Xuedong Bai

Technical Institute of Physics and Chemistry, Peping, Beijing, China

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Publications (104)814.87 Total impact


  • No preview · Article · Feb 2016 · ACS Nano
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    Min Zeng · Hao Wang · Chong Zhao · Jiake Wei · Kuo Qi · Wenlong Wang · Xuedong Bai
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    ABSTRACT: A fruitful paradigm in the development of low-cost and efficient water splitting systems for hydrogen generation is to search the highly active non-noble catalysts towards hydrogen evolution reaction (HER). Here, the electrocatalytic HER activity of nanostructured amorphous nickel boride (NiB) alloy has been investigated. Amorphous NiB has exhibited excellent catalytic efficiency and long-term stability for HER over a broad pH range, which is actually comparable to the performance of Pt. This high catalytic activity is due to the amorphous structure and the moderate electron structure of NiB. The NiB catalyst is easily obtained via electroless plating technique and we could get a supported NiB catalyst on desired substrates. Given the low cost, abundance, corrosion resistance, high efficiency and ease of fabrication, amorphous NiB is among the best alternatives to noble metal hydrogen evolution catalysts for water splitting.
    Full-text · Article · Jan 2016 · ChemCatChem
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    ABSTRACT: Monolayer molybdenum disulfide (MoS2) has attracted great interest due to its potential applications in electronics and optoelectronics. Ideally, single-crystal over a large area is necessary to preserve its intrinsic figure of merit but is very challenging to achieve. Here, we report an oxygen-assisted chemical vapor deposition growth of single-crystal monolayer MoS2. We found that the growth of MoS2 domains can be greatly improved by inducing a small amount of oxygen into the growth environment. Triangular monolayer MoS2 domains with sizes up to ~350 μm and a RT mobility up to ~90 cm2/Vs on SiO2, can be achieved. The role of oxygen lies on not only the effective preventing the poisoning of precursors but also the elimination of defects during the growth. Our work provides an advanced method for high-quality single-crystal monolayer MoS2 growth.
    No preview · Article · Dec 2015 · Journal of the American Chemical Society
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    ABSTRACT: The dynamic process of oxygen vacancy migration driven by the external electric field is directly observed at atomic scale in the cerium oxides (CeO2) thin film by in-situ transmission electron microscopy method. When a bias voltage of a proper value is applied across the CeO2 film, the oxygen vacancies are formed near the interface of CeO2/anode, followed by their migration along the direction of the external electric field. The structural modulation occurs in the [110] zone axis due to the ordering of oxygen vacancies. The migration of oxygen vacancies results in the reversible structural transformation, i.e., releasing and storing oxygen processes in CeO2, which is of great significance for the ionic and electronic applications of the cerium oxides materials, such as oxygen pump, gas sensor, resistive random access memory, etc.
    No preview · Article · Nov 2015 · Applied Physics Letters
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    ABSTRACT: An in-depth mechanistic understanding of the electrochemical lithiation process of tungsten oxide (WO3 ) is both of fundamental interest and relevant for potential applications. One of the most important features of WO3 lithiation is the formation of the chemically flexible, nonstoichiometric Lix WO3 , known as tungsten bronze. Herein, we achieved the real-time observation of the deep electrochemical lithiation process of single-crystal WO3 nanowires by constructing in situ transmission electron microscopy (TEM) electrochemical cells. As revealed by nanoscale imaging, diffraction, and spectroscopy, it is shown that the rapid and deep lithiation of WO3 nanowires leads to the formation of highly disordered and near-amorphous Lix WO3 phases, but with no detectable traces of elemental W and segregated Li2 O phase formation. These results highlight the remarkable chemical and structural flexibility of the Lix WO3 phases in accommodating the rapid and deep lithiation reaction.
    No preview · Article · Oct 2015 · Angewandte Chemie International Edition
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    Full-text · Dataset · Sep 2015
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    Min Zeng · Hao Wang · Chong Zhao · Jiake Wei · Wenlong Wang · Xuedong Bai
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    ABSTRACT: The cobalt phosphate-/cobalt borate-based oxygen-evolving catalysts (OECs) are the important class of earth-abundant electrocatalysts that can operate with high activity for water splitting under benign conditions. This article reports the integration of cobalt phosphate (Co-Pi) and cobalt borate (Co-Bi) OECs with three-dimensional (3D) graphene foam (GF) for the electrocatalytic water oxidation reaction. The GF showed a unique advantage to serve as a highly conductive 3D support with large capacity for anchoring and loading Co-OECs, thereby facilitating mass and charge transfer due to the large amount of active sites provided by the 3D graphene scaffold. As a result, this integrated system of GF and Co-OECs exhibits synergistically enhanced catalytic activity. The overpotential (η) of Co-Pi and Co-Bi/graphene catalysts is about 0.390 and 0.315 V in neutral solutions, respectively. Besides, the integrated Co-OECs/graphene catalysts have also exhibited improved and stable oxygen evolution catalytic ability in alkaline solution. © 2015, Science China Press and Springer-Verlag Berlin Heidelberg.
    Full-text · Article · Aug 2015
  • Jiake Wei · Nan Jiang · Jia Xu · Xuedong Bai · Jingyue Jimmy Liu
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    ABSTRACT: We investigated the strong coupling between the excitons of ZnO nanowires (NWs) and the localized surface plasmons (LSPs) of individual Ag nanoparticles (NPs) by monochromated electron energy loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscopy (STEM) instrument. The EELS results confirmed that the hybridization of the ZnO exciton with the LSPs of the Ag NP created two plexcitons: the lower branch plexcitons (LPs) with a symmetrical dipole distribution and the upper branch plexcitons (UPs) with an anti-symmetrical dipole distribution. The spatial maps of the LP and UP excitations reveal the nature of the LSP-exciton interactions. With decreasing size of the Ag NP the peak energies of the LPs and UPs showed a blue-shift and an anti-crossing behavior at the ZnO exciton energy was observed. The coupled oscillator model explains the dispersion curve of the plexcitons and a Rabi splitting energy of ~170 meV was deduced. The high spatial and energy resolution STEM-EELS approach demonstrated in this work is general and can be extended to study the various coupling interactions of a plethora of metal-semiconductor nanocomposite systems.
    No preview · Article · Aug 2015 · Nano Letters
  • Lifen Wang · Zhi Xu · Xuedong Bai · Jianguo Wen · Dean J. Miller

    No preview · Article · Aug 2015 · Microscopy and Microanalysis
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    ABSTRACT: The predicted extraordinary properties of carbon nanotubes (CNTs) from theoretical calculations have great potential for many applications. However, reliable experimental determination of intrinsic properties at the single-tube level is currently a matter of concern, and many challenges remain because of the unhandled and nanoscale size of individual nanotubes. Here, we demonstrated a prototype to detect the intrinsic thermal conductivity of the single-wall carbon nanotube (SWCNT) and verify the significant non-resonant optical absorption behavior on tiny nanotubes by integrating the nanotube and ice into a new core-shell design. In particular, a reversible optical visualization method based on the individual suspended ultra-long SWCNT was first developed by wrapping a nanotube with ice in the cryogenic air environment. The light-induced thermal effect on the hybrid core-shell structure was used to melt the ice shell, which subsequently acted as a temperature sensor to verify the intrinsic thermal conductivity of the core-like nanotube. More interestingly, we successfully determined for the first time the thermal response phenomenon of the tiny absorption cross section in SWCNT in the vertical-polarization configuration and the significant non-resonant absorption behavior in the parallel-polarization configuration. These investigations will provide a better understanding for the unique optical behaviors of CNT and enable the detection of intrinsic properties of various one-dimensional nanostructures such as nanotubes, nanowires, and nanoribbons.
    No preview · Article · Aug 2015 · Light: Science & Applications
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    ABSTRACT: We fabricate carbon nanotube (CNT)-field effect transistors (FETs) with a changeable channel length and investigate the electron transport properties of single-walled, double-walled and triple-walled CNTs under uniaxial strain. In particular, we characterize the atomic structure of the same CNTs in the devices by transmission electron microscopy and correlate the strain-induced electronic property change to the chirality of the CNTs. Both the off-state resistance and on-state resistance are observed to change with the axial strain following an exponential function. The strain-induced band gap change obtained from the maximum resistance change in the transfer curve of the ambipolar FETs is quantitatively compared with the previous theoretical prediction and our DFTB calculation from the chirality of the CNTs. Although following the same trend, the experimentally obtained strain-induced band gap change is obviously larger (57%-170% larger) than the theoretical results for all the six CNTs, indicating that more work is needed to fully understand the strain-induced electronic property change of CNTs.
    Full-text · Article · Jul 2015 · Nanoscale
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    Zhi Zhou · Ying Hu · Xinyan Shan · Wei Li · Xuedong Bai · Pengye Wang · Xinghua Lu

    Full-text · Dataset · Jul 2015
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    Zhi Zhou · Ying Hu · Xinyan Shan · Wei Li · Xuedong Bai · Pengye Wang · Xinghua Lu
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    ABSTRACT: The dynamic structural behavior in DNA due to interaction with cisplatin is essential for the functionality of platinum-based anti-cancer drugs. Here we report a novel method to monitor the interaction progress in DNA-cisplatin reaction in real time with a solid-state nanopore. The interaction processes are found to be well elucidated by the evolution of the capture rate of DNA-cisplatin complex, which is defined as the number of their translocation events through the nanopore in unit time. In the first stage, the capture rate decreases rapidly due to DNA discharging as the positive-charged hydrated cisplatin molecules initially bond to the negative-charged DNA and form mono-adducts. In the second stage, by forming di-adducts, the capture rate increases as DNA molecules are softened, appears as the reduced persistence length of the DNA-cisplatin adducts. In the third stage, the capture rate decreases again as a result of DNA aggregation. Our study demonstrates a new single-molecule tool in exploring dynamic behaviors during drug-DNA reactions and may have future application in fast drug screening.
    Full-text · Article · Jul 2015 · Scientific Reports
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    ABSTRACT: The growth of zigzag single-walled carbon nanotubes (SWNTs) is most challenging among all types of SWNTs, with the highest reported selectivity of ~7%. Here we realized the dominant growth of (16,0) tubes at the abundance near ~80% by using intermetallic W6Co7 catalysts containing plenty amount of (1 1 6) planes together with optimizing the growth conditions. These (1 1 6) planes may act as the structure templates for (16,0) SWNTs due to the geometrical match between the open end of (16,0) tube and the atomic arrangements of the (1 1 6) planes in W6Co7. Using catalysts with designed structure as solid state template at suitable kinetic conditions offers a strategy for selective growth of zigzag SWNTs.
    Full-text · Article · Jun 2015 · Journal of the American Chemical Society
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    ABSTRACT: A lateral piezopotential-gated field-effect transistor is realized by operation of scaning tunneling microscope (STM) tip onto an individual ZnO nanowires inside high-resolution transmission electron microscope (TEM). The electric transport behavior of ZnO nanowires under bending by point contact of STM tip at the cross section of nanowire end shows that, the nanowire conductance decreases up to 2 orders of magnitude when a 2.63% bending strain is applied. Experimental results and their detailed analysis reveal that the regarded change in conductance is not due to Schottky barrier at the contact interface but originates from the carrier depletion caused by the lateral piezoelectric potential within the nanowire. The bending strain-gated transistor is one of the new type piezotronics devices.
    No preview · Article · Apr 2015 · Nano Energy
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    ABSTRACT: The mechanisms of the formation of crystalline materials have been studied for more than a century. Recent discoveries in the self-assembly of many inorganic materials involving aggregation of nanoparticle precursors or pre-nucleation clusters challenge the simple assumptions of classical crystallization theory. The situation for organic materials is even more of a terra incognita due to their high complexity. Using in-situ high-temperature atomic force microscopy (AFM) during the solvent-free crystallization of an organic compound [Ni(quinolone-8-thiolate)2] ([Ni(qt)2]), we have observed long-range migration of nanoparticles on a silica substrate, and their incorporation into larger crystals, suggesting a non-classical pathway in the growth process of the molecular crystal.
    Full-text · Article · Apr 2015 · Journal of the American Chemical Society
  • Zhi Xu · Wenlong Wang · Xuedong Bai

    No preview · Chapter · Feb 2015
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    ABSTRACT: Few-layer graphene was successfully tailored with smooth edges along crystallographic directions by Joule heating-driven tungsten nanoparticles inside a transmission electron microscope. The dynamic process was monitored in real time at the atomic resolution level. These high-resolution in-situ observations show that the neighboring graphene layers joined together to form closed edges, which is in contrast to the supposed open edges formed with hydrogen passivation. The tungsten nanoparticles transformed to W2C in the intermediate stage of etching and to WC after etching, suggesting that carbon dissolution helped the continuous action of the metal nanoparticles in the catalytic anisotropic etching reaction.
    Full-text · Article · Nov 2014 · Nanotechnology
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    ABSTRACT: Using selected-area low-energy electron diffraction analysis, we showed strict orientational alignment of monolayer hexagonal boron nitride (h-BN) crystallites with Cu(100) surface lattices of Cu foil substrates during atmospheric pressure chemical vapor deposition. In sharp contrast, the graphene-Cu(100) system is well-known to assume a wide range of rotations despite graphene's crystallographic similarity to h-BN. Our density functional theory calculations uncovered the origin of this surprising difference: The crystallite orientation is determined during nucleation by interactions between the cluster's edges and the substrate. Unlike the weaker B- and N-Cu interactions, strong C-Cu interactions rearrange surface Cu atoms, resulting in the aligned geometry not being a distinct minimum in total energy. The discovery made in this specific case runs counter to the conventional wisdom that strong epilayer-substrate interactions enhance orientational alignment in epitaxy and sheds light on the factors that determine orientational relation in van der Waals epitaxy of 2D materials.
    Preview · Article · Nov 2014 · Proceedings of the National Academy of Sciences
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    Chong Zhao · Zhi Xu · Hao Wang · Jiake Wei · Wenlong Wang · Xuedong Bai · Enge Wang
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    ABSTRACT: The possibility to induce magnetism in light-element materials that contain only s and p electrons is of fundamental and practical importance. Here, weak high-temperature ferromagnetism is observed in carbon-doped boron nitride (B-C-N) nanosheets. The bulk-quantities of B-C-N nanosheets that are free of metallic impurities are prepared through a multi-step process. These B-C-N samples exhibit ferromagnetic hysteresis stable at room temperature and above, with saturation magnetization and coercivity comparable to the previously reported results of defective graphite samples. The ferromagnetic response disappears upon the removal of carbon dopants from the BN lattice, indicating that the observed magnetism originates from substitutional carbon-doping rather than from extrinsic magnetic impurities. On the basis of first-principle calculations it is shown that not only substitutional carbon doping in a honeycomb BN lattice favors spontaneous spin polarization and local moment formation, but also that the spin moments can exhibit long-range magnetic ordering.
    Full-text · Article · Oct 2014 · Advanced Functional Materials

Publication Stats

3k Citations
814.87 Total Impact Points

Institutions

  • 2008-2015
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 2006-2015
    • Chinese Academy of Sciences
      • • Institute of Physics
      • • State Key Laboratory for Surface Physics
      Peping, Beijing, China
    • Georgia Institute of Technology
      • School of Materials Science and Engineering
      Atlanta, Georgia, United States
    • University of Science and Technology, Beijing
      • School of Materials Science and Engineering
      Beijing, Beijing Shi, China
  • 2014
    • Humboldt-Universität zu Berlin
      Berlín, Berlin, Germany
  • 2012
    • Harbin Institute of Technology
      • Department of Materials Science
      Charbin, Heilongjiang Sheng, China
    • University Town of Shenzhen
      Shen-ch’üan-shih, Zhejiang Sheng, China
  • 2007
    • National Institute for Materials Science
      • International Center for Young Scientist (ICYS)
      Tsukuba, Ibaraki, Japan
    • Wuhan University
      Wu-han-shih, Hubei, China
  • 2004
    • Universität Siegen
      • Institute of Material Science
      Siegen, North Rhine-Westphalia, Germany