纳米ZnO的固相合成及其对锌电极的改性作用

利用固相配位化学反应制备了纳米ZnO粉体 ,借助XRD、TEM进行了表征 ,并采用循环伏安法和循环充放电法对电化学性能进行了分析。循环伏安测试表明 ,在较慢扫速 (1mV s)下 ,不同组成电极的峰形相差较大 ,添加 5 0 %纳米ZnO的混配电极展示出良好的循环可逆性。恒流充放电测试结果表明 ,添加 5 0 %的ZnO对锌电极具有较好的改性作用 ,提高了锌电极的循环充放电性能 ,但纳米ZnO对锌电极的改性效果明显优于普通粒径ZnO。在循环充放电第 2 5周和 3 0周时放电容量分别为 2 2 0mA·h g和 1 98mA·h g。     

纳米结构ZnO/染料/聚吡咯光阳极的光电化学性质

用光电化学方法研究了染料RuL2 (NCS) 2 (L =2 ,2′ bipydine 4,4′ dicarboxylicacid) (简写为Dye)、聚吡咯 (PPy)敏化氧化锌 (ZnO)纳米晶电极以及用RuL2 (NCS) 2 和PPy复合敏化ZnO纳米晶膜电极的光电化学行为 .实验表明 ,ZnO/PPy纳米多孔膜电极为双层n 型半导体结构 .PPy和RuL2(NCS) 2 都可对ZnO纳米晶膜产生敏化作用 ,ZnO/RuL2 (NCS) 2 /PPy复合多孔膜电极产生的光电流远大于ZnO/PPy纳米多孔膜电极和ZnO/Dye多孔膜电极产生的光电流 .讨论了该电极的光生电子的机理 ,初步测定了ZnO/RuL2 (NCS) 2 /PPy电极作为光阳极的光电化学电池的工作特性曲线 ,测得该电池的光电转换效率为 1 .3% ,填充因子为 0 .75 .     

硫化氧化两步法提高(110)取向ZnO纳米片比表面及其光电极应用

以硫代乙酰胺为硫源, 通过一种较温和的溶剂热法先将生长于氟掺杂的SnO₂ (FTO)导电玻璃上的ZnO纳米片硫化, 再将其在空气中高温焙烧氧化,利用ZnO/ZnS晶格的膨胀收缩效应使ZnO纳米片表面粗糙化,达到提高其比表面积的目的. 系统研究了该硫化氧化两步法中ZnO纳米片、硫化后的ZnS纳米片、硫化氧化后的ZnO纳米片薄膜的形貌、物相、比表面积及孔径分布的变化. 并将硫化氧化前后两种ZnO纳米片阵列薄膜制成染料敏化太阳电池的光电极, 分别对电池的电流密度-电压(J-V)特性进行了表征. 实验结果表明, 经过硫化氧化后的ZnO纳米片的比表面积大约是未经该处理的ZnO纳米片的2倍, 同时前者的太阳电池光电转换效率(IPCE)相对于后者提高33%.     

电沉积制备ZnO纳米棒修饰电极上氧化还原蛋白的电化学行为

采用恒电位阴极还原法在金电极表面一步修饰ZnO纳米棒, 制备成ZnO纳米棒修饰电极. 扫描电子显微镜(SEM)和X射线衍射(XRD)结果显示制得的ZnO为直径约100 nm的六棱柱状纤锌矿晶体纳米棒. 使用ZnO纳米棒修饰的金电极研究细胞色素c的直接电化学行为, 结果表明: ZnO纳米棒修饰的金电极能有效探测到细胞色素c的铁卟啉辅基在不同价态下的电化学行为; 细胞色素c吸附后, ZnO纳米棒修饰的金电极对过氧化氢的电流响应呈现良好的线性关系.     

图案化锥形氧化锌纳米带的原位热氧化法制备与发光性质

采用光刻技术制备出图案的锌膜,所得锌膜与纯氧在700℃氧化反应10 min,在锌膜的表面上原位生长出具有图案的锥形ZnO纳米带阵列,实现了ZnO纳米带生长位置的可控生长。锌膜上得到的锥形ZnO纳米带为单晶六方纤锌矿结构,长度在1～4μm,纳米带根部和顶部的宽度分别在300～700 nm和100～300 nm。提出了锥形ZnO纳米带的可能生长机理。在波长为300nm光的激发下,发现了锌膜上锥形ZnO纳米带具有发光峰位于395 nm弱的紫外光发光和510 nm强的蓝绿光发光,它们分别起源于ZnO宽带隙的激子发射以及表面上离子化氧空位中的电子与价带中光激发的空穴之间的复合。     

具有核壳结构的ZnO纳米棒@Ni-Co双氢氧化物复合物纳米片阵列的制备及其电化学性能

通过两步水热合成法制备了具有核壳结构的ZnO纳米棒@Ni-Co双氢氧化物复合材料纳米片阵列.首先,以碳布为基底,水热法生成的ZnO沉积在碳布上形成ZnO纳米棒花簇.其次,以ZnO纳米棒为模板,水热法生成的Ni-Co双氢氧化物纳米片沉积在ZnO纳米棒表面,形成ZnO纳米棒@Ni-Co双氢氧化物纳米片复合材料阵列.形貌、结构分析和电化学性能测试表明,以碳布为基底,成功地合成了以ZnO纳米棒为模板并具有核壳结构的ZnO纳米棒@Ni-Co双氢氧化物复合材料纳米片阵列,该复合材料纳米片阵列具有较大的纵横比,且分散均匀.合成的ZnO纳米棒@Ni-Co双氢氧化物复合材料纳米片阵列具有良好的电化学性能,当电流密度为1 A/g时,其比电容值可达531.6 F/g,该复合材料在超级电容器电极材料领域具有良好的应用前景.     

水热法生长方式对ZnO纳米棒阵列结构和性能的影响

本文系统地比较了三种方式制备的ZnO纳米棒阵列的结构和性能的异同.根据水热法生长液中碱来源的不同,ZnO纳米棒阵列的生长方式分为三种:N方式(氨水)、H方式(六次甲基四胺)和NH方式(两次N方式和一次H方式).通过扫描电子显微镜,对这三种方式生长的ZnO纳米棒阵列形貌进行了表征.此外,利用X射线衍射仪、透射电子显微镜和激光拉曼光谱对ZnO的结晶性能进行比较.结果表明,ZnO纳米棒阵列的取向性N≈NH>H,ZnO的晶体质量H>NH>N.NH方式综合N方式和H方式的优势,得到了取向性和晶体质量优良的ZnO纳米棒阵列.这将为在进一步应用中有效地选择ZnO纳米棒阵列的制备方式提供重要信息.     

CdS量子点敏化ZnO纳米棒阵列电极的制备和光电化学性能

采用连续式离子层吸附与反应法制备了CdS量子点敏化的ZnO纳米棒电极.应用扫描电子显微镜(SEM)、X射线衍射(XRD)和透射电子显微镜(TEM)对CdS量子点/ZnO纳米棒电极的形貌、晶型和颗粒尺寸进行了分析和表征;采用光电流-电位曲线和光电流谱研究了不同CdS循环沉积次数及不同沉积浓度对复合电极的光电性能影响.结果表明,前驱体浓度都为0.1mol·L-1且沉积15次敏化后的ZnO纳米棒阵列电极光电性能最好.与单纯的ZnO纳米棒阵列电极和单纯的CdS量子点电极相比,其光电转换效率显著提高,单色光光子-电流转换效率(IPCE)在380nm处达到76%.这是因为CdS量子点可以拓宽光的吸收到可见光区,并且在所形成的界面上光生载流子更容易分离.荧光光谱实验进一步说明了光电增强的原因是,两者间形成的界面中表面态大大减少,有利于减少光生电子和空穴的复合.     

微波法合成氧化锌纳米棒

以氯化锌为锌源,碳酸钠为矿化剂,水为溶剂,微波辐照10 min制备了结晶性好的半导体ZnO纳米棒.经XRD,FESEM,TEM和SAED表征,ZnO纳米棒直径为40 nm～80 nm,长度为300 nm～500 nm,沿着c轴择优取向生长.对ZnO纳米棒生长机制进行了分析.     

聚乙烯醇辅助合成ZnO纳米带及其表征

本文中以乙酸锌[Zn(CH3COO)2·2H2O]和高分子聚乙烯醇(PVA)为原料, 通过控制升温速度、调节溶液浓度, 于550 ℃合成了不同形貌和尺寸的ZnO纳米带.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.