纳米金/碳纳米管复合材料修饰电极催化鲁米诺电致发光体系的研究

制备了纳米金/多壁碳纳米管(MWNT)复合材料修饰电极,并将此电极应用于鲁米诺电化学发光体系.电化学发光实验表明,此复合材料修饰电极同时具备了纳米金和碳纳米管的催化性能.此外通过电极活性表面积测算、电化学交流阻抗实验等方法研究了纳米金和碳纳米管在此体系催化过程中的作用.纳米金/碳纳米管修饰电极具有良好的重现性,可以广泛应用于鲁米诺电化学发光测定体系.     

铂金纳米/壳聚糖/石墨烯修饰玻碳电极的制备及电化学性质研究

利用电沉积法制备了铂金纳米/壳聚糖/石墨烯修饰电极。利用扫描电镜(SEM)和能量色散X射线光谱(EXD)对铂金纳米/壳聚糖/石墨烯修饰电极进行了表征;采用循环伏安法(CV)对修饰电极电化学性质进行了研究,考察了电沉积时间和电位对修饰电极制备的影响,探讨了修饰电极对鸟嘌呤(G)的电催化作用。利用示差脉冲法(DPV)对G进行检测,在1.0×10~(-7)～1.4×10~(-6) mol·L~(-1)浓度范围内,G的氧化峰电流和浓度呈良好的线性关系,相关系数为0.9985,检出限(S/N=3)为6.1×10~(-8) mol·L~(-1)。该修饰电极可望用于实际样品中鸟嘌呤的测定。     

乙二醛在Ti/纳米TiO2-Pt修饰电极上的电催化氧化

采用溶胶.凝胶和电沉积法制备Ti基纳米TiO2-Pt(Ti/纳米TiO2-Pt)修饰电极.X射线衍射(XRD)表明纳米TiO2为锐钛矿型,扫描电镜(SEM)显示Pt纳米粒子在纳米TiO2多孔膜的表面呈现簇分散状态,平均粒径约25nm.通过循环伏安(CV)和计时电流法研究了Ti/纳米TiO2-Pt修饰电极对乙二醛直接电氧化的电催化活性,结果表明,修饰电极对乙二醛的直接电氧化呈现良好的催化活性,在0.60和1.23 V(vs SCE)出现两个氧化峰,二者电流密度分别为16和42 mA·cm2,约为纯Pt电极的2倍和1.5倍,反应过程受浓差扩散控制.     

离子液体-Ni微/纳米粒子协同电催化检测维生素B2

本文制备了离子液体-Ni微/纳米粒子修饰碳糊电极.研究了离子液体对Ni微/纳米粒子氧化还原的促进作用,用循环伏安法在0.1 mol/L B-R缓冲溶液(pH=4.5)中研究了维生素B2(VB2)在该修饰电极上的电化学行为,优化了各种实验条件.实验结果表明,本文制备的修饰电极能很好地催化氧化VB2,VB2在该修饰电极上的...     

氧化锌纳米簇-金纳米颗粒-壳聚糖复合膜修饰电极用于示差脉冲伏安法测定吗啡

将制备的氧化锌纳米簇和金纳米颗粒分散在壳聚糖中并滴涂在玻碳电极表面,制备了氧化锌纳米簇-金纳米颗粒-壳聚糖复合膜修饰电极(Au-ZnO-CHIT/GCE)。采用循环伏安法研究了吗啡在修饰电极上的电化学行为。结果表明:吗啡在该修饰电极上出现了一个氧化峰,提出了用示差脉冲伏安法测定吗啡的方法。吗啡浓度在5.3×10-6~6.5×10-4mol.L-1范围内与氧化峰电流呈线性关系,检出限(3S/N)为1.8×10-6mol.L-1。修饰电极用于尿液中吗啡的测定,回收率在80.0%~99.6%之间。     

乙二醛在Ti/纳米TiO2-Pt修饰电极上的电催化氧化

采用溶胶-凝胶和电沉积法制备Ti基纳米TiO2-Pt(Ti/纳米TiO2-Pt)修饰电极. X射线衍射(XRD)表明纳米TiO2为锐钛矿型, 扫描电镜(SEM)显示Pt纳米粒子在纳米TiO2多孔膜的表面呈现簇分散状态, 平均粒径约25 nm. 通过循环伏安(CV)和计时电流法研究了Ti/纳米TiO2-Pt修饰电极对乙二醛直接电氧化的电催化活性, 结果表明, 修饰电极对乙二醛的直接电氧化呈现良好的催化活性, 在0.60和1.23 V(vs SCE)出现两个氧化峰, 二者电流密度分别为16 和42 mA·cm-2, 约为纯Pt电极的2倍和1.5倍, 反应过程受浓差扩散控制.     

石墨烯/纳米金复合材料的无酶葡萄糖生物传感器制备

以抗坏血酸(AA)为还原剂,通过同步还原法制得石墨烯/纳米金复合材料.采用电化学方法,构建了一种基于石墨烯/纳米金复合材料修饰电极的无酶葡萄糖生物传感器.实验中,通过伏安法考察了不同修饰电极在葡萄糖溶液中的电化学行为.同时,探讨了溶液中OH-离子强度、溶解氧、扫描初始电位及石墨烯与纳米金的比例对传感器响应特性的影响.在...     

纳米氧化锌/镍修饰电极检测葡萄酒中甘油含量

本文制备了纳米氧化锌负载镍修饰电极,并将其应用于葡萄酒中甘油的检测。首先通过直接沉淀法合成氧化锌纳米粒子,并采用扫描电子显微镜和X-射线衍射仪对制备的氧化锌纳米粒子进行微观结构表征。然后,利用电化学合成法使镍纳米粒子均匀负载在氧化锌纳米粒子表面以制备具有甘油催化作用的修饰电极,采用循环伏安法研究了该修饰电极的电化学性能及最优操作条件。结果表明,反应溶液pH值为13.5时,该修饰电极性能最优,该修饰电极的反应过程为扩散控制过程;该修饰电极的线性检测范围为0.2 mM～60 mM,检测限为7.35×10~(-5) mol·L~(-1)(S/N=3),灵敏度为42.02 mA/(mol·cm~2)。另外,该修饰电极具有很强的抗干扰和样品检测能力,可应用于葡萄酒中甘油含量的快速检测。     

纳米金/三聚氰胺修饰电极检测亚硝酸盐

采用电聚合方法制备三聚氰胺(MA)膜修饰玻碳电极(GCE),然后采用原位恒电位沉积法制备金纳米颗粒(Au),并将其修饰于膜电极表面,制得纳米金/三聚氰胺修饰玻碳电极(Au/MA/GCE)。用扫描电子显微镜(SEM)对修饰电极进行表面形貌和元素成分分析。用循环伏安法研究亚硝酸根(NO2-)在该修饰电极上的电化学行为发现,NO2-在0.85 V出现一灵敏的氧化峰。在优化的实验条件下,NO2-在1.0×10-5～1.0×10-3mol/L浓度范围内与其氧化峰电流成线性关系,检测下限为8.9×10-7mol/L。将修饰电极用于实际样品中NO2-的检测,效果良好。     

纳米金/Nafion/石墨烯修饰玻碳电极检测对苯二酚的研究

采用一步电化学共还原的方法将纳米金(AuNPs)、Nafion、电化学还原石墨烯(ERGO)修饰到玻碳电极(GCE)表面,制成修饰电极AuNPs/Nafion/ERGO/GCE。以扫描电镜对其进行表征,用循环伏安法和微分脉冲伏安法研究对苯二酚在该修饰电极上的电催化行为。优化了实验参数,对苯二酚在2.0～100μmol/L及100～800μmol/L浓度范围内与其氧化峰电流呈良好的线性关系,检出限为0.3μmol/L。用该修饰电极成功地进行了实际水样中对苯二酚含量的测定。     

Synthesis of chlorobis/β-diketonato/oxotechnetium/V/ and tris/β-diketonato/technetium/III/ complexes

Chlorobis/-diketonato/ oxotechnetium/V/ complexes [TcOCl/-dik/₂, -diketone=acetylacetone, benzoylacetone and dibenzoylmethane] were newly synthesized using macroamount of⁹⁹Tc. These complexes were further separated into geometrical isomers. Furthermore, an improvement of the yields for the syntheses of tris/-dike-tonato/technetium/III/ complexes [Tc/-dik/₃, -diketone=acetylacetone, benzoylacetone and 2-thenoyltrifluoroacetone] was examined using Tc/III/-thiourea complexes as a starting material.     

Solvent extraction separation of In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/ with sulphoxides

Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.     

Separation of Tl/III/ from Tl/I/

A method for the separation of Tl/III/from Tl/I/ is reported employing 1-/2-pyridylazo/-2-naphthol /PAN/ and Rhodamine-B as extracting agents.     

An investigation of the promotional effect of propylene or propane traces on the activity of sulfatedPt/g-Al2O3andPt-Sn/g-Al2O3inCH4combustion

Summary A strong promoting effect of the presence of C₃H₈or C₃H₆was determined for the combustion of CH₄in excess oxygen, over pre-sulfated 1%Pt/g-Al₂O₃and pre-sulfated 1%Pt-2%Sn/g-Al₂O₃catalysts.</o:p>     

LixZryOz三元化合物的制备及表征

采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1～10μm间,BET分析表明样品比表面积处于1.0～9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.     

Analysis of nonvalent interactions in the crystals of conformational polymorphs of the composition CaHbNcOdSe by means of molecular voronoi-dirichlet polyhedra

Nonvalent interactions in crystals of compounds of the composition C _a H _b N _c O _d S _e that exhibit conformational polymorphism and have no fewer than four structurally characterized modifications are analyzed using molecular Voronoi-Dirichlet polyhedrals. A unique combination of the types of occurring intra- and intermolecular nonvalent contacts is shown to correspond to each conformational polymorph. Nonvalent interactions involving hydrogen atoms are found to occur most often in crystal structures, and least often those involving S, N, and O atoms.     

LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究

A series of single-phase Li_xNi_0.8-yCo_0.2Zn_yO_p(0.96 ≤x≤ 1.10， 0 ≤y≤ 0.05， 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method， in which LiOH·H₂O， Zn-doped spherical Ni(OH)₂ and Co₂O₃ were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD， SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine， narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity， but also a better cycling stability characterization than the un-doped one. The Li_1.06Ni_0.75Co_0.22Zn_0.03O_2.03 material has an initial reversible capacity as high as 160.5mAh·g^-1; and a first discharge efficiency 89.2%， and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.     

Crystal structure of Na3PO4 · 12H2O

The crystal structure of trisodium monophosphate hemihydrate was determined. The space group is $\text{C2}\text{c}$ and a unit cell contains eight formula units. The unit cell dimensions of $\text{Na}{}_3\text{PO}{}_4\text{·}\text{1}\text{2}\text{H}{}_2\text{O}$ are a = 9.631(3), b = 5.416(2), c = 16.938(8) Å, β = 102.60(5)°. The final R value is 0.027 for a set of 1430 independent reflections. This atomic arrangement is mainly a three-dimensional network of distorted NaO₆ octahedra. The hydrogen bonding scheme is given.     

橙红色荧光粉Ca_(1-x-y)Sm_xBi_ySiO_3的制备及其发光性能

以Sm3+作为激活剂,Bi3+作为辅助激活剂,采用水热法合成Ca1-x-ySmxBiySi O3前驱体,然后在1 100℃焙烧得到系列橙红色荧光粉。用X-射线衍射仪、扫描电镜和荧光分光光度计和傅里叶变换红外光谱等手段对样品的组成、结构和形貌及其发光性质进行分析和表征。分析结果表明:产物都为三斜晶系结构的Ca1-x-ySmxBiySi O3和四方结构的方石英Si O2共熔体。在405 nm近紫外光激发下,产物的发射光谱由3个峰组成,发射峰值位于566、606和650 nm处,分别归属于Sm3+的4G5/2→6HJ/2(J=5,7,9)跃迁。产物的激发光谱在405 nm有很强的发射带,与近紫外LED芯片匹配。随着Sm3+掺量的增加,样品发光强度先增强后减弱,当Sm3+的物质的量分数为3%时发光强度达到最大,浓度猝灭机理为电偶极-电偶极相互作用。当Bi3+的物质的量分数在0.3%~1.5%时,对产物Ca0.97Sm0.03Si O3的荧光强度起敏化作用。Sm3+和Bi3+的最佳物质的量分数分别为3%和0.5%。     

Isotope exchange behaviour of bis/diethyldithiocarbamate/mercury/II/ complex

Isotope exchange behaviour of bis/diethyldithiocarbamate/mercury/II/ complex has been studied at 25°C and 45°C varying the concentrations of both metal ion and the complex. The results show that the complex is kinetically labile. Temperature has a significant effect on the rate of the reaction. Increase in concentration increases the reaction rate.