Na1－xZr2－xNbxP3O12系列化合物的水热晶化研究

采用水热晶化反应，制备出传统需要高大相反合成的掺杂，ＮＡＳＩＣＯＮ化合物Ｎａ１－ｘＺｒ２－ｘＮｂｘＰ３Ｏ１２（０＜Ｘ＜１），并应用ＸＲＤ，ＩＲ方法对产物的晶体结构进行了研究。表明水热晶化产物是纯的物相并具有与ＮａＺｒ２Ｐ３Ｏ１２相同的结构，固体＾３１ＰＮＭＲ研究证实Ｎｂ＾５＋部分取代了Ｚｒ＾４＋所在位置，参与骨架的组成，并统计分布于结构中，水热晶化产物与固相反应产物具有相同的离子电导性能。     

Na_（1＋x）Al_xZr_（2－x）P_3O_（12）的水热合成与表征

采用水热法合成了系列磷酸盐化合物Ｎａ_（１＋ｘ）Ａｌ_ｘＺｒ_（２－ｘ）Ｐ_３Ｏ_（１２），该系列化合物具有ＮＡＳＩＣＯＮ型三维骨架结构。考查了反应物料配比、晶化时间、晶化温度等实验条件对产物物相及掺入Ａｌ含量对化合物的结构与性能的影响．实验结果表明：在０≤ｘ≤０．３３的范围内，可水热合成出Ｎａ_（１＋ｘ）Ａｌ_ｘＺｒ_（２－ｘ）Ｐ_３Ｏ_（１２）纯相，而且具有良好的热稳定性。该系列化合物的离子电导率测试结果表明，其电导率与掺入的Ａｌ含量有关。     

二丁胺甲基膦酸锆的苄基季胺化合物及其相转移催化作用

制得了二丁胺甲基膦酸－亚磷酸氢锆Ｚｒ（ＨＰＯ３）２－ｘ．（Ｏ３ＰＣＨ２ＮＢｕ２）．Ｈ２Ｏ（ｘ＝０．８，０．６，０．５，０．４，０．３５），用溴化苄季铵化，得部分季铵化产物，溴化苄基二丁铵甲基膦酸－二丁胺甲基膦酸－亚磷酸氢锆Ｚｒ（ＨＰＯ３）２－ｘ．（Ｏ３ＰＣＨ２ＮＢｕ２）ｘ－ｙ．（Ｏ３ＰＣＨ２Ｎ＾＋Ｂｕ２．ＣＨ２Ｐｈ．Ｂｒ＾－）．Ｈ２Ｏ（ｙ＜ｘ），用作相转移催化剂，对液／液或固／固／液相转移催化的取     

固溶体α－（Fe_（1－x）Sb_x）_2O_3（0≤x≤0．2）气敏材料

用化学共沉淀法在ａ－Ｆｅ＿２Ｏ＿３，中掺入锑离子，Ｘ－射线衍射（ＸＲＤ）分析证实，锑离子可固溶于ｎ型半导体ａ－Ｆｅ＿２Ｏ＿３中形成ａ－（Ｆｅ＿１－ｘＳｂ＿ｘ）＿２Ｏ＿３（０《ｘ《０．２）固溶体。由于锑离子（Ｓｂ￣５＋）部分取代ａ－Ｆｅ＿２Ｏ＿３晶格中Ｆｅ￣３＋的格位，使得该系列材料的电导值增大一个数量级以上，气敏性能明显改善。     

Pr_（2－x）Sr_xNiO_（4±δ）的合成、结构和电磁性质

用固相法合成了Ｐｒ＿（２－ｘ）Ｓｒ＿ｘＮｉＯ＿（４±δ）（０．０≤ｘ≤１．０）系列Ｋ＿２ＮｉＦ＿４型化合物，研究了其结构，红外光谱，电磁性质。当０．０≤ｘ＜０．１和ｘ＝１．０时以正交晶系结晶；当０．１≤ｘ＜１．０时以四方晶系结晶；Ｎｉ离子平均价态在＋２至＋３价之间。当ｘ值较小时，样品中含有过量的氧。ＮｉＯ＿６八面体中Ｎｉ￣（３＋）的Ｊａｈｎ－Ｔｅｌｌｅｒ畸变引起ｃ／ａ值在ｘ＝０．５处出现极大，在７７～２５０Ｋ之间，样品磁性质符合居里－外斯定律，并表现出反铁磁相互作用。电学性质的变化可以理解为Ｎｉ￣（３＋）离子电子组态由：变至的结果     

纳米晶La_（1－_x）Sr_xFeO_3的合成及气敏特性的研究

用柠檬酸盐法合成出Ｌａ_（１－_ｘ）Ｓｒ_ｘＦｅＯ_３（ｘ＝０．１，０．２，０．３，０．４）原粉，再经固相反应得到纳米晶粉末，用ＴＧ、ＤＴＡ、ＸＲＤ、ＩＲ进行了表征，确证复合氧化物Ｌａ_（１－_ｘ）Ｓｒ_ｘＦｅＯ_３为钙钛矿型结构，粒径在１０～２５ｎｍ之间。实验结果表明，随着固相反应条件不同，产物粒径呈规律性变化．气敏特性研究表明，该纳米晶材料对乙醇有较高的选择性和灵敏度，其选择性顺序为Ｌａ_（０．９）Ｓｒ_（０．１）ＦｅＯ_３＞ＬａＦｅＯ_３＞ＬａＦｅＯ_３（大晶粒）。     

SrTi_（1－x）Sn_xO_3的水热合成与结构研究

采用水热晶化法合成出ＳｒＴｉ_（１－ｘ）Ｓｎ_ｘＯ_３系列化合物，并对其结构进行了表征。结果表明，随着Ｓｎ含量的增加，产物的晶胞体积增大，红外吸收谱带发生劈裂，并向高波数方向移动；ＳｒＴｉ_（１－ｘ）Ｓｎ_ｘＯ_３化合物粒度较小，其中常含有少量有机物和吸附水，可以Ｔｉ（ＯＣ４Ｈ９）４为Ｔｉ源直接合成。     

A_2BO_4型催化活性材料结构与性能的研究Ⅰ．［La_（k－x）Sr_x□_（1－k）］_2Cu_（1－y）□_yO_（4－δ）体系

以硝酸盐为原料，用柠檬酸络合法按［Ｌａ１－ｋＳｒｘ□ｋ－ｘ］２ＣｕＯ４（Ｘ＝０、０．０５、０．１、０．１５、０．２，ｋ＝０．０２５）的配比制备了５个样品．应用多晶Ｘ射线衍射法研究了此Ｌａ－Ｓｒ－Ｃｕ－Ｏ系列Ａ２ＢＯ４型复合氧化物的非完整结构．结构研究表明，此系列结构空位型非完整的存在，使结构中Ｂ位的铜离子变价为Ｃｕ２＋和Ｃｕ３＋．但是，随着Ａ位Ｓｒ加入量的增加，Ａ位空位的减少，结构中Ｂ位Ｃｕ３＋量随之减少，Ｃｕ２＋量随之增加，样品对于ＣＯ氧化的催化性能缓慢下降，而ＮＯ还原的催化能力增强．高价态的Ｃｕ３＋的存在是实现对ＣＯ催化氧化的条件；而Ｃｕ２＋给电子能力促进了Ｎｏ－的生成，是ＮＯ催化还原的活性来源．从此系列样品的催化性能和精细结构的研究可得出，适当地调节Ａ２ＢＯ４型结构中Ａ位和Ｂ位的空位及Ｓｒ２＋的掺入量，使Ｂ位Ｃｕ２＋和Ｃｕ３＋保持适当的比例，可获得ＣＯ催化氧化和ＮＯｘ催化还原同时具有较高活性的催化活性材料．     

NdSr_（1－x）M_xNiO_4（M＝Ca，Ba）的合成，结构和电学磁学性

用固相法首次合成了ＮｄＳｒ＿（１－ｘ）Ｍ＿ｘＮｉＯ＿４（Ｍ＝Ｃａ：０．０≤１．０；Ｍ＝Ｂａ：０．０≤ｘ≤０．６）系列复合氧化物，并研究了其结构，红外光谱，电学性质和磁学性质。除ＮｄＣａＮｉＯ以正交晶系结晶外，其它试样的结构均属于四方晶系。ＩＲ谱显示随Ｃａ￣（２＋）离子含量的增加，ＮｄＳｒ＿（１－ｘ）Ｍ＿ｘＮｉＯ＿４的Ｎｉ－Ｏ键缩短，Ｃａ￣（２＋）和Ｂａ￣（２＋）引入ＮｄＳｒＮｉＯ＿４以取代Ｓｒ￣（２＋），使试样由金属性导电转变为半导体性导电；随Ｃａ￣（２＋）含量增加，试样的室温电阻率增大。７７～３００Ｋ磁化率与温度关系曲线显示，所有试样的Ｎｉ￣（３＋）都以低自旋状态存在。     

（Sr，Ba）_（1－x）Eu_xTiO_3的高温高压合成及XPS研究

用高温高压法合成了Ｓｒ１－ｘＥｕｘＴｉＯ３（ｘ＝０．０，０．１，０．２，０．３，０．４，０．５）及Ｂａ０．３Ｅｕ０．７ＴｉＯ３化合物．结果表明，所有样品均为立方结构，样品中存在Ｅｕ（Ⅱ）和Ｅｕ（Ⅲ）的混合价．Ｅｕ３＋的掺入直接影响了Ｓｒ离子与氧离子的结合，使Ｓｒ３ｐ３／２的结合能随ｘ的增加而增加．     

Photophysical and photocatalytic properties of Ca(1-x)BixVxMo(1-x)O4 solid solutions

New solid solutions with the composition of Ca(1-x)BixVxMo(1-x)O4 prepared by a solid-state method were found as novel photocatalysts with enhanced activity for O(2) evolution from aqueous solutions containing sacrificial reagent AgNO3 under visible-light irradiation (>420 nm). The obtained solid solutions crystallized in tetragonal crystal structures, except one of the end compounds, BiVO4, which crystallized in monoclinic structures. The diffuse reflection spectra of the solid solutions shift monotonically to a long wavelength as the ratio of Bi (V) ions to Ca (Mo) ions increases in the solid solution. The band structure and the dependence of the photocatalytic properties were discussed in relation to the solid-solution compositions and photophysical properties.     

掺杂NASICON系统的23Na NMR研究

化合物Na3Zr2Si2PO12。是由ZrO6八面体与SiO4或PO4四面体共角构成的开放三维骨架结构，Na 位于骨架间隙，称之为NASICON（NaSuperIoaicConductor），具有和Na－Al2O3相似的离子电导率（在300℃时，σ＝0．2Ω－1·cm-1［1］但是由于该化合物在100－2000℃间存在单斜一、立方的可逆相变，使其应用受到限制．为了抑制这种相变，已进行了骨架掺杂的研究工作，制备出了多种化学掺杂的NASICON系统［2］．在Na3Zr2Si2PO12化合物中，三个Na十分别位于结构中两个不同的位置，然而掺杂以后，骨架结构发生变化，这时Na十位置，将关系…     

Interaction of Keggin anions of 12-tungstophosphoric acid with Ce(x)Zr(1-x)O2 solid solutions

The interaction of 20 wt% 12-tungstophosphoric acid with Ce(x)Zr(1-x)O(2) solid solutions has been studied by PXRD, FTIR, FT-Raman, H(2)-TPR, NH(3)-TPD, diffuse reflectance UV-vis-NIR, and (31)P MAS NMR techniques. The study indicates that the Keggin anions are attached to Lewis metal ion centres and anion vacancies on Ce(x)Zr(1-x)O(2) supports through WO terminal bonds. The Keggin units at the interface are chemically perturbed as indicated by non-intrinsic IR bands observed at 958 cm(-1) (WO(ter) bond), and 1052, 1102 cm(-1) (PO bond). NH(3)-TPD shows that the Keggin anions fixed to Lewis sites and/or oxygen ion vacancies decrease the ammonia uptake on Ce(x)Zr(1-x)O(2) solid solutions. H(2)-TPR shows modified redox behaviour of Ce(x)Zr(1-x)O(2) solid solutions due to the simultaneous reduction of ceria, decomposition of Keggin anions and the reduction of WO(3). The broadening of (31)P MAS NMR and DR-UV-vis-NIR spectra demonstrate the existence of chemical interactions between the Keggin anions and Ce(x)Zr(1-x)O(2) supports.     

Origin of Thermal Degradation of Sr(2-x)Si(5)N(8):Eu(x) Phosphors in Air for Light-Emitting Diodes

The orange-red emitting phosphors based on M(2)Si(5)N(8):Eu (M = Sr, Ba) are widely utilized in white light-emitting diodes (WLEDs) because of their improvement of the color rendering index (CRI), which is brilliant for warm white light emission. Nitride-based phosphors are adopted in high-performance applications because of their excellent thermal and chemical stabilities. A series of nitridosilicate phosphor compounds, M(2-x)Si(5)N(8):Eu(x) (M = Sr, Ba), were prepared by solid-state reaction. The thermal degradation in air was only observed in Sr(2-x)Si(5)N(8):Eu(x) with x = 0.10, but it did not appear in Sr(2-x)Si(5)N(8):Eu(x) with x = 0.02 and Ba analogue with x = 0.10. This is an unprecedented investigation to study this phenomenon in the stable nitrides. The crystal structural variation upon heating treatment of these compounds was carried out using the in situ XRD measurements. The valence of Eu ions in these compounds was determined by electron spectroscopy for chemical analysis (ESCA) and X-ray absorption near-edge structure (XANES) spectroscopy. The morphology of these materials was examined by transmission electron microscopy (TEM). Combining all results, it is concluded that the origin of the thermal degradation in Sr(2-x)Si(5)N(8):Eu(x) with x = 0.10 is due to the formation of an amorphous layer on the surface of the nitride phosphor grain during oxidative heating treatment, which results in the oxidation of Eu ions from divalent to trivalent. This study provides a new perspective for the impact of the degradation problem as a consequence of heating processes in luminescent materials.     

Study on the reversible electrode reaction of Na(1-x)Ni(0.5)Mn(0.5)O2 for a rechargeable sodium-ion battery

Layered NaNi(0.5)Mn(0.5)O(2) (space group: R ?3m), having an O3-type (α-NaFeO(2) type) structure according to the Delmas' notation, is prepared by a solid-state method. The electrochemical reactivity of NaNi(0.5)Mn(0.5)O(2) is examined in an aprotic sodium cell at room temperature. The NaNi(0.5)Mn(0.5)O(2) electrodes can deliver ca. 105-125 mAh g(-1) at rates of 240-4.8 mA g(-1) in the voltage range of 2.2-3.8 V and show 75% of the initial reversible capacity after 50 charge/discharge cycling tests. In the voltage range of 2.2-4.5 V, a higher reversible capacity of 185 mAh g(-1) is achieved; however, its reversibility is insufficient because of the significant expansion of interslab space by charging to 4.5 V versus sodium. The reversbility is improved by adding fluoroethylene carbonate into the electrolyte solution. The structural transition mechanism of Na(1-x)Ni(0.5)Mn(0.5)O(2) is also examined by an ex situ X-ray diffraction method combined with X-ray absorption spectroscopy (XAS). The staking sequence of the [Ni(0.5)Mn(0.5)]O(2) slabs changes progressively as sodium ions are extracted from the crystal lattice. It is observed that the original O3 phase transforms into the O'3, P3, P'3, and P3" phases during sodium extraction. XAS measurement proves that NaNi(0.5)Mn(0.5)O(2) consists of divalent nickel and tetravalent manganese ions. As sodium ions are extracted from the oxide to form Na(1-x)Ni(0.5)Mn(0.5)O(2), nickel ions are oxidized to the trivalent state, while the manganese ions are electrochemically inactive as the tetravalent state.     

Structural characterization and oxidative dehydrogenation activity of V2O5/Ce(x)Zr(1-x)O2/SiO2 catalysts

The thermal stability of a nanosized Ce(x)Zr(1-x)O2 solid solution on a silica surface and the dispersion behavior of V2O5 over Ce(x)Zr(1-x)O2/SiO2 have been investigated using XRD, Raman spectroscopy, XPS, HREM, and BET surface area techniques. Oxidative dehydrogenation of ethylbenzene to styrene was performed as a test reaction to assess the usefulness of the VOx/Ce(x)Zr(1-x)O2/SiO2 catalyst. Ce(x)Zr(1-x)O2/SiO2 (1:1:2 mol ratio based on oxides) was synthesized through a soft-chemical route from ultrahigh dilute solutions by adopting a deposition coprecipitation technique. A theoretical monolayer equivalent to 10 wt % V2O5 was impregnated over the calcined Ce(x)Zr(1-x)O2/SiO2 sample (773 K) by an aqueous wet impregnation technique. The prepared V2O5/Ce(x)Zr(1-x)O2/SiO2 sample was subjected to thermal treatments from 773 to 1073 K. The XRD measurements indicate the presence of cubic Ce0.75Zr0.25O2 in the case of Ce(x)Zr(1-x)O2/SiO2, while cubic Ce0.5Zr0.5O2 and tetragonal Ce0.16Zr0.84O2 in the case of V2O5/Ce(x)Zr(1-x)O2/SiO2 when calcined at various temperatures. Dispersed vanadium oxide induces more incorporation of zirconium into the ceria lattice, thereby decreasing its lattice size and also accelerating the crystallization of Ce-Zr-O solid solutions at higher calcination temperatures. Further, it interacts selectively with the ceria portion of the composite oxide to form CeVO4. The RS measurements provide good evidence about the dispersed form of vanadium oxide and the CeVO4 compound. The HREM studies show the presence of small Ce-Zr-oxide particles of approximately 5 nm size over the surface of amorphous silica and corroborate with the results obtained from other techniques. The catalytic activity studies reveal the ability of vanadium oxide supported on Ce(x)Zr(1-x)O2/SiO2 to efficiently catalyze the ODH of ethylbenzene at normal atmospheric pressure. The remarkable ability of Ce(x)Zr(1-x)O2 to prevent the deactivation of supported vanadium oxide leading to stable activity in the time-on-stream experiments and high selectivity to styrene are other important observations.     

Polarization Rotation in the Monoclinic Perovskite BiCo(1-x) Fe(x) O(3)

The monoclinic perovskite BiCo(1-x) Fe(x) O(3) (x≈0.7) undergoes a second-order structural transition from tetragonal to monoclinic, which is accompanied by a rotation of the polarization vector from the [001] to [111] directions of a pseudo cubic cell. The crystal structure, determined by electron diffraction and powder synchrotron X-ray diffraction, was the same as that of Pb(Ti(1-x) Zr(x) )O(3) at the morphotropic phase boundary.     

A novel preparation of three-dimensionally ordered macroporous M/Ti (M=Zr or Ta) mixed oxide nanoparticles with enhanced photocatalytic activity

Three-dimensionally ordered macroporous (3 DOM) M/Ti (M=Zr or Ta) mixed oxides were prepared by cohydrolysis of a mixture of Zr(n-OC(4)H(9))(4)/TTIP or TaCl(5)/TTIP (TTIP=titanium isopropoxide) combined with a polystyrene (PS) latex sphere templating technique. The resulting products exhibited homogeneous wall compositions, namely, Zr or Ta was uniformly dispersed into the TiO(2) framework with the loading levels of 5, 10, and 20 mol% for Zr and 2.5, 5.0, and 7.5 mol% for Ta, respectively. The estimated macropore diameter, wall thickness, and particle size of the products ranged from 280 to 290 nm, from 30 to 50 nm, and from 10 to 12 nm, respectively. The products showed only anatase phase structure although their starting solitary metal oxides exhibited suitable crystalline structures under the same preparation conditions. Raman scattering spectroscopy showed that the crystal structure of titania had a slight interference due to the incorporation of Zr or Ta, and UV-vis diffuse reflectance spectroscopy (DRS) showed the narrower band gap of the products compared with that of pure anatase TiO(2). The products exhibited mesoporous wall structures, and their BET surface areas were higher than those of the corresponding pure 3 DOM metal oxides. The UV-light photocatalytic activity of the products was assessed by monitoring the photodegradation of two organic molecules including 4-nitrophenol (4-NP) and rhodamine B (RB). Both the photocatalytic reactions confirmed that the presence of the second metal oxide in the titania framework resulted in enhanced photocatalytic activity compared with the pure titania framework.     

A full interionic potential for Na(1+x)Zr(2)Si(x)P(3-x)O(12) superionic conductors

Most inorganic solids are made up of octahedral and tetrahedral units interconnected to give an infinite framework. Use of computer simulation to study these materials has not been as prevalent as in the organic or biomolecules. Na(1+x)Zr(2)Si(x)P(3-x)O(12) is a typical inorganic solid with ZrO(6) octahedra and (Si/P)O(4) tetrahedra which are shown along with a few Na(+) sites marked M1, M2, and M3. We report here a full interionic potential which reproduces the structure and conductivity of these solids. This augurs well for the study of other inorganic solids.