共查询到20条相似文献,搜索用时 15 毫秒
1.
E. A. Dolgopolova O. S. Ivanova A. B. Shcherbakov N. Ya. Spivak A. E. Baranchikov V. K. Ivanov 《Russian Journal of Inorganic Chemistry》2013,58(11):1287-1293
A method for the synthesis of stable aqueous sols of nanocrystalline solid solutions Ce1?x Gd x O2-δ (x = 0.10, 0.15, 0.20) and Y0.9Eu0.1VO4 and nanocomposites Ce1 ? x Gd x O2-δ/Y0.9Eu0.1VO4 stabilized by biocompatible low-molecular-weight polyacrylic acid was proposed. Polyacrylic acid was shown to be a promising matrix for the preparation of polyfunctional composite materials. 相似文献
2.
A. C. Tavares M. A. M. Cartaxo M.I. da Silva Pereira F. M. Costa 《Journal of Solid State Electrochemistry》2001,5(1):57-67
Studies on the electrochemical behaviour of Ni1−
x
Cu
x
Co2O4 (x ≤ 0.75) and NiCo2−
y
Cu
y
O4 (y ≤ 0.30) electrodes in 5 mol dm−3 KOH aqueous solutions are presented. The oxide layers have been prepared by thermal decomposition of aqueous nitrate solutions
on nickel supports at 623 K. Powder samples were also prepared by thermal decomposition under the same conditions. The powder
samples and the oxide layers were characterised by X-ray powder diffraction. The influence of the copper content on the voltammetric
response of the electrodes and activity towards oxygen evolution reaction is analysed and correlated with the surface composition
of the electrodes by means of X-ray photoelectron spectroscopy data. The analysis of the results reveals that the presence
of Cu affects the electrode behaviour and its influence depends on which cation has been replaced.
Received: 22 February 1999 / Accepted: 26 October 1999 相似文献
3.
《Tetrahedron: Asymmetry》1999,10(10):1969-1977
Pseudomonas cepacia lipase (PSL) efficiently catalyses the kinetic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol through the O-acylation reaction of the corresponding N-benzyloxycarbonyl derivative using vinyl acetate as the acyl donor. In a similar way, cis-N-Cbz-2-aminoindan-1-ol is resolved when isopropenyl acetate is used as the acylating agent. The enantioselectivity of the reaction was lower for (±)-trans-N-Cbz-2-aminoindan-1-ol due to the different steric requirements for the two conformers of this substrate. 相似文献
4.
Kateřina Macounová Jakub Jirkovský Marina V. Makarova Jiří Franc Petr Krtil 《Journal of Solid State Electrochemistry》2009,13(6):959-965
Nanocrystalline Ru1 − x
Ni
x
O2 − y
with 0.02 < x < 0.30 were prepared by a sol–gel approach at temperatures between 300 and 600 °C. XRD patterns of the prepared materials
indicate a single-phase character conforming to a tetragonal syngony. All prepared materials are sufficiently stable in acid
media and show activity towards oxygen evolution. The activity towards oxygen evolution reaction of the materials with constant
chemical composition decreases with increasing particle size. The increasing Ni content enhances the electrocatalytic activity
in a stepwise manner with abrupt changes for materials containing approximately 5% or 15% of the cationic sites substituted
by Ni. 相似文献
5.
Ruby Chauhan Ashavani Kumar Ram Pal Chaudhary 《Research on Chemical Intermediates》2012,38(7):1483-1493
Nanocrystals of undoped and nickel-doped zinc oxide (Zn1?x Ni x O, where x?=?0.00?C0.05) were synthesized by the coprecipitation method. Crystalline size, morphology, and optical absorption of prepared samples were determined by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and UV?Cvisible spectrometer. XRD and SEM studies revealed that Ni-doped ZnO crystallized in hexagonal wurtzite structure. Doping of ZnO with Ni2+ was intended to enhance the surface defects of ZnO. The incorporation of Ni2+ in place of Zn2+ provoked an increase in the size of nanocrystals as compared to undoped ZnO. Crystalline size of nanocrystals varied from 10 to 40?nm as the calcination temperature increased. Enhancement in the optical absorption of Ni-doped ZnO indicated that it can be used as an efficient photocatalyst under visible light irradiation. Optical absorption measurements indicated a red shift in the absorption band edge upon Ni doping. The band gap value of prepared undoped and Ni-doped ZnO nanoparticles decreased as annealing temperature was increased up to 800?°C. 相似文献
6.
N. M. Kozhevnikova 《Russian Journal of Inorganic Chemistry》2014,59(9):992-997
Subsolidus phase ratios in the Na2MoO4-NiMoO4-Sc2(MoO4)3 system have been studied using X-ray diffraction, differential thermal analysis, and vibrational spectroscopy. A phase of variable composition Na1 ? x Ni1 ? x Sc1 + x (MoO4)3 (0 ≤ x ≤ 0.5) having NASICON structure (space group \(R\bar 3c\) ) and a triple molybdate crystallizing in triclinic system (space group \(P\bar 1\) ) have been obtained. The high conductivity of Na1 ? x Ni1 ? x Sc1 + x (MoO4)3 allows the phase of variable composition to be regarded as a promising sodiumion-conductive solid electrolyte. 相似文献
7.
The solid solutions K2Y1?x Tb(Tm) x (MoO4)(PO4) and K2Y1?x Tm x (MoO4)(PO4)0.95(VO4)0.05 were synthesized, which are isostructural and crystallize in the orthorhombic crystal system (space group Ibca). The luminescence intensity of the terbium-containing samples increases with increase in the terbium content. The thulium-containing samples are characterized by intense luminescence in the blue spectral region and concentration quenching of luminescence. The introduction of the vanadate anion adversely affects the luminescence intensity. 相似文献
8.
R. V. Panin N. R. Khasanova A. M. Abakumov W. Schnelle J. Hadermann E. V. Antipov 《Russian Chemical Bulletin》2006,55(10):1717-1722
Sodium ruthenium(III,IV) oxide Na1−x
Ru2O4 was synthesized by the solid state reaction of Na2CO3 and RuO2 in inert atmosphere and characterized by X-ray powder diffraction, electron diffraction, and high-resolution transmission
electron microscopy. The compound crystallizes in the CaFe2O4-type structure (space group Pnma, Z = 4, a = 9.2641(7) Å, b = 2.8249(3) Å, c = 11.1496(7) Å). Double rutile-like chains of the RuO6 octahedra form a three-dimensional framework, whose tunnels contain sodium cations. The structure contains two crystallographically
independent sites of ruthenium atoms randomly occupied by the RuIII and RuIV cations. The superstructure with the doubled b parameter found for one of the samples under study using electron diffraction is caused, probably, by ordering of the Ru
cations in the rutile-like chains. The Na1− x
Ru2O4 compound exhibits temperature-independent paramagnetism with χ0 = 1.9·10−4 cm3 (mole of Ru−1).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1655–1660, October, 2006. 相似文献
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11.
Violeta D. Kassabova-Zhetcheva Lilyana P. Pavlova Bisserka I. Samuneva Zara P. Cherkezova-Zheleva Ivan G. Mitov Mikhail T. Mikhov 《Central European Journal of Chemistry》2007,5(1):107-117
Structural and magnetic properties of Mg
x
Zn1−x
Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mg
x
Zn1−x
Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns
of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes
from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely
small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to
explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts
remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.
相似文献
12.
K. Kammer L. Mikkelsen J. B. Bilde-Sørensen 《Journal of Solid State Electrochemistry》2006,10(11):934-940
(LFN, 0<x<0.6) perovskites were synthesised by a solid-state route and were characterised by powder XRD, dilatometry, four-point DC conductivity measurements and electro-chemical impedance spectroscopy (EIS) on cone-shaped electrodes using a Ce1.9Gd0.1O1.95 (CGO10) electrolyte. All the compounds were of single phase, and they belong to either the cubic or the hexagonal crystal system. The thermal expansion coefficient (TEC) was in the range 10.7*10−6 K−1 to 13.4*10−6 K−1, which continued to increase with increasing nickel content. The highest electronic conductivity was measured for the composition giving a value of 670 S/cm at 380 °C. The highest electro-chemical performance was measured for the composition giving an area specific resistance as low as 5.5 Ωcm2 at 600 °C based on EIS measurements on a cone-shaped electrode. Composite cathodes made from and CGO10 revealed a rather low performance due to an un-optimised micro-structure.
相似文献
K. KammerEmail: Phone: +45-46775835Fax: +45-46775858 |
13.
Vibe L. E. Simonsen Linda Nørskov Kent Kammer Hansen 《Journal of Solid State Electrochemistry》2008,12(12):1573-1577
A series of La2 − x
Sr
x
CuO4 (x = 0.0, 0.05, 0.15, 0.25 and 0.35) compounds was investigated for the use of direct electrochemical reduction of NO in an
all-solid-state electrochemical cell. The materials were investigated using cyclic voltammetry in 1% NO in Ar and 10% O2 in Ar. The most selective electrode material was La2CuO4, which had an activity of NO reduction that was 6.8 times higher than that of O2 at 400 °C. With increasing temperature, activity increased while selectivity decreased. Additionally, conductivity measurements
were carried out, and the materials show metallic conductivity behavior which follows an adiabatic small polaron hopping mechanism. 相似文献
14.
Synthesis and Electrochemical Performance of Spinel LiMn2O4—x(SO4)x Cathode Materials 总被引:1,自引:0,他引:1
IntroductionInrecentyears ,withthedevelopmentofallsortsofcellularphones ,camcorders ,laptopcomputers ,thelithium ionsecondarybatteriesbasedontheuseoflithi um manganese oxideLiMn2 O4 1,2 haveattractedmuchat tention .ButtheLiMn2 O4 cathodematerialhasadisad vantageof… 相似文献
15.
Pet’kov V. I. Shipilov A. S. Fukina D. G. Stenina I. A. Yaroslavtsev A. B. 《Russian Journal of Electrochemistry》2021,57(4):388-394
Russian Journal of Electrochemistry - Vanadate phosphates LiZr2(VO4)x(PO4)3 – x are synthesized by the sol-gel technique with subsequent annealing and studied using X-ray diffraction... 相似文献
16.
《European Journal of Solid State and Inorganic Chemistry #》1998,35(2):173-188
Two synthesis methods for preparing Pr4Ni3O10±δ are compared : a modified sol — gel route and a nitrate — citrate one. It is shown that the autoignition involved in the nitrate — citrate route provides good conditions ressembling the Rapid Thermal Annealing procedure. The oxygen stoichiometry of Pr4Ni3O10±δ phases is measured according to the method of synthesis and thermal treatment. The compounds are metallic as seen by electrical resistivity measurements and thermoelectric power. We show that the adjustment of δ in this series is an important parameter of the transport properties that change from metallic for −0.1 <δ < 0.1 to insulating for Pr4Ni3O8.25. An electronic anomaly is evidenced at 160 K, which intensity is more marked for the stoichiometric Pr4Ni3O10. Our results are consistent with the existence of a charge density wave instability. 相似文献
17.
Lan Liu Ruisong Guo Chao Wang Chao Zhang Yuexia Yang Shanshan Wang 《Journal of Solid State Electrochemistry》2014,18(10):2771-2779
Nickel-substituted layered perovskite PrBaCo2 ? x Ni x O5 + δ (PBCN) powders with various proportions of nickel (x?=?0, 0.1, 0.2, and 0.3, abbreviated as PBCN-0, PBCN-1, PBCN-2, and PBCN-3, respectively) are investigated as potential cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) based on the yttria-stabilized zirconia (YSZ) electrolyte. It is found that PBCN-1 has the highest electrical conductivity of 1,397 S cm?1 at 400 °C. Substitution of Co by Ni decreases the thermal expansion coefficient (TEC) clearly. The average TEC at the temperature range of 35–900 °C decreases from 22.8?×?10?6 K?1 for PBCN-0 to 18.9?×?10?6 K?1 for PBCN-3. The polarization resistances of PBCN samples on YSZ electrolyte at 800 °C are 0.053, 0.048, 0.052, and 0.042 Ω cm2 for PBCN-0, PBCN-1, PBCN-2, and PBCN-3, respectively. The single fuel cell with the configuration of PBCN-3/YSZ/Pt delivers the highest power densities of 100, 185, 360, 495, and 660 mW cm?2 at 600, 650, 700, 750, and 800 °C, respectively. 相似文献
18.
L. S. Aladko 《Russian Journal of General Chemistry》2014,84(6):1065-1068
The phase diagram of the binary system tetramethylammonium bromide-water was studied by the differential thermal analysis. In the stable region two phases, ice and the salt itself, were detected, and in the metastable region, three tetramethylammonium bromide hydrates (bromide-water, 1 : 4, mp 68.8°C, 1 : 5, mp 36.0°C, 1 : 7.5, mp ?19.5°C) were found. Formation of (C x H2x+1)4NBr·nH2O (x = 1–3, n = 4, 5, 7.5) hydrates was revealed. 相似文献
19.
Gd2Zr2O7中Gd具有很大的中子吸收截面, 其烧绿石结构-缺陷萤石结构的转变能较低, 使其成为理想的核废料固化基材. 使用硝酸盐为原料, 添加少量NaF作助熔剂, 在较低温度下(和传统高温固相反应相比), 合成了烧绿石型Gd2Zr2O7. 以Ce4+模拟Pu4+, 研究了Gd2Zr2O7对锕系核素的固化, 并合成了系列模拟固化体(Gd1-xCex)2Zr2O7+x (0≤x≤0.6). 采用粉末X射线衍射(XRD)对系列样品进行了表征. 结果表明: 随着x值的增大,样品从烧绿石结构向缺陷萤石结构转变, 且晶胞大小基本保持恒定, 但当x=0.6时, 衍射峰明显宽化, 晶格畸变比较严重, 晶格稳定性降低. 当x=1时, 即用Ce4+完全取代Gd3+进行合成, 不能得到Ce2Zr2O8, 产物发生了相分离, 为四方结构的(Zr0.88Ce0.12)O2和萤石结构的(Ce0.75Zr0.25)O2的混合物. 模拟固化体的浸出率测试表明: 当x≤0.2时, 各元素浸出率均很低, 但当x≥0.4时, 各元素的浸出率明显升高, 说明以Gd2Zr2O7作为固化Pu4+的基材, Pu4+掺入量不宜高于40%. 相似文献
20.
采用高温固相反应,以NaF作助熔剂,在1000 ℃的温度下合成了锕系元素Pu的模拟固化体(Gd1-xCex)2Zr2O7+x (0 ≤ x ≤ 0.7).研究了模拟固化体的物相、热膨胀系数(TEC)、热导率(TC)随温度及组成的变化规律.粉末X射线衍射(XRD)测试结果表明: Gd2Zr2O7基质本身呈弱有序烧绿石结构,而用Ce4+取代Gd3+的模拟固化体都呈缺陷萤石结构. (Gd1-xCex)2Zr2O7+x的Ce(3d) X射线光电子能谱(XPS)有六个峰,结合能分别位于881.7, 888.1, 897.8, 900.4, 907.1, 916.1 eV处,与CeO2的XPS图谱非常相似,说明Ce为四价.随着温度的升高,所有样品的热膨胀系数总体上呈增大趋势.在室温至750 ℃附近,大部分样品的热导率随温度的升高而降低,之后热导率又呈小幅上升.在相同温度下,固化体(Gd1-xCex)2Zr2O7+x (0 ≤ x ≤ 0.7)的热膨胀系数及热导率随组成变化呈相同趋势:在0 ≤ x ≤ 0.1范围内随x的增大而增大,随后在x = 0.1-0.7时逐渐减小. 相似文献