared thermally reduced graphene oxide at 473 K in order to illuminate the difference in effect between the chemical and low-temperature thermal reduction methods on electrochemical properties. The cycling performance of thermally reduced rGO/NF composite (T-rGO/NF) and C-rGO/NF had ~91% and ~95% capacitance retention after 2000 cycles in a 6 mol/L KOH electrolyte, respectively. Electrochemical experiments indicated that the obtained rGO/NF has very good capacitive performance and could be used as a potential application of electrochemical capacitors. Our work revealed high electrochemical capacitor performance of rGO/NF composite and provided a facile method of rGO/NF preparation. © 2016 Science China Press and Springer-Verlag Berlin Heidelberg Source


Xia T.,Key Laboratory of Functional Inorganic Material Chemistry | Xia T.,Heilongjiang University | Bi H.,Key Laboratory of Functional Inorganic Material Chemistry | Bi H.,Heilongjiang University | And 2 more authors.
Journal of Chemical Sciences | Year: 2010

The NO electro-oxidation was investigated at various single-wall carbon nanotubes (SWCNTs) modified electrodes by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with the glassy carbon electrode, the SWCNTs modified electrodes possess higher electro-catalytic activity to NO electro-oxidation. CV results indicate that the peak current density of NO electro-oxidation at the SWCNT-COOH (SWCNTs with carboxyl groups) modified electrode is the highest and the peak potential is the most negative among the four kinds of electrodes. EIS indicates that the charge transfer resistance of NO electro-oxidation at the SWCNT-COOH modified electrode is the least. The determined factors (charge transfer and mass transfer of diffusion) of NO electro-oxidation are different in varied potential region. The mechanism of NO electro-oxidation reaction at the SWCNTs modified electrodes is also discussed. © Indian Academy of Sciences. Source

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