Shuo Zhang

Shanghai Institute of Applied Physics, Shanghai, Shanghai Shi, China

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Publications (31)108.26 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A series of ceria supported perovskite-based lean-burn NOx trap (LNT) catalysts 10 wt.% LaCoO3/xK2CO3/CeO2 (denoted as L/xK/C, x = 1, 3, 5, 8 wt.%) were prepared by successive impregnation. They display excellent performance for NOx storage and reduction, especially the one with 3% K2CO3. The formation of supported perovskite LaCoO3 on CeO2 is confirmed by XAFS characterization. The results of XPS and O2-TPD reveal that the supported perovskite LaCoO3 contains considerable amounts of surface adsorbed oxygen, which are responsible for NO to NO2 oxidation during NOx storage. The catalyst L/3K/C exhibits fast and complete NOx trapping in lean condition, showing little NOx leak for long time, over which a particularly high NOx reduction percentage (97.7%) and NOx to N2 selectivity (98.5%) are simultaneously achieved in cyclic lean/rich atmospheres. FT-IR and CO2-TPD results demonstrate the diversity of K species including –OK groups, dispersed surface K2CO3 species and bulk or bulk-like K2CO3 species. The dispersion and states of K species show big impact on NOx storage pathways. In situ DRIFTS results indicate that on L/xK/C NOx is stored as diverse nitrates without evident nitrite species detected during NOx adsorption and storage, which further verifies their excellent oxidation ability.
    Chemical Engineering Journal. 01/2015; 260:357–367.
  • Physical review. B, Condensed matter 09/2014; 90:094107. · 3.77 Impact Factor
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    ABSTRACT: Cu2 MoS4 nanosheets are synthesized by a solvothermal method in which the Cu2 O starting material acts as a sacrificial template. The microstructure of the Cu2 MoS4 nanosheets is characterized at the atomic level, and the growth mechanism is monitored at the nanoscale through systematic time-dependent experiments. As a result, the unprecedented observation of the allotropic phase change in Cu2 MoS4 that occurs during the solvothermal process is possible.
    Small 06/2014; 10(22):4637–4644. · 7.82 Impact Factor
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    ABSTRACT: We report an alternative mechanism for the optical response of an iodine-modified anatase TiO2 photocatalyst material. Unlike the general realization that the iodine atom provides impurity levels within the optical band gap, we suggest that a distorted surface structure plays a dominant role. Anatase pure TiO2 and iodine-modified TiO2 (I-TiO2) nanocrystals were synthesized by a simple solvothermal method, and I-TiO2 exhibited an extended absorption edge up to 550 nm. Employing iodine K-edge X-ray absorption fine structure (XAFS), we demonstrate that iodine is not incorporated into the nanoparticle interior but exists in the form of IO3– groups at the surface. Furthermore, this IO3– cluster adsorption largely induces a disordered structure, as revealed by Ti 2p3/2 X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and Ti K-edge XAFS data fitting. Density functional theory calculation indicates that this distorted structure can form a midgap state, which should be responsible for its excellent optical property. This finding represents a promising route for improving the optical response of the nanophotocatalyst system via surface treatment.
    The Journal of Physical Chemistry C. 06/2014; 118(25):13726–13732.
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    ABSTRACT: The efficient use of natural gas will require catalysts that can activate the first C-H bond of methane while suppressing complete dehydrogenation and avoiding overoxidation. We report that single iron sites embedded in a silica matrix enable direct, nonoxidative conversion of methane, exclusively to ethylene and aromatics. The reaction is initiated by catalytic generation of methyl radicals, followed by a series of gas-phase reactions. The absence of adjacent iron sites prevents catalytic C-C coupling, further oligomerization, and hence, coke deposition. At 1363 kelvin, methane conversion reached a maximum at 48.1% and ethylene selectivity peaked at 48.4%, whereas the total hydrocarbon selectivity exceeded 99%, representing an atom-economical transformation process of methane. The lattice-confined single iron sites delivered stable performance, with no deactivation observed during a 60-hour test.
    Science 05/2014; 344(6184):616-9. · 31.20 Impact Factor
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    ABSTRACT: A non-platinic lean NOx trap catalyst MnOx-K2CO3/K2Ti8O17 (K2CO3 loading: 25 wt %) was prepared via successive impregnation, which exhibits a large NOx storage capacity (3.21 mmol/g), a high NOx reduction percentage (98.5%) and an ultralow selectivity of NOx to N2O (0.3%). The catalyst was characterized by multiple techniques including XRD, SEM/HRTEM, EXAFS, FT-IR, CO2-TPD and in situ DRIFTS. Except for K2O, -OK groups, surface K2CO3 and bulk or bulk-like K2CO3, an unknown titanate phase with a K/Ti atomic ratio higher than 2/8 is identified, which is also active and regenerative for NOx storage and reduction. In-situ DRIFTS results reveal that NOx is mainly stored as bidentate nitrates and bidentate nitrite species in the catalyst. The appearance of negative bands around 1555 and 1575 cm–1 (C═O stretching vibration in bidentate carbonates) suggests the involvement of carbonates in NOx storage. Based upon the characterization results, a carbonate-involved NOx storage/reduction mechanism was proposed.
    Industrial & Engineering Chemistry Research. 05/2014; 53(20):8416–8425.
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    ABSTRACT: We found a direct evidence for the existence of the local chemical Bi–In bonds in the BiIn2 melt. These bonds are strong and prevail, dominating the structure evolution of the intermetallic clusters. From the local structure of the melt-quenched BiIn2 ribbon, the chemical Bi–In bonds strengthen compared with those in the equilibrium solidified alloy. The chemical bonds in BiIn2 melt remain solid during a rapid quenching process. The results suggest that the intermetallic clusters in the melt evolve into the as-quenched intermetallic phase, and the intermetallic phase originates from the chemical bonds between unlike atoms in the melt. The chemical bonds preserve the chemical ordered clusters and dominate the clusters evolution.
    Physics Letters A 05/2014; · 1.63 Impact Factor
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    ABSTRACT: Two CoSiB metallic glasses of low Co contents, which consist of different clusters, have recently been developed by addition of solute atoms. In this work, the atomic structure and the magnetic properties of the two CoBSi metallic glasses were elucidated by state-of-the-art extended X-ray absorption fine structure spectroscopy (EXAFS) combining with ab initio molecular-dynamics (AIMD) computational techniques. Besides, the origin of these magnetic behaviors was discussed in view of the EXAFS results and atomic structures of the metallic glasses.
    Journal of Magnetism and Magnetic Materials 02/2014; · 2.00 Impact Factor
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    ABSTRACT: Local structure inheritance signatures were observed during the alloying process of the Ag50Sn50 melt, using high-temperature X-ray diffraction and ab initio molecular dynamics simulations. The coordination number Nm around Ag atom is similar in the alloy and in pure Ag melts (Nm ∼ 10), while, during the alloying process, the local structure around Sn atoms rearranges. Sn-Sn covalent bonds were substituted by Ag-Sn chemical bonds, and the total coordination number around Sn increases by about 70% as compared with those in the pure Sn melt. Changes in the electronic structure of the alloy have been studied by Ag and Sn K-edge X-ray absorption spectroscopy, as well as by calculations of the partial density of states. We propose that a leading mechanism for local structure inheritance in Ag50Sn50 is due to s-p dehybridization of Sn and to the interplay between Sn-s and Ag-d electrons.
    Journal of Applied Physics 01/2014; 115(4):043506-043506-5. · 2.21 Impact Factor
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    ABSTRACT: Carbon supported Pt–Ni nanoparticles (NPs) electrocatalysts with nominal Pt/Ni atomic ratios of 3:1, 2:1, and 1:1, denoted as Pt3Ni/C, Pt2Ni/C, and Pt1Ni/C, respectively, were obtained by a modified polyol process. The structure of PtnNi/C (n = 3, 2, 1) electrocatalysts was studied by using an X-ray absorption spectroscopy technique combined with X-ray diffraction and transmission electron microscopy. Significantly, the NPs of Pt3Ni/C in air are demonstrated to have a quasi core–shell structure consisting of a core of metallic Pt surrounded by many small NiOx clusters. In contrast, both Pt2Ni/C and Pt1Ni/C are demonstrated to have an alloy structure with partial oxidation on the surface. Under the atmosphere of H2 at 393 K, the PtnNi/C became the expected bimetallic alloy. At last, we discuss the effect of Ni amount on the structure of PtnNi/C and estimate their possible catalytic activity for methanol oxidation reaction. Our results further confirmed that the structure of Pt–Ni NPs can be influenced by Ni amount and this effect may be enlarged by environment effects.
    The Journal of Physical Chemistry C. 10/2013; 117(40):20584–20591.
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    ABSTRACT: We demonstrate that reactions confined within single-walled carbon nanotube (SWCNT) channels are modulated by the metallic and semiconducting character of the hosts. In situ Raman and X-ray absorption near-edge structure spectroscopies provide complementary information about the electronic state of carbon nanotubes and the encapsulated rhenium species, which reveal electronic interactions between encapsulated species and nanotubes. More electrons are transferred from metallic tubes (m-SWCNTs) to oxidic rhenium clusters, leading to a lower valence state rhenium oxide than that in semiconducting tubes (s-SWCNTs). Reduction in 3.5% (vol/vol) H2/Ar leads to weakened host-guest electronic interaction. The high valence state Re within s-SWCNTs is more readily reduced when raising the temperature, whereas only a sluggish change is observed for Re within m-SWCNTs. Only at 400 °C does Re reach a similar electronic state (mixture of Re(0) and Re(4+)) in both types of tubes. Subsequent oxidation in 1% O2/Ar does not show changes for Re in s-SWCNTs up to 200 °C. In comparison, m-SWCNTs facilitate the oxidation of reduced rhenium (160 °C). This can be exploited for rational design of active catalysts with stable species as a desired valence state can be obtained by selecting specific-type SWCNTs and a controlled thermal treatment. These results also provide a chemical approach to modulate reversibly the electronic structure of SWCNTs without damaging the sidewalls of SWCNTs.
    Proceedings of the National Academy of Sciences 08/2013; · 9.81 Impact Factor
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    ABSTRACT: The reactions and structural evolution of FeF3 during cell cycling are investigated in an in situ cell by using Fe K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The results of X-ray absorption near-edge structure spectroscopic analysis demonstrate that there are three stages in the reaction of FeF3 with Li: (1) a two-phase intercalation reaction in the range of x = 0 to 0.46 Li, (2) a single-phase intercalation reaction in the range of x = 0.46 to 0.92 Li, and (3) a conversion reaction in the range of x = 0.92 to 2.78 Li. The coordination numbers (CNs) and bond lengths of the Fe–F bonds or Fe–Fe bonds for the lithiated FeF3 are obtained by performing XAFS fitting. The splitting trends of the Fe–F bond lengths and the Fe–F CNs in the range of x = 0 to 0.92 Li support the proposal that R-3c-structured FeF3 is transformed into R3c-structured Li0.92FeF3 after the intercalation of 0.92 equiv. of Li, and that the intermediate Li0.46FeF3 may be R3-structured. The small Fe–Fe CN of Li2.78FeF3 indicates that the average diameter of the Fe crystallites formed during discharge is <1 nm.
    The Journal of Physical Chemistry C. 05/2013; 117(22):11498–11505.
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    ABSTRACT: A mesoporous perovskite, LaCoO3, with a high specific surface area of 75 m2 g−1 was synthesized by a nano-casting method. Its related NOx storage/reduction catalyst K/LaCoO3, which contains no noble metals, exhibits excellent de-NOx performance under alternating lean/rich conditions, showing a high NOx reduction efficiency of 97.0% and a high NOx to N2 selectivity of 97.3%.
    Catal. Sci. Technol. 04/2013;
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    ABSTRACT: A precipitate was found at the interface between the aqueous phase and the ionic liquid (IL) phase during the separation of UO22+/Eu3+ using irradiated IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides (C4mimNTf2), and was analyzed by SEM, EDS, XPS and PXRD. The anions F- and SO42- were identified as the radiolytic products of C4mimNTf2. The radiation effect on the extraction of UO22+ from aqueous solution by tri-n-butyl phosphate (TBP) in C4mimNTf2 was studied. For the presence of F- and SO42-, the utilization of irradiated C4mimNTf2 as diluent reduced the extraction efficiency of UO22+. The EXAFS measurement showed that the degradation of C4mimNTf2 insignificantly influenced the coordination environment of UO22+ in the IL phase. Furthermore, it was suggested that the complex of uranyl ion with four TBP molecules is predominant during the extraction of UO22+ by TBP in C4mimNTf2 from aqueous solution in the absence of nitric acid. This work gives a further assessment for the application of ILs in the processing of spent nuclear fuel.
    Radiation Physics and Chemistry 02/2013; · 1.38 Impact Factor
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    ABSTRACT: An interesting ensemble of NiOx@Au (i.e. 20–30 nm gold particles partially covered with very small NiOx segments) were clearly identified to be highly active for the low-temperature gas-phase oxidation of alcohols. On such active NiOx@Au ensembles, large amounts of Ni2O3–Au+ hybrid active sites were defined, taking a step closer to identifying the low-temperature activity. By their nature, Ni2O3 specimens not only promote the formation of Au+ ions and stabilize them but also act as an oxygen supplier to transfer oxygen species onto the Au+ sites to react with alcohol.
    Catal. Sci. Technol. 01/2013; 3(2):404-408.
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    ABSTRACT: A high‐resolution X‐ray fluorescence spectrometer based on Rowland circle geometry was developed and installed at BL14W1 XAFS beamline of Shanghai Synchrotron Radiation Facility. The spectrometer mainly consists of three parts: a sample holder, a spherically curved Si crystal, and an avalanche photodiode detector. The simplicity of the spectrometer makes it easily assembled on the general purpose X‐ray absorption beamline. X‐ray emission spectroscopy and high‐resolution X‐ray absorption near edge spectroscopy can be carried out by using this spectrometer. X‐ray emission preliminary results with high‐resolution about 3 eV of Mn compounds were obtained, which confirmed the feasibility of the spectrometer. The application about Eu (III) retention on manganese dioxide was also studied using this spectrometer. Compared with conventional X‐ray absorption fine structure spectroscopy technique, the fluorescence peak of probed element [Eu (III) Lα] and matrix constituents (Mn Kα) were discriminated using this technique, indicating its superiority in fluorescence detection. Copyright © 2013 John Wiley & Sons, Ltd.
    X-Ray Spectrometry 01/2013; 42(6). · 1.55 Impact Factor
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    ABSTRACT: A noble metal (NM) can stabilize monolayer-dispersed surface oxide phases with metastable nature. The formed "oxide-on-metal" inverse catalyst presents better catalytic performance than the NM because of the introduction of coordinatively unsaturated cations at the oxide-metal boundaries. Here we demonstrate that an ultrathin NM layer grown on a non-NM core can impose the same constraint on the supported oxide as the bulk NM. Cu@Pt core-shell nanoparticles (NPs) decorated with FeO patches use much less Pt but exhibit performance similar to that of Pt NPs covered with surface FeO patches in the catalytic oxidation of CO. The "oxide-on-core@shell" inverse catalyst system may open a new avenue for the design of advanced nanocatalysts with decreased usage of noble metals.
    Journal of the American Chemical Society 07/2012; 134(30):12350-3. · 10.68 Impact Factor
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    ABSTRACT: In this research, Mn-doped ZnO nanorods were synthesized by a solvothermal method and their magnetic behavior was tuned from paramagnetism to ferromagnetism via a change in their surface environment. The structure and electronic configuration of Mn ions were investigated by means of X-ray diffraction and X-ray absorption fine structure to understand the surface-controlled magnetic properties. The surface electronic configuration was studied by Mn L3,2-edge XANES, which were simulated using the ligand field multiplet theory and the ligand-to-metal charge transfer effects. The results pointed out that Mn3+ ions occupy distorted tetrahedronal sites near the surface region and different surface modifications produce changes in the Mn 3d-anion p hybridization strength. A midgap state with strong O-2p character has been also recognized at the O K-edge XANES, and the density of such a state is strongly related to the observed ferromagnetism. This research represents a novel promising route for tuning the magnetic behavior of nano-dilute magnetic semiconductor systems via surface atomic changes.
    Chemistry of Materials. 04/2012; 24(9):1676–1681.
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    ABSTRACT: Puzzling magnetic data on the Zn1−xMnxO system such as a small magnetization values or a large negative values of the Curie–Weiss temperature have been obtained in many experimental investigations. Here we report element-specific structural and magnetic investigations on a high-quality Zn0.95Mn0.05O nanocrystalline sample. Combining low-temperature x-ray absorption spectroscopy and theoretical simulations, we show that the formation of substitutional spin-antiparallel pairs induces a large local distortion involving a contraction of the Mn–Mn distance and a reduced Mn–O–Mn bond angle. The first-principles calculation considering hole-doping reveals that such a distortion can result in a localized hole around a dopant atom, generating a ferrimagnetic ordering with a magnetization of 0.45 μB/Mn. This result may give a new insight for a better understanding of the reported magnetic data.
    New Journal of Physics 01/2012; 14(1):013033. · 4.06 Impact Factor
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    ABSTRACT: A dinuclear Cu(II) complex, [Cu(2)(μ-IDA)(phen)(3)(NO(3))]NO(3)·4H(2)O (phen = 1,10-phenanthroline, H(2)IDA = iminodiacetic acid), was found to potently and selectively inhibit T-cell protein tyrosine phosphatase, and lead to the anti-proliferation and apoptosis of C6 glioma cells.
    Chemical Communications 12/2011; 48(8):1153-5. · 6.38 Impact Factor

Publication Stats

49 Citations
108.26 Total Impact Points

Institutions

  • 2011–2014
    • Shanghai Institute of Applied Physics
      Shanghai, Shanghai Shi, China
  • 2010–2013
    • Northeast Institute of Geography and Agroecology
      • • State Key Laboratory of Catalysis
      • • Institute of High Energy Physics
      Beijing, Beijing Shi, China
  • 2012
    • Chinese Academy of Sciences
      • Institute of High Energy Physics
      Beijing, Beijing Shi, China