Li1+2x+yAlxNdyTi2-x-ySixP3-xO12系统的锂快离子导体研究

Ｌｉ１＋２ｘ＋ｙＡｌｘＮｄｙＴｉ２－ｘ－ｙＳｉｘＰ３－ｘＯ１２锂快离子导体可以用精选的天然高岭石Ａｌ４「Ｓｉ４Ｏ１０」（ＯＨ）８为起始原料，经与Ｌｉ２Ｃｏ３、ＴｉＯ２、ＮＨ４Ｈ２ＰＯ４进行高温（８００－１０００℃固相反应约２０ｈ而制得，一个空间群属于Ｒ３Ｃ的固溶体导电相可在ｙ＝０．５，ｘ≤０．３和ｙ＝１．０，ｘ≤０．４的组成范围内发现，该盯具有较好的电导性较低的活化能，起始组成ｙ＝１．０，ｘ＝０．     

溶胶—凝胶法合成Li2＋xBxSi1—xO3及其离子导电性能的研究

用溶胶－凝胶法合成了Ｌｉ２＋ｘＢｘＳｉ１－ｘＯ３（ｘ＝０－０．５）,发现形成固溶体的范围是０〈ｘ≤０．２。对其离子导电性的研究发现,当ｘ＝０．３时出现电导率极大值。     

快离子导体Na1＋xZr2—yV0.8ySixP3—xO12系统的制备与电性能研究

Ｎａｓｉｃｏｎ型快离子导体Ｎａ１＋ｘＺｒ２－ｙＭ０．８ｙＳｉｘＰ３－ｘＯ１２系统采用高温固相合成，春合成温度在１３７３Ｋ左右完成，该的合成温度在ｘ不变的情况下，随着ｙ的增大而降低，大多烽合成物为单斜晶系；空间群为Ｃ３／ｃ。当ｙ不变，ｘ增大地基地率的变化是先增大，后减小。最佳导一的起始组成为ｘ＝１．５、ｙ＝０．１，其电导率在室温时为３．２０×１０＾－４Ｓ／ｃｍ，在６７３Ｋ时为６．８８×１０＾－２Ｓ／     

以高岭石和NaTi2（PO4）3为基的钠快离子导体

本文以高岭石为起始原料、以ＮａＴｉ２（ＰＯ４）３为母体结构，通过高温固相反应合成快离子导体Ｎａ１＋２ｘＡｌｘＴｉ２－ｘＳｉｘＰ３－ｘＯ１２系统，并研究了此系统的相组成、结构和电性能．大多数合成反应在１０７３～１２２３Ｋ下完成．在。ｘ＜０．６的组成范围内可形成具有ＮＡＳＩＣＯＮ结构、空间群为Ｃ２／ｃ的固溶体·ｘ射线粉末衍射分析表明随。的增大，系统各合成物的晶胞参数增大．ｘ＝０．４的合成物具有最好的离子电导率，６７３Ｋ时达３．００×１０－３Ｓ／ｃｍ，而激活能为３６．０２ｋＪ／ｍｏｌ．     

稀土含氮黄长石固溶体R2Si3-xAlxO3+xN4-x的X射线衍射研究

用热压和无压烧结工艺，在１７００～１８００℃制备了含氮稀土黄长石固溶体Ｒ２Ｓｉ３－ｘＡｌｘＯ３＋ｘＮ４－ｘ（Ｒ＝Ｎｄ，Ｓｍ，ｘ＝０，０．３，０．６，１．０，１．２；Ｒ＝Ｄｙ，Ｙ，Ｘ＝０，０．３，０．６，１．０；Ｒ＝Ｙｂ，Ｘ＝０，０．３）利用Ｇｕｉｎｉｅｒ－Ｈａｅｇｇ照相法，光密度计在ＬＳ－１８和相应的程序系统（ＳＣＡＮ，ＳＣＡＮＰＩ和ＰＩＲＵＭ）给出了稀土黄长石的Ｘ射线衍射图谱，精密测定了具有不同     

立方A^4＋M^5＋2O7型化合物与新型负热膨胀材料

概述了立方Ａ＾４＋Ｍ＾５＋２Ｏ７型化合物的结构特点，讨论了ＡＶ２－ｘＰｘＯ７型（Ａ＝Ｚｒ或Ｈｆ；ｘ＝０．１～１．２）及其部分取代的Ａ＾４＋１－ｙＢ＾４＋ｙＶ２－ｘＰｘＯ７型（Ｂ＝Ｔｉ，Ｃｅ，Ｔｈ，Ｕ，Ｍｏ，Ｐｔ，Ｐｂ，Ｓｎ，Ｇｅ或Ｓｉ；ｙ＝０．１～０．４）和Ａ＾４＋１－ｙＣ＾１＋ｙＤ＾３＋ｙＶ２－ｘＰｘＯ７型（Ｃ为碱金属元素，Ｄ为稀土金属元素）材料的负热膨胀性能。     

高温燃料电池阴极材料La（Sr）MnO3的电导性能研究

用固相合成法合成了（Ｌａ１－ｘＳｒｘ）１－ｙＭｎＯ３（ｘ＝０～５，ｙ＝０～０．１）单纯相化合物。在空气中用直流四探针法测定了各组成的电导率。测试温度范围为１００～９５０℃。其中（Ｌａ０．７Ｓｒ０．３）０．９５ＭｎＯ３具有最大的电导率。讨论了Ｌａ（Ｓｒ）ＭｎＯ３的电导机理。     

PbTiO_3-Pb(Cd_(1/3)Nb_(2/3))O_3系高温高频压电陶瓷材料的研制

对（１－ｘ）ＰｂＴｉＯ２＋ｘＰｂ（Ｃｄ１／３Ｎｂ２／３）Ｏ３系压电陶瓷材料进行了研究。实验结果指出，当ｘ＝０．１４时，掺入适量的改性添加物ＮｉＯ，ＭｎＯ２，ＷＯ３，经过适当的工艺过程，可得到压电性能优良的高温高频压电陶瓷材料。其中，材料的居里温度Ｔｃ＞４００℃，机械品质因数Ｑｍ＞２０００，机电耦合系数Ｋｔ可达０．４５，介电常数ε小于２１０，是一种很有前途的高温高频压电陶瓷材料。     

Li_2SO_4－Li_2O－P_2O_5体系非晶态Li~＋离子导体的研究

本文给出了非晶态Ｌｉ￣＋离子导体Ｌｉ＿２ＳＯ＿４－Ｌｉ＿ｂＯ－Ｐ＿２Ｏ＿５体系的制备条件、导电性以及差热分析（ＤＴＡ）结果，同时还对其晶化过程进行了研究。结果表明，首先成功地制备出了以Ｌｉ＿２ＳＯ＿４为基质的非晶态离子导电材料，并且在３５０℃时组成为Ｌｉ＿２ＳＯ＿４－０．３０Ｌｉ＿２Ｏ－０．７０Ｐ＿２Ｏ＿５样品的电导率最大（σ＝６．７８×１０￣（－３）Ω￣（－１）ｃｍ￣（－１）），这一结果与ＤＴＡ测量结果取得一致，ＳＥＭ证明是由于非晶母体部分晶化造成的。采用液氮温区急冷技术已成功的将该状态稳定到了室温，稳定后的态再重测其电导率随温度变化关系，相应的电导率提高３０％左右，如果找到某种合适的稳定剂使其一直处于微晶态，将为高电导率离子导体的制备提供一条新路。     

LiNiO2热分解反应动力学研究

用ＤＴＡ和ＸＲＤ研究了ＬｉＮｉＯ_２在空气中的热分解过程为：ＬｉＮｉＯ_２（ｓ）→(６５０～７２０℃)Ｌｉ_２Ｎｉ_８Ｏ_{１０（ｓ）}＋４Ｌｉ_２Ｏ_（ｓ）＋Ｏ_２（ｇ）→(８５０～９５０℃)Ｌｉ_２Ｏ_（ｓ）＋８ＮｉＯ_（ｓ）＋１／２Ｏ_２（ｇ） →(１０００～１１５０℃)ＮｉＯ（ｓ）＋Ｌｉ_２Ｏ_（ｇ）用 Ｄｏｙｌｅ－Ｏｚａｗａ法和 Ｋｉｓｓｉｎｇｅｒ法计算了各反应阶段的表观活化能分别为 ７４７．１８±１．０ ｋＪ·ｍｏｌ^－１、９３２．４６±１．０ ｋＪ·ｍｏｌ^－１和 １１２６．９７±１．０ ｋＪ·ｍｏｌ^－１．用 Ｋｉｓｓｉｎｇｅｒ法确定了反应级数和频率因子,确定了三个阶段的动力学方程分别为 ｄα／ｄt＝１．７３６ｘ１０３９ｅ^{－９００００／Ｔ}（１－α）^{１．０５７}; ｄα／ｄｔ＝１８０６×１０^３９ｅ^{－１１１５００／Ｔ}（１－α）^{０．８４４};ｄα／ｄｔ＝４．２６２×１０４２ｅ^{－１３５０００／Ｔ}（１－α）^{１．２７５}     

H(2)O(2)-sensitized TiO(2)/SiO(2) composites with high photocatalytic activity under visible irradiation

TiO(2)/SiO(2) composite photocatalysts were prepared by depositing of TiO(2) onto nano-SiO(2) particles. X-ray diffraction (XRD), transmission electron micrograph (TEM), Raman spectrometer, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the properties of the synthesized TiO(2)/SiO(2) composites. These results indicated that the products without calcination were amorphous, and calcination could enhance the crystallinity of TiO(2). Increases in the amount of TiO(2) would decrease the dispersion in the composites. H(2)O(2)-sensitized TiO(2)/SiO(2) composite photocatalysts could absorb visible light at wavelength below 550 nm. The photocatalytic activity of as-prepared catalysts was characterized by methyl-orange degradation. The results showed the uncalcined composite photocatalysts with amorphous TiO(2) exhibited higher photocatalytic activity under visible light, and the activity of catalysts with TiO(2) content over 30% decreased with increasing of TiO(2) content. Increases in the calcination temperature and TiO(2) content promote the formation of bulk TiO(2) and result in a decrease in activity.     

Electrical conductivity of (ZrO2)0.85(CeO2)0.12 (Y2O3)0.03

A number of zirconia-based materials show promise as electrode materials in magnetohydrodynamic (MHD) generators. As a part of an exploratory programme to find suitable materials for graded electrode applications in MHD generators, partially stabilized and fully stabilized sintered ceramic materials are prepared and characterized. The oxygen ion transference number t _ion(O^2–) and electrical conductivity of this material are measured up to 1670 K in the oxygen partial pressure range 1 to 10^–6 atm. The activation energies for conduction are determined. The electrical properties of this material are characterized by mixed conduction, ionic and electronic. The observed conductivity data are explained in terms of the defect equilibrium reactions between tetravelent Ce⁴⁺ and trivalent Ce³⁺ ions.     

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.     

Hg(0) oxidative absorption by K(2)S(2)O(8) solution catalyzed by Ag(+) and Cu(2+)

The aqueous phase oxidation of gaseous elemental mercury (Hg(0)) by potassium persulfate (K(2)S(2)O(8), KPS) catalyzed by Ag(+) and Cu(2+) was investigated using a glass bubble column reactor. Concentrations of gaseous Hg(0) and aqueous Hg(2+) were measured by cold vapor generation atomic absorption spectrometry (CVAAS). The effects of several experimental parameters on the oxidation were studied; these include different types of catalysts, pHs and concentrations of potassium persulfate, temperatures, Hg(0) inlet concentrations and tertiary butanol (TBA). The results showed that the removal efficiency of Hg(0) increased with increasing concentration of potassium persulfate and catalysts Ag(+), Cu(2+) and Ag(+) provided better catalytic effect than Cu(2+). For example, in the presence of 5.0mmoll(-1) KPS, the mercury removal efficiency could reach 75.4 and 97.0% for an Ag(+) concentration of 0.1 and 0.3mmoll(-1), respectively, and 69.8 and 81.9% for 0.1 and 0.3mmoll(-1) Cu(2+). On the other hand, high temperature and the introduction of TBA negatively affect the oxidation. Furthermore, the removal efficiency of Hg(0) was much greater in neutral solution than in either acidic or alkaline solution. But the influence of pH was almost eliminated upon the addition of Ag(+) and Cu(2+), and high Hg(0) inlet concentration also has positive impact on the removal efficiency of Hg(0). The possible catalytic oxidation mechanism of gaseous mercury by KPS was also proposed.     

Synthesis and structural study of new potassium uranyl selenates K2(H5O2)(H3O)[(UO2)2(SeO4)4(H2O)2](H2O)4 and K3(H3O)[(UO2)2(SeO4)4(H2O)2](H2O)5

Single crystals of new uranyl selenates K₂(H₅O₂)(H₃O)[(UO₂)₂(SeO₄)₄(H₂O)₂](H₂O)₄ (1) and K₃(H₃O)[(UO₂)₂(SeO₄)₄(H₂O)₂](H₂O)₅ (2) were prepared by isothermal evaporation at room temperature. The crystal structure of 1 was solved by the direct method [C2/c, a = 17.879(5), b = 8.152(5), c = 17.872(5) Å, β = 96.943(5)°, V = 2585.7(19) ų, Z = 4] and refined to R ₁ = 0.0449 (wR ₂ = 0.0952) for 2600 reflections with |F _o| ≥ 4σ _F . The structure of 2 was solved by the direct method [P2₁/c, a = 17.8377(5), b = 8.1478(5), c = 23.696(1) Å, β = 131.622(2)°, V = 2574.5(2) ų, Z = 4] and refined to R ₁ = 0.0516 (wR ₂ = 0.1233) for 4075 reflections with |F _o| ≥ 4σ _F . The structures of 1 and 2 are based on [(UO₂)₂(SeO₄)₄(H₂O)₂]^4? layers. The charge of the inorganic layer is compensated by potassium and oxonium ions arranged in the interlayer space. Each K ion is surrounded by seven O atoms belonging to uranyl selenate layers and water molecules, so that it binds with each other the adjacent uranyl selenate structural elements.     

Dielectric properties of K2Zn2(SO4)3 and (NH4)2 Mg2(SO4)3

Dielectric constant (ɛ), dielectric loss (tan δ) and conductivity (σ) for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ have been measured over the frequency range 100 Hz — 100 kHz and in temperature range 30°C — 400°C. The values of static dielectric constant at room temperature are 7.67 and 4.80 for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ respectively. The plots of log σ against reciprocal temperature at different frequencies of these samples merge into a straight line beyond 250°C and the activation energies calculated in this region are found to be 0.67 eV and 1.98 eV for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ respectively.     

Ferroelectricity in Simple Binary ZrO(2) and HfO(2)

The transition metal oxides ZrO(2) and HfO(2) as well as their solid solution are widely researched and, like most binary oxides, are expected to exhibit centrosymmetric crystal structure and therewith linear dielectric characteristics. For this reason, those oxides, even though successfully introduced into microelectronics, were never considered to be more than simple dielectrics possessing limited functionality. Here we report the discovery of a field-driven ferroelectric phase transition in pure, sub 10 nm ZrO(2) thin films and a composition- and temperature-dependent transition to a stable ferroelectric phase in the HfO(2)-ZrO(2) mixed oxide. These unusual findings are attributed to a size-driven tetragonal to orthorhombic phase transition that in thin films, similar to the anticipated tetragonal to monoclinic transition, is lowered to room temperature. A structural investigation revealed the orthorhombic phase to be of space group Pbc2(1), whose noncentrosymmetric nature is deemed responsible for the spontaneous polarization in this novel, nanoscale ferroelectrics.     

Dumbbell-like PtPd-Fe(3)O(4) Nanoparticles for Enhanced Electrochemical Detection of H(2)O(2)

Dumbbell-like Pt(x)Pd(100-x)-Fe(3)O(4) nanoparticles (NPs) were synthesized and studied for electrocatalytic reduction and sensing of H(2)O(2). In 0.1 M phosphate buffered saline (PBS) solution, the 4-10 nm Pt(x)Pd(100-x)-Fe(3)O(4) NPs showed the Pt/Pd composition-dependent catalysis with Pt(48)Pd(52)-Fe(3)O(4) NPs having the best activity. The Pt(48)Pd(52)-Fe(3)O(4) NPs were tested for H(2)O(2) detection, and their H(2)O(2) detection limit reached 5 nM, which was suitable for monitoring H(2)O(2) generated from Raw 264.7 cells. These dumbbell-like PtPd-Fe(3)O(4) NPs are the most sensitive probe ever reported and can be used to achieve real-time quantitative detection of H(2)O(2) in biological environment for biological and biomedical applications.     

Preparation and characterization of Ti/SnO(2)-Sb(2)O(3)-Nb(2)O(5)/PbO(2) thin film as electrode material for the degradation of phenol

In this work, a novel electrode of titanium substrate coated with mixed metal oxides of SnO(2), Sb(2)O(3), Nb(2)O(5) and PbO(2) was successfully prepared using thermal decomposition and electrodeposition. The surface morphology and the structure of the prepared thin film were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results showed that the structure of the prepared electrode might be described as a Ti/SnO(2)-Sb(2)O(3)-Nb(2)O(5)/PbO(2) thin film and its surface was mainly comprised pyramidal-shape beta-PbO(2) crystals. The modified electrode had higher oxygen evolution potential than that of other PbO(2) modified electrodes. Electrocatalytic oxidation of phenol in aqueous solution was studied to evaluate the potential applications of this electrode in environmental science. The phenol removal efficiency in an artificial wastewater containing 0.50g/L phenol could reach 78.6% at 20 degrees C and pH 7.0 with an applied electricity density of 20mA/cm(2) and treatment time of 120min. When 21.3g/L chloride was added to this wastewater, the removal efficiency could reach to 97.2%.