镍钒合金电沉积及其析氢电催化性能的研究

镍钒合金电沉积及其析氢电催化性能的研究林文修王树喜（福建师范大学化学系福州３５０００７）关键词镍钒合金电镀电催化析氢反应对电化学的能量转换、电合成、金属沉积和防腐等具有重要意义，选择和探索优良的过渡金属电催化剂是研究析氢电催化阴极的主要方向。１９７８...     

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.     

镧对非晶／纳米晶Ni-Mo合金镀层结构及性能的影响

在碱性条件下获得了非晶/纳米晶Ni-Mo,Ni-Mo-La丑合金复合镀层,利用X射线衍射(XRD)、扫描电镜(SEM)和电化学分析研究了镧 (La)对获得镀层组织、表面形貌及化学活性的影响.结果表明,随着镧含量的增加,镀层中钼含量升高,形成的Ni-Mo合金的二次相出现α-NiMo,β-Ni4Mo,γ-Ni3Mo和δ-Ni8Mo,同时镀层表面团聚颗粒逐渐分散、细小且致密,镀层表面变得平整光滑.镀层的显微硬度随着La含量的增加先升高后降低.电化学性能实验表明,Ni-Mo-La合金具有良好的电催化性能与合金镀层中的稀土化合物有较高的化学活性有关,其在电解过程中为合金的催化作用提供了活性中心,降低了析氢过电位.     

含稀土的镍基合金的析氢电催化行为

用电沉积方法制备的Ni-Ce-P和Ni-La-P合金作阴极测得析氢阴极极化曲线,结果表明,合金电极上析氢速率比Ni电极上约大10倍,析氢电热政移＞200mV,显示出含稀土的镍基合金具有较高的析氢催化活性,根据XPS谱图讨论了析氢的电催化机制。     

电沉积Ni/LaNiO3复合电极及其在碱性介质中的析氧性能

采用溶胶-凝胶法制备了钙钛矿型复合氧化物LaNiO3,然后将其加入瓦特镀镍液中进行复合电沉积,研究了镀液pH值和阴极电流密度对Ni/LaNiO3复合镀层组成的影响。运用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)等对复合镀层进行表征,结果表明:最佳电沉积工艺条件是镀液pH=5.8和阴极电流密度jk=90 mA.cm-2,所得的Ni/LaNiO3复合镀层中LaNiO3的质量含量约为60%。用循环伏安、稳态极化、恒电位阶跃、电化学阻抗谱等电化学技术评价了Ni/LaNiO3复合电极的析氧性能。结果表明:在5 mol.L-1的KOH溶液中,Ni/LaNiO3复合电极的起始析氧电位较镍电极负,表观活化自由能比镍电极降低约2/3,比表面积约为镍电极的55倍,析氧电催化性能得到大幅度提高。     

单一稀土镧在不同基底上的电沉积及其性能的研究

研究在低温熔融盐体系中于不同基底上电沉积单一稀土金属镧（La）。经X-射线能谱仪测定,在镍片基底上沉积的La的质量分数为100％,铜片基底上沉积的La质量分数为72．84％;在镍铁合金灯丝上沉积得到La-Ni合金薄膜,其中La的质量分数为50．02％,Ni的质量分数为2．48％。经扫描电子显微镜观察,所得的沉积膜为均匀、光滑、致密的黑色沉积薄膜。经X-射线衍射仪分析,镧在不同基底上沉积所得的沉积膜为不同晶型,以镍片为基底得到的单质镧为α-六方晶型;以铜片为基底得到的单质镧为面心立方晶;均与基底晶型相匹配。在镍铁合金灯丝上电沉积所得的La-Ni合金薄膜致密均匀,在无水乙醇中久浸而不脱落,并呈现强磁性。     

Ni-Co-LaNi5复合电极材料在碱性介质中的电催化析氢性能

电催化析氢反应是电能向化学能转化的一个有效途径,是电化学科学中一个非常值得深入研究的课题。阴极析氢超电势的降低,是提高析氢活性,降低电解能耗的关键。为了提高电极的电催化活性,一是可通过提高电极表面的真实表面积,来降低电解过程中电极表面的真实电流密度,达到降低析氢超电势的目的;另一发展方向是提高电极材料本身的电化学活性,即寻找高催化活性的新型析氢材料犤1犦。由于过渡金属具有特殊的d电于结构,是目前公认的电化学活性最好的电极材料,而在过渡金属中,Ni及Ni合金将是研究的主要方向,其中多元合金复合材料将成为该技术发展…     

电沉积纳米镍合金在海水溶液中的析氢性能

采用电沉积法获得Ni、Ni-Fe和Ni-Fe-C合金镀层电极, 在90 °C模拟海水(0.5 mol·L-1 NaCl, pH=12)的稳态极化曲线表明Ni-Fe-C合金电极具有最好的析氢催化性能. 通过扫描电子显微镜(SEM)观察电极表面形貌、X射线衍射(XRD)与透射电子显微镜(HRTEM)分析合金的晶体结构, 发现电极材料的晶粒尺寸影响析氢催化性能, 晶粒尺寸越小析氢催化活性越好. 用电化学阻抗方法(EIS)研究电极析氢催化性能的本质原因, 结果表明电极表面活性点数目和电极的本质电催化活性对合金电极析氢催化活性有重要的影响.     

热处理对电沉积Ni-W-P合金催化析氢性能的影响

 采用电沉积方法制备了Ni-W-P合金镀层,并在不同温度下进行热处理,通过极化曲线和交流阻抗谱研究了热处理温度对Ni-W-P合金催化析氢性能的影响. 结果表明,经200 ℃热处理的Ni-W-P合金电极析氢过电位最低,在电流密度为8.0 mA/cm2时,其析氢过电位较未经热处理的Ni-W-P合金电极减小约110 mV. 该样品的析氢电化学反应电阻为17.1 Ω·cm2, 交换电流密度约为未经热处理的Ni-W-P合金的5.0倍,析氢反应表观活化能降低. 差示扫描量热法、 X射线衍射和扫描电镜测试结果表明, Ni-W-P合金镀层经200 ℃热处理后发生低温结构弛豫,平均晶粒尺寸由1.1增大到2.8 nm, 合金由非晶结构转变为纳米晶结构,镀层表面形成宽度约为0.2 μm的微裂纹.     

纳米晶Ni-Mo-Co合金镀层的结构与析氢行为

电沉积;结构;纳米晶Ni-Mo-Co合金镀层的结构与析氢行为     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Synthesis and Optical and Redox Properties of Symmetric and Asymmetric BODIPYs

Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

钒与糖代谢及糖尿病

微量元素钒作为生物体内必需元素，经证实有很重要的生理学功能，与机体糖代谢有十分密切的关系，且能降低糖尿病动物模型的高血糖，极有可能被开发为治疗糖尿病的药物。     

Conformations and steric and stacking interactions of trisubstituted ureas and thioureas with alkyl and phenyl groups

The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R₂UPh type and -thioureas of the R₂TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments.     

Synthesis of Tyrosol and Hydroxytyrosol Glycofuranosides and Their Biochemical and Biological Activities in Cell-Free and Cellular Assays

Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection.     

Ferrocene and ferrocenium modified clays and their styrene and EVA composites

In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer.