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1.
Inorg Chem ; 58(22): 15401-15409, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31674179

RESUMO

A new iron-base superconductor SmFFeAs is synthesized via solid-state metathesis reaction by using SmFCl and LiFeAs as precursors. The compound crystallized in the tetragonal ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters of a = 3.9399(0) Å and c = 8.5034(1) Å. The superconducting diamagnetic transition occurs at 56 K for the parent compound, which confirmed by the resistivity and magnetic susceptibility. The appearance of superconductivity without extrinsic doping could be ascribed to the self-doping owing to the mixed valence of Sm ions. The as-synthesized SmFFeAs serves as a new self-doped parent compound for oxygen-free high-critical-temperature (high-Tc) superconductors.

2.
Dalton Trans ; 48(12): 3819-3824, 2019 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-30806388

RESUMO

FePS3@C nanocomposites are successfully synthesized by a facile two-step route. The as-synthesized samples show excellent thermal and environmental stability. As a novel anode material for lithium batteries, the FePS3@C nanocomposites exhibit a high capacity of 1000 mA h g-1 at a current density of 0.2 A g-1 and excellent reversibility over 100 cycles, indicating their promising applications in lithium storage.

3.
Nanoscale Res Lett ; 13(1): 20, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29335792

RESUMO

Tantalum disulfide nanosheets have attracted great interest due to its electronic properties and device applications. Traditional solution-ased ultrasonic process is limited by ultrasound which may cause the disintegration into submicron-sized flake. Here, an efficient multi-step intercalation and ultrasound-free process has been successfully used to exfoliate 1T-TaS2. The obtained TaS2 nanosheets reveal an average thickness of 3 nm and several micrometers in size. The formation of few-layer TaS2 nanosheets as well as monolayer TaS2 sheets is further confirmed by atomic force microscopy images. The few-layer TaS2 nanosheets remain the 1T structure, whereas monolayer TaS2 sheets show lattice distortion and may adopt the 1H-like structure with trigonal prism coordination.

4.
Nanoscale ; 8(8): 4733-41, 2016 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-26859122

RESUMO

To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ∼3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h g(-1) is achieved at a 1 C rate and is maintained without decay up to 500 cycles (1 C = 1 A g(-1)). Even at the high current density of 5 C and 10 C, the 2D Fe3O4/carbon nanonetworks maintain a reversible capacity of 845 and 647 mA h g(-1) after 500 discharge/charge cycles, respectively. In comparison with other reported Fe3O4-based anodes, the 2D Fe3O4/carbon nanonetwork electrode is one of the most attractive of those in energy storage applications.

5.
Nanoscale Res Lett ; 10(1): 409, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26474890

RESUMO

Titanium oxyhydroxy-fluoride, TiO0.9(OH)0.9F1.2 · 0.59H2O rods with a hexagonal tungsten bronze (HTB) structure, was synthesized via a facile one-step solvothermal method. The structure, morphology, and component of the products were characterized by X-ray powder diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), ion chromatograph, energy-dispersive X-ray (EDX) analyses, and so on. Different rod morphologies which ranged from nanoscale to submicron scale were simply obtained by adjusting reaction conditions. With one-dimension channels for Li/Na intercalation/de-intercalation, the electrochemical performance of titanium oxyhydroxy-fluoride for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) was also studied. Electrochemical tests revealed that, for LIBs, titanium oxyhydroxy-fluoride exhibited a stabilized reversible capacity of 200 mAh g(-1) at 25 mA g(-1) up to 120 cycles in the electrode potential range of 3.0-1.2 V and 140 mAh g(-1) at 250 mA g(-1) up to 500 cycles, especially; for SIBs, a high capacity of 100 mAh g(-1) was maintained at 25 mA g(-1) after 115 cycles in the potential range of 2.9-0.5 V.

6.
Nanoscale Res Lett ; 10(1): 983, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26138451

RESUMO

Porous Zn1 - x Mn x O (x = 0.1, 0.2, 0.44) nanosheets were prepared by a low-cost, large-scale production and simple approach, and the applications of these nanosheets as an anode material for Li-ion batteries (LIBs) were explored. Electrochemical measurements showed that the porous Zn0.8Mn0.2O nanosheets still delivered a stable reversible capacity of 210 mA h g(-1) at a current rate of 120 mA g(-1) up to 300 cycles. These results suggest that the facile synthetic method of producing porous Zn0.8Mn0.2O nanostructure can realize a better cycle durability with stable reversible capacity.

7.
Nanoscale ; 6(3): 1725-31, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24343374

RESUMO

Mn2O3 has been demonstrated to be a promising electrode material for lithium-ion batteries. Thus, the fabrication of Mn2O3 nanomaterials with high specific capacity and cycling stability is greatly desired. Here we report a simple but effective method to synthesis Mn2O3 nanomaterials from a Mn(OH)2 precursor, which was prepared from manganese acetate in ethylene glycol and water at 180 °C for 12 h. The morphology and sheet thickness of Mn(OH)2 precursor could be tuned by controlling the ethylene glycol/H2O volume ratio, resulting in a further tunable morphology and sheet thickness of the porous Mn2O3 nanomaterials. In the electrochemical tests the prepared Mn2O3 nanomaterials, with the porous architecture and thin thickness exhibited a high and stable reversible capacity, indicating that both small thickness and porous sheets structure are crucial for improving the electrochemical performance of Mn2O3 in terms of specific capacity and stability.

8.
Nanoscale Res Lett ; 8(1): 524, 2013 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-24330546

RESUMO

CuGaS2 (CGS) nanoplates were successfully synthesized by one-pot thermolysis of a mixture solution of CuCl, GaCl3, and 1-dodecanethiol in noncoordinating solvent 1-octadecene. Their morphology, crystalline phase, and composition were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. Crystalline structure analysis showed that the as-prepared CGS nanoplates were polytypic, in which the wurtzite phase was interfaced with zincblende domains. The growth process of CGS nanoplates was investigated. It was found that copper sulfide nanoplates were firstly formed and then the as-formed copper sulfide nanoplates gradually transformed to CGS nanoplates with proceeding of the reaction. The optical absorption of the as-synthesized CGS nanoplates was also measured and the direct optical bandgap was determined to be 2.24 eV.

9.
Nanoscale Res Lett ; 8(1): 213, 2013 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-23648261

RESUMO

We have successfully prepared α-Fe2O3 nanospheres by solvothermal method using 2-butanone and water mixture solvent for the first time, which were about 100 nm in diameter and composed of very small nanoparticles. The as-prepared samples were characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the product was α-Fe2O3 nanosphere, and the temperature was an important factor on the formation of α-Fe2O3 nanospheres.

10.
Nanoscale ; 5(4): 1570-5, 2013 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-23329060

RESUMO

In this work, AgInS(2) hierarchical flowerlike nanoarchitectures, which are composed of ultrathin nanowires, were synthesized by thermolysis of a mixed solution of AgNO(3), InCl(3)·4H(2)O and n-dodecanethiol at elevated temperature. The average diameter and length of the nanowires composing the nanoarchitectures can reach 5 nm and ∼300 nm, respectively. We investigated the growth process of the nanoarchitectures and the effects of reaction parameters by XRD, SEM and TEM. In particular, the use of InCl(3)·4H(2)O played a decisive role in the synthesis of the nanoarchitectures. Moreover, it was found that polyhedra formed in the initial reaction time, and then the nanowires grew on the facets of these polyhedra, which resulted in the nanoarchitectures. The reaction temperature and the concentration of metal salts could influence the size of the nanowires.


Assuntos
Cristalização/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos de Prata/síntese química , Índio , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
11.
Nanoscale ; 4(21): 6850-5, 2012 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-23034730

RESUMO

Various CuO nanostructures have been well studied as anode materials for lithium ion batteries (LIBs); however, there are few reports on the synthesis of porous CuO nanostructures used for anode materials, especially one-dimensional (1D) porous CuO. In this work, novel 1D highly porous CuO nanorods with tunable porous size were synthesized in large-quantities by a new, friendly, but very simple approach. We found that the pore size could be controlled by adjusting the sintering temperature in the calcination process. With the rising of calcination temperature, the pore size of CuO has been tuned in the range of ∼0.4 nm to 22 nm. The porous CuO materials have been applied as anode materials in LIBs and the effects of porous size on the electrochemical properties were observed. The highly porous CuO nanorods with porous size in the range of ∼6 nm to 22 nm yielded excellent high specific capacity, good cycling stability, and high rate performance, superior to that of most reported CuO nanocomposites. The CuO material delivers a high reversible capacity of 654 mA h g(-1) and 93% capacity retention over 200 cycles at a rate of 0.5 C. It also exhibits excellent high rate capacity of 410 mA h g(-1) even at 6 C. These results suggest that the facile synthetic method of producing a tunable highly porous CuO nanostructure can realize a long cycle life with high reversible capacity, which is suitable for next-generation high-performance LIBs.


Assuntos
Fontes de Energia Elétrica , Lítio/química , Nanotubos/química , Cobre/química , Técnicas Eletroquímicas , Eletrodos , Porosidade , Temperatura Ambiente
12.
J Nanosci Nanotechnol ; 12(3): 2068-75, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22755022

RESUMO

Bi-based layered materials, at present, serve as the potential candidates for the application of hydrogen storage. In our study, several 3D BiOCl microstructures, such as 2500 nm peonies, 1000 nm ball-flowers, and 3000 nm rough spheres are selectively and solvothermally prepared at 180 degrees C. These microstructures are composed of nanoplate with size of -1000 nm, -300 nm and -200 nm, respectively, the growth surface of which are all (001). Electrochemical hydrogen storage capacities of these microstructures are investigated in Ni/H battery model. It is found that rough spheres could store 0.52 wt% hydrogen related to a discharge capacity of 140 mAh x g(-1) at a current density of 50 mA x g(-1). The hydrogen storage of ball-flowers and peonies is 0.49 wt% (133 mAh x g(-1)) and 0.32 wt% (85 mAh x g(-1)). Brunauer-Emmett-Teller (BET) surface areas of rough spheres, ball-flowers and peonies are 35.0 m2 x g(-1), 33.7 m2 x g(-1), and 19.2 m2 x g(-1), respectively. In addition, the hydrogen storage study of BiOCI microstructure composed of nanoplates with exposed facet perpendicular to [221] axis indicates that hydrogen enters into the interlayer.

13.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 4): i25, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21753922

RESUMO

Lithium calcium niobium oxide (2/1.5/3/10), Li(2)Ca(1.5)Nb(3)O(10), has been synthesized by conventional solid-state reaction. Its structure consists of triple-layer perovskite slabs of corner-sharing NbO(6) octa-hedra inter-leaved with lithium ions; Ca cations partially occupy the perovskite A sites at 75% occupancy probability. All eight atoms in the asymmetric unit are on special positions: one Nb atom has site symmetry 4/mmm; the second Nb, both K, the Sr and two O atoms have site symmetry 4mm; the remaining two O atoms have site symmetries 2mm. and mmm., respectively.

14.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 4): i26, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21753923

RESUMO

Potassium lanthanum titanate(IV), KLaTiO(4), has been synthesized by conventional solid-state reaction. It crystallizes isotypically with the NaLnTiO(4) (Ln = La, Pr, Nd, Sm, Eu, Gd, Y and Lu) family. Five of the six atoms in the asymmetric unit (one K, one La, one Ti and two O atoms) are situated on sites with 4mm symmetry, whereas one O atom has 2mm. site symmetry. The crystal structure can be described as being composed of single layers of distorted corner-sharing TiO(6) octa-hedra extending parallel to (001). The layers are alternately separated by K(+) and La(3+) cations along [001]. The coordination number of both K(+) and La(3+) cations is nine, resulting in distorted KO(9) and LaO(9) polyhedra.

15.
Dalton Trans ; 40(29): 7645-50, 2011 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-21701720

RESUMO

LiCoO(2) concaved cuboctahedra with a size of about 1.0 µm were hydrothermally prepared from CoCO(3) and LiOH·H(2)O at 150 °C. Field-emitting scanning electron microscope (FESEM) images show that the cuboctahedra consisted of four hexagonal plates, with angles of 70.5° in neighboring plates. Electron diffraction (ED) patterns of the hexagonal plates show 1 0 0 diffraction of LiCoO(2) in rhombohedral phase and 2 2 0 diffraction in spinel phase, which means LiCoO(2) concaved cuboctahedra are comprised of two intergrown phases. The electrochemical performance of these concaved cuboctahedra of LiCoO(2) at a rate of 0.5 C demonstrated first run charge/discharge capacities of 155 and 141 mAh g(-1) and a stable discharge capacity of 114 mAh g(-1) after 100 cycles. After that, FESEM images show the LiCoO(2) concaved cuboctahedra have undergone no significant change. At a temperature of 120 °C and under the same conditions, only a small amount of LiCoO(2) concaved cuboctahedron appeared. As the temperature rose to 180 °C, flower-like LiCoO(2) microstructures with a size of about 1.0 µm were formed, constructed of irregular plates. The electrochemical performance of the products prepared at 120 °C and 180 °C indicates lower stability than that of LiCoO(2) concaved cuboctahedra.

17.
Chem Commun (Camb) ; (46): 7185-7, 2009 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-19921024

RESUMO

Monodisperse Cu2WO4(OH)2 round and elliptical hollow spheres have been successfully prepared by a ligand-assisted dissolution process, without any template or surfactant.


Assuntos
Cobre/química , Hidróxidos/química , Compostos Inorgânicos/síntese química , Óxidos/química , Tungstênio/química , Portadores de Fármacos/síntese química , Sistemas de Liberação de Medicamentos , Ligantes , Solubilidade
18.
J Hazard Mater ; 171(1-3): 279-87, 2009 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-19559527

RESUMO

Complex (oxy)fluorides K(2)TiF(6), K(2)TiOF(4), K(3)TiOF(5) and K(7)Ti(4)O(4)F(7) have been successfully synthesized for the first time through a controllable solvothermal route involving different solvents, for example, methanol, methanol-H(2)O and methanol-H(2)O(2). The as-prepared products were characterized by X-ray powder diffraction, N(2) surface area adsorption, scanning electron microscope, Fourier transform infrared spectroscopy, UV-vis absorption spectra and X-ray fluorescence. The influences of reaction conditions such as the ratio of methanol to H(2)O(2) or methanol to H(2)O, reaction temperature on the phase, crystallizability and purity of the (oxy)fluorides products were discussed in detail. Meanwhile, the photocatalytic behaviors of the as-prepared K(2)TiF(6), K(2)TiOF(4), K(3)TiOF(5) and K(7)Ti(4)O(4)F(7) were evaluated by degradation of rhodamine B molecules, and the results showed that all of the products possessed photocatalytic activities in the order of K(2)TiOF(4)>K(2)TiF(6)>K(7)Ti(4)O(4)F(7)>K(3)TiOF(5) at room temperature under the UV light.


Assuntos
Catálise , Fluoretos/química , Fotoquímica/métodos , Adsorção , Peróxido de Hidrogênio/química , Metanol/química , Nitrogênio/química , Rodaminas/química , Solventes/química , Espectrofotometria Ultravioleta/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Temperatura Ambiente , Titânio/química , Água/química , Raios X
19.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 6): i44, 2009 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-21582979

RESUMO

Rubidium dicalcium triniobate(V), RbCa(2)Nb(3)O(10), has been synthesized by solid-state reaction and its crystal structure refined from X-ray powder diffraction data using Rietveld analysis. The compound is a three-layer perovskite Dion-Jacobson phase with the perovskite-like slabs derived by termination of the three-dimensional CaNbO(3) perovskite structure along the ab plane. The rubidium ions (4/mmm symmetry) are located in the inter-stitial space.

20.
Nanotechnology ; 19(6): 065602, 2008 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-21730700

RESUMO

FeC(2)O(4)·2H(2)O nanorods with diameter of about 50 nm and length of up to several micrometers were synthesized at room temperature in a surfactant-assisted system, which was obtained by dissolving bis(2-ethylhexyl)sodium sulfosuccinate (AOT) in a mixed solution composed of water and ethylene glycol (EG). The influence of reaction conditions on the morphology of FeC(2)O(4)·2H(2)O is discussed in detail. Through direct thermal decomposition of FeC(2)O(4)·2H(2)O under different calcination conditions, maghemite (γ-Fe(2)O(3)), magnetite (Fe(3)O(4)) and hematite (α-Fe(2)O(3)) can be selectively obtained, preserving the rod-like morphology. Transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) characterizations showed that the as-obtained iron oxide nanorods were composed of fine particles with different crystal orientations. The magnetic properties of the as-obtained iron oxide nanorods were systematically investigated.

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