α-Al2O3纳米粒子对Co-Ni合金异常共沉积电化学行为的影响

为了研究在电化学复合共沉积过程中,惰性纳米粒子和金属离子、电极表面的相互作用,以及由此产生的对合金电化学共沉积行为的影响.本文从两个吸附过程出发: 电解液中的金属离子和H＋在纳米粒子表面的吸附；纳米粒子迁移到阴极表面,在电极表面的吸附.采用Zeta电势和稳态极化以及电化学交流阻抗（EIS）研究了纳米Al2O3粒子和电解液中的金属离子，和电极表面的相互作用,进而分析了纳米粒子对Co2＋和Ni2＋还原沉积的影响规律.通过对阻抗数据的拟合,讨论了Al2O3纳米粒子对等效电路中各物理参数的影响.在H＋和不同金属离子在纳米粒子上发生竞争吸附的基础上,提出了纳米粒子和合金共沉积的可能反应历程.     

镍硫析氢活性阴极的电化学制备及其电催化机理

以硫代硫酸钠作为硫源, 在基本的瓦特浴镀液体系中通过恒电流电沉积方法获得了不同晶体结构的镍硫合金活性阴极. 通过能量散射谱(EDS)、X射线衍射(XRD)以及扫描电子显微镜(SEM)对镀层的化学成分、晶体结构以及表面形貌进行了分析, 并对活性阴极的电催化活性以及析氢过程机理进行了研究. XRD测试结果表明, 随着镀层中硫含量的变化, 镀层的晶体结构呈现出非晶态/Ni3S2混晶和金属间化合物(Ni3S2)两种晶体结构, 其中, 硫含量为33.9%(原子分数)的非晶态/Ni3S2混晶结构的活性阴极在碱性溶液中具有很好的析氢活性, 其优良的析氢活性主要来自于Ni3S2很强的吸附氢能力. 交流阻抗的测试结果表明, Ni3S2金属间化合物的析氢过程只存在一个电化学反应步骤, 而非晶态/Ni3S2混晶镍硫合金活性阴极的析氢过程存在三个电化学反应步骤.     

Zn(Ⅱ)在锌电极上的电沉积机理

在Zn(Ⅱ)-NH_4Cl准中性体系中,采用循环伏安法(CV)研究了Zn~(2+)在锌电极上的反应方式,通过计时电流法(CA)研究了Zn~(2+)沉积的成核方式,利用交流阻抗谱(EIS)考察了不同过电位时Zn~(2+)沉积的阻抗行为。结果表明:Zn~(2+)的电沉积是一个不可逆电极反应,以两步骤单电子串联的方式进行,第一步为速控步;电极反应的电荷传递系数与锌电极的表面结构有关。在恒电位条件下,体系中锌电极上Zn~(2+)的结晶近似于三维瞬时成核方式。Zn~(2+)的沉积经历了覆盖、吸附成膜、大量晶核形成等过程,该过程随着控制电位的负移由电化学极化过渡到电化学极化-浓差极化混合控制阶段。最后给出了Zn~(2+)在锌电极上电沉积过程的机理。     

从2AlCl3/Et3NHCl离子液体中电沉积制备Ni 和Ni-Al 合金

在含Ni2+的2AlCl3/Et3NHCl离子液体中的铜电极上通过恒电位电沉积制备出金属Ni和Ni-Al合金.采用循环伏安和计时电流方法,揭示铜电极上沉积金属Ni的成核机理,研究了电沉积Ni-Al合金的机理,以及恒电位沉积Ni-Al合金工艺条件对沉积Ni-Al合金表面形貌和电流效率的影响.结果表明:在铜电极上电沉积金属Ni的成核机理为受扩散控制的三维瞬时成核过程.在电量≥3.0 C时,电沉积Ni-Al合金的组成基本不再变化.Ni-Al合金的电沉积机理为,Ni的电沉积受扩散控制,同时进行Al的欠电位沉积,在Ni-Al合金电沉积过程中某些Ni-Al合金相的沉积可能受动力学限制而使Ni-Al合金的组成偏离热力学预测结果.在电沉积Ni-Al合金的沉积电流小且平稳,电沉积速率慢条件下,Ni-Al合金表面形貌致密均一,反之就会出现瘤节.电沉积Ni-Al合金的电流效率＞90％.电沉积物的组成接近于Ni3Al合金.     

自掺杂锰基氧化物La1-xMnO3+δ的电化学制备

利用阴极还原恒电位和恒电化学沉积法制备了自掺杂钙钛矿结构的锰基氧化物La1-xMnO3 δ,研究了电解质溶液中La^3 和Mn^2 的物质的量比、沉积电位以及电密度对产物组成的影响,并对电沉积机理和晶格缺陷进行了探讨,结果表明,晶格中的离子空位和Mn^4 的含量是影响体系输运性质的关键。     

Na_3AlF_6-AlF_3熔盐中Ti(Ⅳ)的阴极还原机理

应用循环伏安法和计时电位法研究了在990℃下Na3AlF6-AlF3熔盐中,TiO2钨丝电极上的阴极还原机理.实验表明,Ti(Ⅳ)电沉积过程分两步进行:即首先是Ti(Ⅳ)还原为Ti(Ⅱ),然后Ti(Ⅱ)再还原为金属钛,可表示为:Ti(Ⅳ)→Ti(Ⅱ)→Ti.     

铅上阳极硫酸铅膜的还原过程

采用线性电位扫描法、电位阶跃法, 结合交流阻抗跟踪对铅在4.5mol.dm^-^3H2SO4中-0.6V(vs. Hg/Hg2SO4/4.5mol.dm^-^3H2SO4)极化20min形成的阳极硫酸铅膜的阴极还原进行研究。实验结果表明该膜大部分能被还原, 其中的硫酸铅颗粒先在表面按扩散控制下的三维瞬时成核与生长机理被还原, 然后Pb^2^+自颗粒内径向扩散至已生成的铅层表面上进行还原。颗粒中微粒间的液膜为离子输运的主要途径。     

采用AlCl_3-EMIC-MgCl_2室温离子液体电沉积制备铝-镁合金（英文）

采用恒电流和恒电位技术,以及路易斯酸氯化铝(III)-1-乙基-3-甲基咪唑氯化物离子液体中添加氯化镁(II),室温下在铂和铜阴极表面电沉积制备了铝-镁合金.合金层中镁的含量随离子液体中氯化镁浓度和所施加的阴极电流密度的增加而增加.采用X-射线衍射谱(XRD)、扫描电子显微镜(SEM)和能量散射X-射线谱(EDAX)技术,研究了不同电沉积实验条件得到的电沉积层的晶体结构及表面形貌.增加沉积电流密度,可以制备出致密、光亮和结合力良好的电沉积层.铝-镁合金电沉积的阴极电流效率可达99%.应用电化学石英晶体微天平(EQCM)技术研究了电沉积合金的组成.根据重声阻抗分析得到的质量-电荷(m-Q)曲线斜率计算了金属共沉积层的化学成分.     

水溶液中Ni-La-P合金的电沉积行为

为了开发含稀土的功能材料,我们研究了从水溶液中电沉积Ni-La-P合金工艺[1].刘淑兰等[2]报道了电沉积的Ni-La合金上的阴极析氢行为,但未见Ni-La合金电沉积行为的报道.本文采用动电位扫描法,研究了电沉积Ni-La-P合金过程中,镀液中的配体、H3PO3和Ni2 离子的作用.采用动电位扫描法测量合金电沉积时的阴极极化曲线.所用仪器有DHW型恒电位仪（延边电化学仪器厂）,YEW-TYPE-3086型X-Y函数记录仪（四川仪表四厂）.电极：阴极为1cm2铜片,阳极为5cm2Pt片,参比电极：饱和甘汞电极（SCE）.实验溶液广：NiCl2·6H2O25g/L,NH4Cl9g/L,L1-…     

铭酸溶液中金属铬电沉积的机理

从铬酸溶液中电沉积金属铬的机理曾经有过不少探索.许多研究者认为,阴极表面形成难溶的膜层金属铬的电沉积起着关键性的作用.本文应用交流阻抗谱研究金属铬电沉积过程中阴极表面膜的形成,利用X光电子能谱(XPS)和俄歇电子能谱(AES)分析了表面膜的组成,并且对SO_4~(2-)的作用进行了初步的探讨。     

Laser desorption/ionization and laser ablation synthesis of new selenium oxide compounds from selenium(IV) dioxide

Laser desorption/ionization (LDI) and/or laser ablation (LA) of selenium dioxide crystals or its mixtures with sodium peroxide were studied using a commercial matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer. It was found that LDI and LA of selenium (IV) dioxide not only ionizes SeO(2), but also leads to the formation of several positively and negatively singly charged species: SeO(n) (+) (n = 0-2), Se(2) (+), SeO(n) (-) (n = 0-4), Se(2)O(n) (-) (n = 3-7), Se(3)O(n) (-) (n = 4-9), Se(4)O(n) (-) (n = 8-10). A rather high yield of selenium species in the positive ion mode, Se(m) (+) (m = 1-8) and Se(m)OH(+) (m = 3-7), was obtained by using the MALDI approach while the species detected in the negative ion mode, SeO(n) (-) (n = 0-4), Se(2)O(n) (-) (n = 3-7), Se(3)O(n) (-) (n = 4-9), and Se(4)O(n) (-) (n = 9, 10), were the same as those observed during LDI/LA of selenium dioxide. The addition of sodium peroxide to selenium dioxide with the aim of enhancing its oxidation and thus increasing the production of SeO(4) product resulted in extensive cationization of the species with sodium or potassium. The following positively and negatively charged species were identified: Se(+), Se(2) (+), Se(2)OH(+), Se(2)ONa(+), SeO(n) (-) (n = 0-3), and Se(2)O(n) (-) (n = 0, 1, 4). Also observed in mass spectra of such mixtures, various mixed sodium and/or potassium adducts with selenium oxide species, e.g. Se(2)O(4)K(2)Na(-), were identified. In all, 26 totally new species, Se(2)O(n) (-) (n = 3-6), Se(3)O(n) (-) (n = 4-9), Se(4)O(n) (-) (n = 8-10), Se(4)O(11)H(5) (-), Se(4)O(12)H(3) (-), Se(2)O(4)Na(-), Se(2)O(5)HNa(-), Se(2)O(5)HNa(2) (-), Se(3)O(6)K(2)Na(-), Se(3)O(6)K(2)Na(2) (-), Se(2)ONa(+), and Se(m)OH(+) (m = 3-7), were described for the first time. Also, for the first time, the formation of selenium(IV) diperoxide, O-O-Se-O-O or O(2)SeO(2), is described. The stoichiometries of the compounds generated were confirmed using isotopic pattern modeling.     

大蒜对硒的吸收及硒对大蒜生长的影响

在培养液中添加不同浓度的Ｎａ２ＳｅＯ３研究大蒜对硒的吸收以及吸收的硒对大蒜生长的影响。结果表明，大蒜对硒具有很强的生物富集作用，总硒含量为对照的６２２倍，当添加１ｍｍｏｌ／ＬＮａ２ＳｅＯ３时，有机化程度最主达７８．２４％，另外吸收的硒影响大蒜的生长，低浓度硒促进大蒜生长，１ｍｍｏｌ／ＬＮａ２ＳｅＯ为最适的促进生长浓度，并能提高大蒜中的蛋白质，可溶性糖，ＤＮＡ，ＲＮＡ含量，大蒜可作为补硒和高营养价值     

Laser ablation synthesis of selenium superoxide anion SeO4- via selenium trioxide photolysis. Time-of-flight mass spectrometry and ab initio calculations

Laser desorption/ionisation and laser ablation of solid selenium trioxide, as well as the gas-phase behaviour of selenium trioxide, were studied. Selenium trioxide undergoes photochemical decomposition and, from the mass spectra obtained by laser desorption/ionisation time-of-flight mass spectrometry (LDI-TOF-MS), the following species were identified: O-, O2-, O3-, SeO-, SeO2-, SeO3-, SeO4-, Se2O7-, Se3O11-, and Se4O14-. Formation of the selenium superoxide SeO4- anion is described in this work for the first time. In addition, low-abundance selenium species such as Se2O8H2-, Se3O11H-, and Se4O15H2- were also detected. The stoichiometry of all ions was confirmed via isotopic pattern modeling and/or post-source decay (PSD) analysis. Photolysis of selenium trioxide leads partly to ozone formation. It was found that the most likely mechanisms of selenium superoxide formation are oxidation of selenium trioxide with ozone and/or reactive oxygen radicals, or photolysis of selenium trioxide tetramer (SeO3)4. Therefore, ab initio calculations were performed to support the mass spectrometric evidence and to suggest probable geometries for selenium superoxide anion SeO4- and diselenium superoxide anion Se2O7-, as well as to provide insight into and/or predict possible formation pathways. It has been found that both cyclic and non-cyclic peroxide structures of SeO4- and Se2O7- ions are possible. In addition, the SeO4 structure was also calculated guided by thermodynamic considerations using Gaussian-2 methodology, and the inferred stability of the SeO4 neutral molecule was supported by ab initio calculations.     

Selenium oxoanion compounds of palladium(II)

Three new palladium compounds, PdSeO3, PdSe2O5, and Na2Pd(SeO4)2, containing selenium oxoanions of both Se(IV) and Se(VI) have been prepared under mild hydrothermal conditions. PdSe2O5 and Na2Pd(SeO4)2 both possess one-dimensional structures. Within the structure of PdSe2O5, [PdO4] square planar building blocks are joined together through diselenite, Se2O52-, anions, and form a zigzag chain along the c axis. In Na2Pd(SeO4)2, [PdO4] units are connected by two selenate, SeO42-, anions, and extend along the a axis to form a [Pd(SeO4)2]2- chain. Na+ cations reside in the space between the [Pd(SeO4)2]2- chains and act as counter cations. Unlike above two compounds, PdSeO3 exhibits a layered structure. In the structure of PdSeO3, [PdO4] units are connected to each other by corner-sharing and form a zigzag chain along the b axis. The chains are further joined together by tridentate selenite, SeO32-, anions to form layers in the [ab] plane that stack along the c axis. Crystallographic data: (193 K; Mo Kalpha, lambda=0.71073 A): PdSeO3, monoclinic, space group P21/m, a=3.8884(5) A, b=6.4170(8) A, c=6.1051(7) A, beta=96.413(2) degrees, V=151.38(3) A3, Z=2; PdSe2O5, monoclinic, space group C2/c, a=12.198(2) A, b=5.5500(8) A, c=7.200(1) A, beta=107.900(2) degrees , V=463.8(1) A3, Z=4; Na2Pd(SeO4)2, triclinic, space group P, a=4.9349(11) A, b=5.9981(13) A, c=7.1512 (15) A, alpha=73.894(4) degrees, beta=86.124(4) degrees, gamma=70.834(4) degrees, V=192.03(7) A3, Z=1.     

Three new sodium neptunyl(V) selenate hydrates: structures, Raman spectroscopy, and magnetism

Green crystals of Na(NpO(2))(SeO(4))(H(2)O) (1), Na(3)(NpO(2))(SeO(4))(2)(H(2)O) (2), and Na(3)(NpO(2))(SeO(4))(2)(H(2)O)(2) (3) have been prepared by a hydrothermal method for 1 or evaporation from aqueous solutions for 2 and 3. The structures of these compounds have been characterized by single-crystal X-ray diffraction. Compound 1 is isostructural with Na(NpO(2))(SO(4))(H(2)O) (4). The structure of 1 consists of ribbons of neptunyl(V) pentagonal bipyramids, which are decorated and further connected by selenate tetrahedra to form a three-dimensional framework. The resulting open channels are filled by Na(+) cations and H(2)O molecules. Within the ribbon, each neptunyl polyhedron shares corners with each other solely through cation-cation interactions (CCIs). The structure of 2 adopts one-dimensional [(NpO(2))(SeO(4))(2)(H(2)O)](3-) chains connected by Na(+) cations. Each NpO(2)(+) cation is coordinated by four monodentate SeO(4)(2-) anions and one H(2)O molecule to form a pentagonal bipyramid. The structure of 3 is constructed by one-dimensional [(NpO(2))(SeO(4))(2)](3-) chains separated by Na(+) cations and H(2)O molecules. These chains have two configurations resulting in two disordered orientations of the Se(2)O(4)(2-) tetrahedra. Each NpO(2)(+) cation is coordinated by one bidentate Se(1)O(4)(2-) and three monodentate Se(2)O(4)(2-) anions to form a pentagonal bipyramid. Raman spectra of 1, 2, and 4 were collected on powder samples. For 1 and 4, the neptunyl symmetric stretch modes (670, 676, 730, and 739 cm(-1)) shift significantly toward lower frequencies compared to that in 2 (773 cm(-1)), and there are several asymmetric neptunyl stretch bands in the region of 760-820 cm(-1). Magnetic measurements obtained from crushed crystals of 1 are consistent with a ferromagnetic ordering of the neptunyl(V) spins at 6.5(2) K, with an average low temperature saturation moment of 2.2(1) μ(B) per Np. Well above the ordering temperature, the susceptibility follows Curie-Weiss behavior, with an average effective moment of 3.65(10) μ(B) per Np and a Weiss constant of 14(1) K. Correlations between lattice dimensionality and magnetic behavior are discussed.     

大豆施硒试验研究

大豆叶面喷硒可明显提高籽粒硒含量。鼓粒期一次喷施亚硒酸钠水溶液效果最佳，籽粒硒含量最高可比对照提高31.71倍。叶面喷硒对大豆植株生长及产量无不良影响。     

硒对不同水体致癌因子诱发健康人微核的拮抗作用

采用微核检测技术，研究了亚硒酸钠对启东肝癌高发区不同类型饮用水诱发健康人外周血淋巴细胞微核的拮抗作用。结果表明：（１）各实验水体对细胞的毒性作用，宅沟水〉泯沟水〉自来水〉双蒸水。微核率随着实验水体剂量的增加而升高；（２）１ｍｇ／Ｌ的亚硒酸钠浓度对泯沟水，自来水诱发的微核效应有是显的抑制和／或拮抗作用，呈现明显的剂量－效应关系，提示肝癌高发区饮用水体中确存在与肝癌发病相关的致畸因子，补硒确有防与治原     

细胞动力学研究VIII.Na2SeO3对黑根菌作用特征

The Characteristics of the action of Na2SeO3 on Rhizopus nigrocans has been studied by means of microcalorimetry, the relationship between growth rate constants and the concentration of Na2SeO3 is
k=0.03608exp[-0.003608(c+8.60)2]
It was found that Na2SeO3 of low concentration has promoting action on the growth of Rhizopus nigrocans cells, and high concentration of Na2SeO3 has inhibitory action. The study has provided a lot of information on the bioaffect of selenium and the research of toxicology.     

New mixed metal selenites and tellurites containing Pd2+ ions in a square planar geometry

Four novel mixed metal selenites or tellurites containing PdO(4) squares, namely, BaPd(SeO(3))(2), Bi(2)Pd(SeO(3))(4), and Pb(2)Pd(QO(3))(2)Cl(2) (Q = Se, Te), have been prepared and structurally characterized by single crystal X-ray diffraction analyses. These compounds exhibit three different types of anionic structures. BaPd(SeO(3))(2) contains one-dimensional (1D) [Pd(SeO(3))(2)](2-) anionic chains composed of PdO(4) units linked by SeO(3)(2-) groups in a bidentate bridging fashion. Bi(2)Pd(SeO(3))(4) exhibits a complicated 3D architecture constructed by [Bi(SeO(3))](+) and [Pd(SeO(3))(2)](2-) layers that are alternating along the a-axis. The [Pd(SeO(3))(2)](2-) layers are composed of Pd(2+) ions bridged by SeO(3)(2-) anions in a bidentate fashion. Pb(2)Pd(QO(3))(2)Cl(2) (Q = Se, Te) features zero-dimensional (0D) [Pd(QO(3))Cl(2)](4-) (Q = Se, Te) anionic clusters, which are further bridged by Pb(2+) cations into a 3D network. The results of optical diffuse-reflectance spectrum measurements and band structure calculations based on DFT methods indicate that all the compounds are wide-band-gap semiconductors.