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以Na2WO4为钨源,天然土状石墨为碳源,研究二者在高温氩气气氛下的转化过程及规律,利用X射线衍射(XRD)、扫描电子显微镜(SEM)及电子能谱(EDS)对产物进行分析。结果表明,Na2WO4与石墨的混合样品在氩气气氛下经高温处理,可以生成不同的碳钨化合物。首先,石墨与Na2WO4在接触界面发生还原反应,将Na2WO4还原为α-W2C和β-W2C;然后,随着石墨增多,当Na2WO4与石墨的质量比小于1:1时,石墨开始将α-W2C还原为α-WC,直至Na2WO4与石墨的质量比为1:5时,石墨可以将α-W2C完全转化为α-WC。

以彩叶草（ColeusblumeiBenth．）为材料，用营养液培养方法，研究了不同浓度硒（se）处理对浓度为1．0mmol·L-1Pb2＋胁迫下彩叶草根、叶的形貌变化及其组分形态等变化，从光谱学角度初步探讨了硒对重金属铅毒害的缓解机制。结果表明：铅胁迫下的彩叶草根系c、K、ca含量减少，O、Mg、Al、Si、Fe、Pb含量增加，叶片中的C、Mg、Al、si、K、Ca、Fe含量减少，O、Cl含量增加。铅胁迫下硒处理的彩叶草根元素种类及其元素含量均发生了明显变化；根中晶体情况及其晶相也发生了相应变化。

Ultrasonic interferometry was utilized in conjunction with synchrotron-based X-ray diffraction and X-radiographic imaging to determine the compressional and shear wave velocities and unlt-cdl volumes of pyrite （FeS2） at room temperature and pressures up to 9.6 GPa. Fitting all of the experimental volume and velocity data to third-order finite-strain equations yielded the adiabatic zero-pressure bulk and shear moduli and their first pressure derivatives： Ks0=138.9（7） GPa, Go=U2.3（3） GPa, （δKS0/δP）T=KS0＇=6.0（1）, （δG0/δP）T=G0＇=3.0（〈1）, where the numbers in parentheses represent the 1δ uncertainty in the last significant digit. These results are in good agreement with several previous static compression studies on this material but differ quite strongly from the results obtained via first principles calculations. This study presents the first direct measurement of the bulk shear properties of this material.

The complete restoration of a perfect carbon lattice has been a central issue in the research on graphene derived from graphite oxide since this preparation route was first proposed several years ago, but such a goal has so far remained elusive. Here, we demonstrate that the highly defective structure of reduced graphene oxide sheets assembled into free-standing, paper-like films can be fully repaired by means of high temperature annealing （graphitization）. Characterization of the films by X-ray photoelectron and Raman spectroscopy, X-ray diffraction and scanning tunneling microscopy indicated that the main stages in the transformation of the films were （i） complete removal of oxygen functional groups and generation of atomic vacancies （up to 1,500 ~C）, and （ii） vacancy annihilation and coalescence of adjacent overlapping sheets to yield continuous polycrystalline layers （1,800-2,700 ~C） similar to those of highly oriented graphites. The prevailing type of defect in the polycrystalline layers were the grain boundaries separating neighboring domains, which were typically a few hundred nanometers in lateral size, exhibited long-range graphitic order and were virtually free of even atomic-sized defects. The electrical conductivity of the annealed films was as high as 577,000 S-m-1, which is by far the largest value reported to date for any material derived from graphene oxide, and strategies for further improvement without the need to resort to higher annealing temperatures are suggested. Overall, this work opens the prospect of truly achieving a complete restoration of the carbon lattice in graphene oxide materials.

Transition-metal dichalcogenides （TMDs） exhibit immense potential as lithium/ sodium-ion electrode materials owing to their sandwich-like layered structures. To optimize their lithium/sodium-storage performance, two issues should be addressed： fundamentally understanding the chemical reaction occurring in TMD electrodes and developing novel TMDs. In this study, WSe2 hexagonal nanoplates were synthesized as lithium/sodium-ion battery （LIB/SIB） electrode materials. For LIBs, the WSe2-nanoplate electrodes achieved a stable reversible capacity and a high rate capability, as well as an ultralong cycle life of up to 1,500 cycles at 1,000 mA·g^-1. Most importantly, in situ Raman spectroscopy, ex situ X-ray diffraction （XRD）, transmission electron microscopy, and electrochemical impedance spectroscopy measurements performed during the discharge-charge process clearly verified the reversible conversion mechanism, which can be summarized as follows： WSe2 ＋ 4Li^＋ ＋ 4e^- ←→ W ＋ 2Li2Se. The WSe2 nanoplates also exhibited excellent cycling performance and a high rate capability as SIB electrodes. Ex situ XRD and Raman spectroscopy results demonstrate that WSe2 reacted with Na^＋ more easily and thoroughly than with Li^＋ and converted to Na2Se and tungsten in the Ist sodiated state. The subsequent charging reaction can be expressed as Na2Se → Se ＋ 2Na^＋＋ 2e^-, which differs from the traditional conversion mechanism for LIBs. To our knowledge, this is the first systematic exploration of the lithium/sodium-storage performance of WSe2 and the mechanism involved.

Composite Bi@Bi2O3 microspheres have been synthesized via a microwave-assisted solvothermal route. The Bi@Bi2O3 microspheres had a narrow size distribution in the range 1.2-2.8 mm. Glucose was selected as the reductant, BiCl3 as the bismuth source, and ethylene glycol （EG） as the solvent in the synthesis system. The as-synthesized sample was characterized by X-ray diffraction （XRD）, Raman spectroscopy, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, particle diameter distribution, energy dispersive X-ray spectroscopy （EDS）, ultraviolet-visible （UV-vis） spectroscopy, and photoluminescence （PL） spectroscopy. The photocatalytic activities of the Bi@Bi2O3 microspheres were evaluated by the photodegradation of rhodamine B （RhB） and methyl orange （MO） dyes under UV light irradiation. The degradation reached -96.6% for RhB and 100% for MO after 4 h reaction in the presence of the as-synthesized Bi@Bi2O3 microspheres.

One-dimensional ZnMn2O4 nanowires have been prepared and investigated as anode materials in Li rechargeable batteries. The highly crystalline ZnMn2O4 nanowires about 15 nm in width and 500 nm in length showed a high specific capacity of about 650 mAh.g-1 at a current rate of 100 mA.g-1 after 40 cycles. They also exhibited high power capability at elevated current rates, i.e., 450 and 350 mAh.g 1 at current rates of 500 and 1000 mA.g 1, respectively. Formation of Mn3O4 and ZnO phases was identified by ex situ X-ray diffraction （XRD） and transmission electron microscopy （TEM） studies after the initial discharge-charge cycle, which indicates that the ZnMn2O4 phase was converted to a nanocomposite of Mn3O4 and ZnO phases immediately after the electrochemical conversion reaction.

An exhaustive structural analysis was carried out on three Indian coals （ranging from sub-bituminous to high volatile bituminous coal） using a range of advanced characterization tools. Detailed investigations were carded out using UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The tJdC ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak （1585 cm^-1） and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920 cm i are attributed to the symmetric and asymmetric -CH2 stretching vibrations. The intense peak at - 1620 cm^-1, is either attributed to the aromatic ring stretching of C=C nucleus.

Layered double hydroxides （LDHs） are a materials with extensive applications and class of two-dimensional （2D） layered well-developed synthesizing methods in aqueous media. In this work, we introduce an alcohothermal synthesis method for fabricating NiFe-LDHs with dehydrated galleries. The proposed process involves incomplete hydrolysis of urea for the simultaneous precipitation of metal ions, with the resulting water-deficient ethanol environment leading to the formation of a dehydrated structure. The formation of a gallery-dehydrated layer structure was confirmed by X-ray diffraction （XRD）, as well as by a subsequent rehydration process. The methodology introduced here is also applicable for fabricating Fe-based LDHs （NiFe-LDH and NiCoFe-LDH） nanoarrays, which cannot be produced under the same conditions in aqueous media because of the different precipitation processes involved. The LDH nanoarrays exhibit excellent electrocatalytic performance in the oxygen evolution reaction, as a result of their high intrinsic activity and unique structural features. In summary, this study not only introduces a new method for synthesizing LDH materials, but also provides a new route towards highly active and robust electrodes for electrocatalvsis.

Bipyramidal Au microcrystallites have been synthesized by thermalizing a Au-organic complex in the presence of Ag（I） ions, the latter acting as a shape- directing agent. With a highly corrugated morphology leading to strain-induced non-face-centered cubic （non-FCC） Au phases, the non-FCC portion can be tuned by varying the Ag/Au ratio, as verified by diffraction measurements. For a Ag/Au ratio of 0.34, the non-FCC Au portion was as high as 85%. X-ray microdiffraction and electron diffraction measurements reveal that the non-FCC contribution comes primarily from bipyramids, while other microcrystallites, namely, tetrahexahedrons and hexagrams, host non-FCC phases only at the edges and, to an even lesser extent, at the comers. When used as a catalyst for p-nitrophenol reduction, the non-FCC microcrystallites exhibit a significantly enhanced activity compared to FCC Au, which shows only negligible activity. These results are in accordance with trends in the values of two descriptors of reactivity calculated from first principles： The effective coordination number is found to decrease and the d-band center is found to increase in energy going from the FCC to the non-FCC phases of Au. Our findings contradict the general notion that Au is catalytically active only in nanodimensions and is otherwise inert; in this system, its activity arises from the non-FCC phases.