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Dong Xiang

Bio: Dong Xiang is an academic researcher from Shandong University. The author has contributed to research in topics: Mesoporous material & Quantum dot. The author has an hindex of 6, co-authored 6 publications receiving 2380 citations. Previous affiliations of Dong Xiang include Shandong jianzhu university 山東建築大學.

Papers
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Journal ArticleDOI
Cheng-Xiang Wang1, Longwei Yin, Luyuan Zhang, Dong Xiang, Rui Gao 
15 Mar 2010-Sensors
TL;DR: A brief review of changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors: chemical components, surface-modification and microstructures of sensing layers, temperature and humidity.
Abstract: Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above.

2,122 citations

Journal ArticleDOI
Luyuan Zhang1, Longwei Yin1, Cheng-Xiang Wang1, Ning Lun1, Yong-Xin Qi1, Dong Xiang1 
TL;DR: ZnO quantum dots with tunable diameters in a range of 22−78 nm were synthesized via a sol−gel route using self-made zinc−oleate complex as a precursor.
Abstract: To get a real understanding on the complexity of origin and mechanism of visible emission for ZnO quantum dots (QDs), we systematically property of visible emission of ZnO QDs with tunable diameters in a range of 22−78 nm synthesized via a sol−gel route using self-made zinc−oleate complex as a precursor It is indicated that the visible emission of ZnO QDs can be ascribed to singly ionized oxygen vacancies, which is associated with the paramagnetic centers with electron paramagnetic resonance (EPR) value of g = 20056 The visible emission property of the ZnO QDs displays highly size-dependent behavior With ZnO QDs size decreasing, the visible emission peaks blue-shift to the positions with shorter wavelength due to quantum size effect, however, is different from that of band gap Quantitative investigation shows that the visible emission can correspond to a transition of holes from the valence band to the preexisting deep donor energy level, which is different from the well-known conclusion that the v

317 citations

Journal ArticleDOI
TL;DR: Because of the low-cost, nonpollution, and stable capacity, the carbon homogeneously coated Mn(3)O(4)@C nanocomposites are promising anode material for lithium ion batteries.
Abstract: A facile one-step solvothermal reaction route to large-scale synthesis of carbon homogeneously wrapped manganese oxide (Mn3O4@C) nanocomposites for anode materials of lithium ion batteries was developed using manganese acetate monohydrate and polyvinylpyrrolidone as precursors and reactants. The synthesized Mn3O4@C nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The synthesized tetragonal structured Mn3O4 (space group I41/amd) samples display nanorodlike morphology, with a width of about 200–300 nm and a thickness of about 15–20 nm. It is shown that the carbon layers with a thickness of 5 nm are homogeneously coated on the Mn3O4 nanorods. It is indicated from lithium storage capacity estimation that the Mn3O4@C samples display enhanced capacity retention on charge/discharge cycling. Even after 50 cycles, the products remains stable capacity of 473...

222 citations

Journal ArticleDOI
01 Oct 2010-Carbon
TL;DR: In this article, the effect of synthesis temperatures and pre-existing precursors on the pore diameter and C/N molar ratio of mesoporous nitrogen-doped carbon (N-MC) was investigated.

99 citations

Journal ArticleDOI
01 Jul 2016-Energy
TL;DR: In this article, the mesoporous structure optimized the electron and proton conducting pathways, leading to the enhanced capacitive performances of the composite materials RuO2 or RuO 2 -Fe 2 O 3 /OMC.

66 citations


Cited by
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01 Nov 2000
TL;DR: In this paper, the authors compared the power density characteristics of ultracapacitors and batteries with respect to the same charge/discharge efficiency, and showed that the battery can achieve energy densities of 10 Wh/kg or higher with a power density of 1.2 kW/kg.
Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

2,437 citations

Posted Content
TL;DR: The two-step solution-phase reactions to form hybrid materials of Mn(3)O(4) nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications should offer a new technique for the design and synthesis of battery electrodes based on highly insulating materials.
Abstract: We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

1,587 citations

Journal ArticleDOI
TL;DR: In this paper, the dominant electronic and chemical mechanisms that influence the performance of metal-oxide-based resistive-type gas sensors are discussed, including p-n and n-n potential barrier manipulation, n-p-n response type inversions, spillover effects, synergistic catalytic behavior, and microstructure enhancement.
Abstract: Metal oxide-based resistive-type gas sensors are solid-state devices which are widely used in a number of applications from health and safety to energy efficiency and emission control. Nanomaterials such as nanowires, nanorods, and nanoparticles have dominated the research focus in this field due to their large number of surface sites facilitating surface reactions. Previous studies have shown that incorporating two or more metal oxides to form a heterojunction interface can have drastic effects on gas sensor performance, especially the selectivity. Recently, these effects have been amplified by designing heterojunctions on the nano-scale. These designs have evolved from mixed commercial powders and bi-layer films to finely-tuned core–shell and hierarchical brush-like nanocomposites. This review details the various morphological classes currently available for nanostructured metal-oxide based heterojunctions and then presents the dominant electronic and chemical mechanisms that influence the performance of these materials as resistive-type gas sensors. Mechanisms explored include p–n and n–n potential barrier manipulation, n–p–n response type inversions, spill-over effects, synergistic catalytic behavior, and microstructure enhancement. Tables are presented summarizing these works specifically for SnO2, ZnO, TiO2, In2O3, Fe2O3, MoO3, Co3O4, and CdO-based nanocomposites. Recent developments are highlighted and likely future trends are explored.

1,392 citations

Journal ArticleDOI
TL;DR: In this paper, a detailed study of semiconductor metal oxide (SMO) gas sensors is provided for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing.
Abstract: This review paper encompasses a detailed study of semiconductor metal oxide (SMO) gas sensors. It provides for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing. Different parameters which affect the performance (sensitivity, selectivity and stability) of SMO gas sensors are discussed here under. This paper also gives an insight about the dopant or impurity induced variations in the SMO materials used for gas sensing. It is concluded that dopants enhance the properties of SMOs for gas sensing applications by changing their microstructure and morphology, activation energy, electronic structure or band gap of the metal oxides. In some cases, dopants create defects in SMOs by generating oxygen vacancy or by forming solid solutions. These defects enhance the gas sensing properties. Different nanostructures (nanowires, nanotubes, heterojunctions), other than nanopowders have also been studied in this review. At the end, examples of SMOs are given to illustrate the potential use of different SMO materials for gas sensing.

1,296 citations