Key Laboratory of Advanced Functional Materials and Devices of Anhui Province

Hefei, China

Key Laboratory of Advanced Functional Materials and Devices of Anhui Province

Hefei, China
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Hong Y.,Hefei University of Technology | Hong Y.,Anhui Special Equipment Inspection Institute | Shi H.,Anhui Special Equipment Inspection Institute | Shu X.,Hefei University of Technology | And 5 more authors.
Particuology | Year: 2017

The controlled synthesis of hollow magnetite (Fe3O4) nanospheres of varying sizes and structures was successfully obtained via a facile solvothermal process and varying cooling processes. The Fe3O4 nanospheres were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and superconducting quantum interference device magnetometry. The diameters of the as-synthesized nanospheres were controlled at around 500-700nm by simply changing the cooling rate, which had an obvious influence on the morphology and magnetic properties of these Fe3O4 nanospheres. While a low cooling rate triggered the formation and extension of the cracks present in the Fe3O4 nanospheres, a sudden drop of temperature tended to favor multi-site nucleation of the crystals as well as the formation of compact and smooth hollow nanospheres with superior crystallinity and high saturation magnetization. The growth mechanism of hollow magnetite oxide nanospheres was proposed and the correlation between the structure and the magnetic properties of the hollow nanospheres was discussed, which promises the potential of the hollow nanospheres in various applications such as drug delivery and cell separation. © 2017 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.

Hui J.,Hefei University of Technology | Hui J.,Key Laboratory of Advanced Functional Materials and Devices of Anhui Province | Cui J.,Hefei University of Technology | Cui J.,Key Laboratory of Advanced Functional Materials and Devices of Anhui Province | And 5 more authors.
Materials Letters | Year: 2013

Direct electrochemistry of glucose oxidase (GOD) based on Nafion-Graphene-GOD modified gold disk electrode (GE) was studied in this work. Immobilized GOD on graphene protected by nafion film exhibited good bioactivity, stability and apparent electron transfer rate constant (ks) 1.96 s-1. Cyclic voltammetric results of the electrode showed a pair of well-defined and quasi-reversible redox peaks, suggesting the direct electron transfer between GOD and the electrode surface. The proposed biosensor exhibited a wider linear response to glucose concentrations between 2 and 14 mM with a detection limit of 0.04 mM and a higher sensitivity (21.9 μA mM-1 cm-2) compared with other nanostructured supports. © 2013 Elsevier B.V.

Lv J.,Hefei University of Technology | Wang H.,Hefei University of Technology | Gao H.,Hefei University of Technology | Xu G.,Hefei University of Technology | And 7 more authors.
Surface and Coatings Technology | Year: 2015

CdS and CdSe nanoparticles (NPs) were deposited on highly ordered TiO2 nanotube arrays (NTAs) by chemical bath deposition (CBD) and electrodeposition methods. FESEM, XRD, HRTEM, XPS, UV-Vis and EDX methods were employed to characterize the microstructure and composition of samples. CdSe and CdS nanoparticles were found to be uniformly deposited on the wall of TiO2 nanotubes after 10 controlled deposition cycles of CdS and a period of 600s deposition of CdSe. The photocatalytic performances of TiO2, CdS/TiO2, CdSe/TiO2 and CdSe/CdS/TiO2 NTAs were systematically investigated. Both single modification and co-modification extended the light absorption of TiO2 NTAs to the visible light range. The degradation rate of CdSe/CdS/TiO2 NTAs to Methyl Orange solution reached 96.0% after being irradiated in the visible light (250W metal halide lamp) for 2h, and remained at 84.3% after being reused for 15 times. Comparatively, the degradation rates of CdSe/TiO2 and CdS/TiO2 NTAs to Methyl Orange solution for the first use were just 92.8% and 89.8% respectively. Kinetic research shows that the apparent reaction rate constants for CdS/TiO2, CdSe/TiO2 and CdSe/CdS/TiO2 NTAs are 0.01889, 0.02176 and 0.02701min-1 respectively. © 2014 Elsevier B.V.

Chen Y.,Wuhan University | Yan Q.,Wuhan University | Zhang S.,Wuhan University | Lu L.,Wuhan University | And 8 more authors.
Journal of Power Sources | Year: 2016

In this work, designed growth of two type of N-doped graphene nanosheets has been investigated using NH4H2PO4 and (NH4)2HPO4 as buffering agents, respectively, in a mild hydrothermal process. X-ray photoelectron spectroscopy (XPS) characterization indicates that the graphene nanosheets grown using NH4H2PO4 (NGC) have lower nitrogen but higher oxygen content than those using (NH4)2HPO4 (NGL). Electrochemical measurements in three-electrode systems show that both type of the graphene products exhibit superior electrochemical performance (383 and 356 F g-1 at 1 A g-1). While the specific capacitance of NGC is steadily higher than that of NGL under all investigated current densities, the capacitance attenuation of NGL is 4.80% from 500 to 10000 cycles showing more durable in cyclicity than that of NGC (8.81%). The two-electrode supercapacitor devices for NGC and NGL exhibit high energy density of 12.21 Wh kg−1 and 9.28 Wh kg−1 at 0.25 A g−1. The difference in electrochemical behaviors between NGC and NGL electrodes can be attributed to the different contribution of nitrogen and oxygenic groups. The buffer agents assisted synthesis procedure coupled with the reasonable capacitance performance suggests an alternative way in the designed functionalization of graphene for developing high performance supercapacitors. © 2016 Elsevier B.V.

Xie B.,Wuhan University | Chen Y.,Wuhan University | Yu M.,Wuhan University | Sun T.,Wuhan University | And 6 more authors.
Carbon | Year: 2016

Graphene-based composites have been deemed as promising materials in renewable energy-storage applications. Herein, we report a hybrid architecture consisting of layered molybdenum sulfide nanosheets/N-doped graphene (MoS2/NG) synthesized by one-pot hydrothermal method. By adjusting precursor ratios, flower-like MoS2/NG hybrid with nitrogen content of 3.5 at.% on the graphene layers can be obtained. Electrochemical characterizations indicate that the maximum specific capacitance of the MoS2/NG electrodes reaches up to 245F/g at 0.25A/g (and 146F/g at 20A/g). In addition, the electrode exhibits superior cyclic stability with 91.3% capacitance retention after 1000 cycles at 2A/g. The outstanding performance of the MoS2/NG hybrid benefits from the synergistic effect between the layered MoS2 and N-doped graphene. © 2015 Elsevier Ltd. All rights reserved.

Xie B.,Wuhan University | Chen Y.,Wuhan University | Yu M.,Wuhan University | Zhang S.,Wuhan University | And 4 more authors.
RSC Advances | Year: 2016

A reformative graphene-supported MoS2 hybrid has been synthesized by a phosphoric acid (H3PO4)-assisted hydrothermal process. The effect of H3PO4 on the growth, morphology, structure, and composition of the MoS2/graphene hybrid has been explored by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results indicate that H3PO4 can control the process of both the reduction of graphene oxide and the crystallization of MoS2. The electrochemical performance suggests that involvement of H3PO4 in the reaction bestows the hybrid with electrolyte-dependent capacitive behaviors in which contribution from electric double-layer capacitance (EDLC) and pseudocapacitance can be distinguished in acidic and alkaline electrolytes, respectively. While the quasi-EDLC behavior of the hybrid dominates in an alkaline electrolyte (258 F g-1 at 2 A g-1), the pseudocapacitance of the hybrid in an acidic electrolyte can be significantly enhanced due to oxygen-containing groups and Mo active in the total capacitance value (351 F g-1 at 2 A g-1). Moreover, a superior cycling performance and quick frequency response of the hybrid reinforces its potential for supercapacitor applications. © 2016 The Royal Society of Chemistry.

Wang Z.,Hefei University of Technology | Wang Z.,CAS Hefei Institutes of Physical Science | Qin Q.,Hefei University of Technology | Xu W.,CAS Hefei Institutes of Physical Science | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2016

Long cyclic life is very important to the practical application of the pseudocapacitors. A systematic study has been carried out to reveal what key factors and how they affecting the cycling behaviors of manganese oxides. The specific capacitance degradation of MnOx is usually attributed to the so-called "dissolution" issue. Our results indicate that "dissoluted MnOx" is in the form of the "flotsam" derived from the detached active materials instead of Mn2+ in the solution, which causes color change of electrolyte and the loss of specific capacitance. During the cycling, the morphology of manganese oxides transformed to flower-like flakes regardless of the starting structures. After that, it tends to form nanowires especially at elevated temperatures. According to the relative low electrochemical utility of nanowires, specific capacitance might decrease at this stage. These results put forward new questions on charge storage mechanism. Besides, electrochemical oxidation of MnOx leads to an increase in specific capacitance. The cycling behavior of MnOx is mainly determined by these three factors. Excitingly, a very stable cycling performance with no capacitance degradation over 40000 cycles has been achieved in MnO2 hierarchical sphere-based electrodes. This study provides insightful understanding of the fundamental cycling behavior of MnOx-based electrodes and useful instructions for developing highly stable supercapacitors. © 2016 American Chemical Society.

Zhang X.,Hefei University of Technology | Cheng J.,Hefei University of Technology | Cheng J.,Key Laboratory of Advanced Functional Materials and Devices of Anhui Province | Li S.,Hefei University of Technology | Wang Y.,Hefei University of Technology
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2016

Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) powders were synthesized by a solid-state reaction method. The BSCF hollow fiber membranes with a diameter of 3 mm and a thickness of 400 μm were prepared by wet spinning and subsequently sintering processes. A BSCF porous layer was coated onto the outer surface of the BSCF hollow fiber membrane to modify the performance of oxygen permeation. The phase compositions of synthesized powders and hollow fiber membranes were analyzed by X-ray diffraction. The microstructure of the hollow fiber membrane was observed by scanning electron microscopy. The oxygen permeability of hollow fiber membranes were examined at different temperatures. The results indicate that the BSCF synthesized powders have a single perovskite phase. The BSCF hollow fiber membranes prepared by the wet spinning process have an asymmetric structure. The oxygen permeations of BSCF hollow fiber membrane in air/vacuum gradient are 0.382 and 1.284 mL/(cm2·min) at 700 and 900 ℃, respectively. After the surface modification, the oxygen permeation increases to 1.250 and 2.426 mL/(cm2·min), respectively. The activation energy of oxygen permeation decreases nearly a half after the surface modification, i.e., decreasing from 49.23 to 24.74 kJ/mol at 800-900 ℃. © 2016, Chinese Ceramic Society. All right reserved.

Wu G.J.,Hefei University of Technology | Xie K.,Hefei University of Technology | Xie K.,Key Laboratory of Advanced Functional Materials and Devices of Anhui Province | Wu Y.C.,Hefei University of Technology | Wu Y.C.,Key Laboratory of Advanced Functional Materials and Devices of Anhui Province
Advanced Materials Research | Year: 2014

This paper investigates a composite cathode La0.2Sr0.8TiO3+δ-Ce0.8Sm0.2O2-δ (LSTO-SDC) for the direct steam electrolysis in an oxide-ion-conducting solid oxide electrolyzer. The dependences of electrical conductivity of the reduced LSTO on temperature and oxygen partial pressure are studied and further correlated to the electrochemical properties of the cathode in symmetric cell LSTO-SDC/YSZ/LSTO-SDC and solid oxide electrolyzer LSTO-SDC/YSZ/LSM-SDC, respectively. Current efficiencies of the solid oxide electrolyzer with LSTO-SDC cathode were found to be 92.38% and 91.17% with or without reducing gas flowing over them under the applied voltage of 1.8 V at 800 °C, respectively. © (2014) Trans Tech Publications, Switzerland.

Dai J.-J.,Hefei University of Technology | Zhang W.-M.,Hefei University of Technology | Shu Y.-J.,Hefei University of Technology | Sun Y.-Y.,Hefei University of Technology | And 4 more authors.
Chemical Communications | Year: 2016

A photoredox catalytic method was developed for the direct cyanation of alkyltrifluoroborates. This reaction provides a new and useful transformation of the easily available alkyltrifluoroborates. The photocatalytic reaction can tolerate a variety of functional groups with mild reaction conditions. Mechanistic investigations are consistent with the present reaction following a radical pathway. © 2016 The Royal Society of Chemistry.

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