Mg(IO3)2-H2O体系的一个新物相Mg(IO3)2·2H2O和溶解度-温度相图

在Mg(IO₃)₂-H₂O体系中发现了一个新的物相二水碘酸镁Mg(IO₃)₂·2H₂O.用称重法测定了Mg(IO₃)₂,Mg(IO₃)₂·2H₂O和Mg(IO₂)₂·4H₂O的溶解度随温度变化的曲线。     

草酸铕颗粒微米层状颗粒的合成及其光学性能

在室温条件下, 以柠檬酸钠为辅助剂, 通过简单沉淀法合成了草酸铕Eu₂(C₂O₄)₃·10H₂O微米层状颗粒. 应用X射线衍射、X射线电子能谱、场发射扫描电子显微镜、光致发光光谱对Eu₂(C₂O₄)₃·10H₂O结构与性能进行了表征. 讨论了草酸铕微米层状颗粒可能的形成机理.     

纤维状TiO2/Bi2O3光催化剂的制备及其光催化性能

以C₁₆H₃₆O₄Ti和Bi(NO₃)·5H₂O为原料,以棉花纤维为生物模板,合成了系列纤维状TiO₂/Bi₂O₃光催化剂．采用XRD、SEM、UV-Vis等测试技术对样品的相结构、形貌和吸光性能等进行了表征分析．结果表明,样品中的Bi₂O₃为单斜相和四方相共存的混晶,纤维长度达到毫米级,     

硫酸催化乙二醛气体相水化反应机理和速率常数理论计算研究

采用M06-2X和CCSD(T)高阶量化计算和传统过渡态理论研究硫酸催化乙二醛气体相水化反应.对HCOCHO+H₂O, HCOCHO+H₂O+H₂O, HCOCHO+H₂O+H₂O, HCOCHO+H₂O...H₂SO₄和HCOCHO+H₂O+H₂SO₄五个路径的反应机理和速率常数进行了研究.计算结果表明硫酸具有较强的催化能力,能显著减小乙二醛水化反应的能垒,在CCSD(T)/6-311++G(3df,3pd)//M06-2X/6-311++G(3df,3pd)理论水平,当硫酸分子参与乙二醛水化反应时,反应能垒从37.15 kcal/mol减少至7.08 kcal/mol.在室温条件下,硫酸催化乙二醛水化反应的反应速率1.34×10^-11 cm³/(molecule.s),是等量水分子参与乙二醛水化反应的速率的10¹²倍,大于乙二醛与OH自由基反应的反应速率1.10×10^-11 cm³/(molecule.s).这表明大气条件下,硫酸催化乙二醛水化反应可以发生,同乙二醛与OH自由基反应相竞争.     

氯化苯并咪唑镧的荧光光谱

对新合成的化合物氯化苯并咪唑镧HCl₄·[C₇H₆N₂(H₂O)₂]₂La及其LaCl₃·5H₂O的水溶液进行了三维荧光光谱测定,讨论了HCl₄·[C₇H₆N₂(H₂O)₂]₂La在不同波长的光激发下的荧光特性,荧光强度与浓度的关系及标题化合物的上转换荧光,即在540nm绿光的激发下可以获得紫外光(290nm)和近紫外光(360nm).     

CH3OH在ZnO(0001)表面的光催化解离

本文利用266 nm波长的激光及程序升温脱附的方法研究了甲醇在ZnO(0001)表面的光催化反应. TPD结果显示部分的CH₃OH以分子的形式吸附在ZnO(0001)表面，而另外一部分在表面发生了解离. 实验过程中探测到H₂，CH₃^·，H₂O，CO，CH₂O，CO₂和CH₃OH这些热反应产物. 紫外激光照射实验结果表明光照可以促进CH₃OH/CH₃O^·解离形成CH₂O，在程序升温或光照的过程中它又可以转变为HCOO^-. CH₂OH_Zn与OH_ad反应在Zn位点上形成H₂O分子. 升温或光照都能促进CH₃O^·转变为CH₃^·. 该研究对CH₃OH在ZnO(0001)表面的光催化反应机理提供了一个新的见解.     

硫酸(氢)根吸附层对Pd(111)电极上甲酸氧化反应的影响研究

本文使用循环伏安法和电势阶跃法分别研究了添加和不添加Na₂SO₄的0.1 mol/LH₂SO₄+0.1 mol/LHCOOH溶液中Pd(111)电极上甲酸氧化反应(FAO)的动力学行为，并与同样条件下0.1 mol/LHClO₄中的动力学行为进行比较. 加入0.05 mol/L或者0.1 mol/LNa₂O₄后，在相同的电位下负向扫描的FAO电流比正向扫描的显著减小. 本文推测在(SO₄^*_ad)_m+[(H₂O)_n-H₃O⁺]或(SO₄^*_ad)_m+[Na⁺(H₂O)_n-H₃O⁺]吸附层相转变电势以正的电位, 这个吸附层的结构可能随着电位的增加或Na₂SO₄的加入变得更加致密和稳定. 因此，破坏或者脱附致密的硫酸(氢)根吸附层变得更加困难，使得FAO 动力学在较高电位和随后的负扫电位受到明显的抑制.     

π-(C5H5)2TiCl2·AlR3系可溶性催化剂的电子自旋共振波谱

本文稿研究了Al(iC₄H₉)₃、Al(C₂H₅)₃、Al(C₂H₅)₂Cl、Al(C₂H₅)Cl₂等与π-(C₅H₅)₂TiCl₂所形成的络合物在无溶剂以及在溶剂稀释过程中的电子自旋共振波谱。根据实验结果,作者认为未成对电子是定位在Al²⁷核一端,电子云可延伸到α氢原子位置上,并指出溶剂主要起着分散络合物的作用。     

Li4GeO4-Zn2GeO4赝二元系相图的研究

本文用差热分析和X射线衍射的方法对Li₄GeO₄-Zn₂GeO₄赝二元系相图进行了研究。结果指出,文献中所报道的锂离子导体Li₁₄Zn(GeO₄)₄不是化合物,而是含Zn₂GeO₄的以Li₄GeO₄为基的固溶体,由于Zn₂GeO₄的加入,使Li₄GeO₄的高温相稳定存在于室温。根据研究结果,提出了关于Li₁₄Zn(GeO₄)₄多晶陶瓮样品在室温长期放置后,电导率明显降低的解释。     

石墨炔作为氢气提纯膜

用分子动力学模拟方法研究了石墨炔膜对H₂/O₂、H₂/N₂、H₂/CO和H₂/CH₄混合气体的选择渗透性．在0.047～4.5 GPa的压强下,氢气可以快速穿过石墨炔膜,而所有的O₂、N₂、CO和CH₄分子都被石墨炔膜阻塞．压强为0.047 GPa时,氢气穿过石墨炔膜的流量为7 mol/m²s．氢气流量随着压强的增加而升高,在1.5 GPa下达到峰值6×105 mol/m²s．与其他已知的氢气分离膜相比,模拟结果表明石墨炔可能具有高选择性和高通过性的最好的平衡．     

Dielectric properties of α-zirconium phosphate and its organic derivatives

Dielectric properties of compact discs of α-zirconium phosphate, α-zirconium bis(hydroxymethanephosphonate), in an- hydrous and monohydrated form, and of α-zirconium bis(carboxymethanephosphonate) were investigated, as a function of the temperature, at frequencies ranging from 30 Hz to 100 kHz and, in some cases, up to 2.5 MHz. In all the compounds a low frequency dispersion has been found and ascribed to polarization phenomena due to charge transfer through the compact discs. The comparison of the ?_∞ values of α-Zr(HOOCCH₂PO₃)₂, α-Zr(HPO₄)₂· H₂O and α-Zr(HOCH₂PO₃)₂· H₂O with that of α-zirconium pyrophosphate clearly indicate that orientation polarization is not present in these compounds. The dehydration of α-Zr(HPO₄)₂·H₂O and of α-Zr(HOCH₂PO₃)₂· H₂O is associated with an increment, at low frequency, of the real component of the dielectric constant and with a high frequency dispersion, due to relaxation of orientation polarization. Dielectric properties of α-zirconium phosphate are discussed on the ground of its crystalline structure.     

Protonic conductivity and lithium intercalation in a new iron hydroxyphosphate hydrate: (H3O)[Fe(H2O)]3[H8(PO4)6]·3H2O

A new hydroxonium iron phosphate, (H₃O)[Fe(H₂O)]₃[H₈(PO₄)₆]·3H₂O, was synthesized through a precipitation route by means of acidic media. The crystal structure was solved by X-ray powder diffraction. Electrochemical characterizations, performed on this compound, show reversible intercalation of lithium and substantial lithium diffusion. Protonic conductivity is observed in agreement with the simultaneous presence of H₂O, hydrated protons and OH groups in the large intersecting tunnels of this intersecting tunnel structure.     

Ultrasonic irradiation and its application for improving the corrosion resistance of phosphate coatings on aluminum alloys

In this paper, ultrasonic irradiation was utilized for improving the corrosion resistance of phosphate coatings on aluminum alloys. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effect of ultrasonic irradiation on the corrosion resistance of phosphate coatings was investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Various effects of the addition of Nd₂O₃ in phosphating bath on the performance of the coatings were also investigated. Results show that the composition of phosphate coating were Zn₃(PO₄)₂ · 4H₂O(hopeite) and Zn crystals. The phosphate coatings became denser with fewer microscopic holes by utilizing ultrasonic irradiation treatment. The addition of Nd₂O₃ reduced the crystallinity of the coatings, with the additional result that the crystallites were increasingly nubby and spherical. The corrosion resistance of the coatings was also significantly improved by ultrasonic irradiation treatment; both the anodic and cathodic processes of corrosion taking place on the aluminum alloy substrate were suppressed consequently. In addition, the electrochemical impedance of the coatings was also increased by utilizing ultrasonic irradiation treatment compared with traditional treatment.     

Raman spectroscopic study of the minerals diadochite and destinezite Fe3+2(PO4,SO4)2(OH)· 6H2O: implications for soil science

The two minerals diadochite and destinezite of formula Fe₂(PO₄,SO₄)₂(OH)· 6H₂O have been characterised by Raman spectroscopy and complemented with infrared spectroscopy. Both these minerals are found in soils and are identical except for their morphology. Diadochite is amorphous whereas destinezite is highly crystalline. The spectra of diadochite are broad and ill defined, whereas the spectra of destinezite are intense and well defined. Bands are assigned to phosphate and sulfate stretching and bending modes. Two symmetric stretching modes for both phosphate and sulfate support the concept of non‐equivalent phosphate and sulfate units in the mineral structure. Multiple water bending and stretching modes imply that non‐equivalent water molecules in the structure exist with different hydrogen‐bond strengths. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and aldehyde absorption properties of aspartate-octacalcium phosphate inclusion compound

Double salt of octacalcium phosphate (Ca₈(HPO₄)₂(PO₄)₄·5H₂O; OCP) and aspartate (⁻OOCCH₂CH(NH₂)COO⁻; Asp) was synthesized by hydrolysis of α-tricalcium phosphate (α-Ca₃(PO₄)₂; α-TCP) in the presence of sodium aspartate. The compositional formula of the obtained inclusion compound (Asp-OCP inclusion compound) was Ca₈(HPO₄)_1.28(C₄H₅NO₄)_0.72(PO₄)₄·6.3H₂O, which included higher content of aspartate than that in our precedent paper. Asp-OCP inclusion compound reacted with aldehdyes in the interlayer. In the absorption experiments using formaldehyde gas, the amounts of absorption for Asp-OCP inclusion compound was approximately twice as that for activated charcoal (for Asp-OCP inclusion compound: 3.1×10⁻³ mol/g, activated charcoal: 1.6×10⁻³ mol/g), in spite that the BET specific surface area of Asp-OCP inclusion compound was approximately one-thirtieth part of that of activated charcoal (Asp-OCP inclusion compound: 43 m²/g, activated charcoal: 1225 m²/g). When the gas absorption experiments using acetaldehyde and leaf aldehyde under higher concentrations were carried out, the imine formation in the interlayer were observed in FT-IR and solid state ¹³C-NMR spectra.     

Ionic conductivity of anhydrous zirconium bis(monohydrogen orthophosphate) and its sodium ion forms

Conductivities have been measured by the vector impedance method for the layered compounds anhydrous α-zirconium phosphate, Zr(HPO₄)₂, and several of its sodium ion phases. The values of the ionic diffusion coefficients are of the order of 10^?6-10^?8 cm²/s at 200°C and activation energies range from 15.6 cal/mol for Zr(HPO₄)₂ to 18.6 cal/mol for ZrHNa(PO₄)₂. Comparisons are made with literature values of conductivity and self-diffusion coefficients for Zr(NaPO₄)₂·3H₂O and kinetically determined diffusion coefficients for the phases containing both sodium and hydrogen ions.     

A Raman and infrared spectroscopic study of Ca2+ dominant members of the mixite group from the Czech Republic

The minerals of the mixite group—zálesíite CaCu₆[(AsO₄)₂(AsO₃OH)(OH)₆]·3H₂O from abandoned uranium deposit Zálesí, Czech Republic and calciopetersite CaCu₆[(PO₄)₂(PO₃OH)(OH)₆]·3H₂O from a quarry near Domašov na Bystřicí, northern Moravia, Czech Republic—were studied by Raman and infrared spectroscopy. The observed bands were assigned to the stretching and bending vibrations of (AsO₄)³⁻ and (AsO₃OH)²⁻ ions in zálesíite, and (PO₄)³⁻ and (PO₃OH)²⁻ in calciopetersite, and to molecular water, hydroxyl ions, and Cu‐(O,OH) units in both minerals. O H···O hydrogen‐bond lengths in zálesíite and calciopetersite structures were calculated with Libowitzky's empirical relation. Copyright © 2010 John Wiley & Sons, Ltd.     

On the luminescence of manganese(II) phosphates

Luminescent properties of manganese(II) phosphates prepared by thermal dehydration of Mn(H₂PO₄)₂·2H₂O have been studied. The emission spectrum consists of two bands whose relative intensity and spectral position depend on the chemical and crystalline structure of phosphates. The different courses of temperature quenching of luminescence intensity and excitation spectra of each emission band of Mn(H₂PO₄)₂·2H₂O, Mn(H₂PO₄)₂, MnH₂P₂O₇ and c-Mn₂P₄O₁₂ are discussed.     

The corrosion properties of phosphate coating on AZ31 magnesium alloy: The effect of sodium dodecyl sulfate (SDS) as an eco-friendly accelerating agent

Sodium nitrite has been used as an accelerating agent in phosphating bath to improve its properties. However, it is well known that sodium nitrite is a carcinogenic component in phosphating sludge. In this study, it has been aimed to replace sodium nitrite by an environmentally friendly accelerating agent. To this end, sodium dodecyl sulfate (SDS) was used in phosphating bath to improve the phosphate coating formation on an AZ31 magnesium alloy. The effect of SDS/sodium nitrite ratio on the phosphated samples properties was also studied. Using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) the properties of phosphated magnesium samples were studied.Results showed uniform phosphate coating formation on the magnesium sample mostly in hopeite phase composition. In addition, a denser and less permeable coating can be obtained at these conditions. The corrosion resistance of the phosphated samples was superiorly improved using higher SDS concentration in the phosphating bath.     

Facile Preparation and characterization of zinc phosphate with self-assembled flower-like micro-nanostructures

The three-dimensional flower-like zinc phosphate [Zn₃(PO₄)₂·4H₂O] micro-nanostructures was synthesized by a microwave-assisted sonochemical method in the absence of template under ambient conditions. The effects of reaction temperature of water bath and reactant concentrations on the particle size and morphology of flower-like zinc phosphate were studied. The scanning electron microscopy, transmission electron microscopy, X-ray diffraction and infrared spectroscopy were used to characterize the samples. The results showed that the three-dimensional flower-like zinc phosphate is composed of self-assembled two-dimensional nanosheets. The average thickness of two-dimensional nanosheet was 35–40 nm, and 5–12 layers of nanosheets formed a layered flower with an average thickness of 220–540 nm. The reaction temperatures of water bath and reactant concentrations are the key factors to synthesize perfect three-dimensional flower-like zinc phosphate. The self-assembly is main growth mechanism to form the flower-like zinc phosphate.