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%.     

改进型溶胶-凝胶法制备粒径可调高染料吸附量TiO2微球及其在染敏电池光散射层中的应用

利用改进型的溶胶-凝胶法, 制得了由锐钛矿相纳米颗粒组成的TiO₂多孔微纳小球。通过调节前驱物浓度, 合成出粒径可控的尺寸分别为100, 175, 225, 475 nm的TiO₂微纳小球, 并通过电泳沉积法将合成出的小球作为光散射层引入到染料敏化太阳电池(DSSC)中。由于这种微纳小球在具备良好的光散射性能的同时也具备较高的染料吸附量, 因此相较于基于纳米颗粒的单层结构的DSSC拥有更高的光电转换效率。通过比较分析, 粒径尺寸为475 nm的微球作为光散射层的DSSC光电转换效率可以达到6.3%, 较之于基于纳米颗粒的DSSC提高了30%。     

In2O3敏化ZnO纳米棒阵列的性能及其光电催化活性

以掺氟SnO₂ (FTO)导电玻璃为基底, 采用水热法制备了ZnO纳米棒阵列. 通过In(NO₃)₃水溶液水洗的方法, 合成了In₂O₃敏化ZnO纳米棒阵列光催化剂. 采用场发射扫描电子显微镜(FESEM), X射线能谱(EDX), X射线衍射(XRD)及紫外-可见漫反射光谱(UV-Vis DRS)对样品的形貌、结构、组成、晶相等进行一系列的表征. 以罗丹明B (RhB)为目标降解物, 探究了In₂O₃敏化ZnO 纳米棒阵列光电催化活性. 采用场诱导表面光伏技术(FISPV)研究了不同含量的In₂O₃敏化ZnO纳米棒阵列在光照射下的光生电荷行为. 结合电化学工作站检测不同样品的光电流, 随着In₂O₃敏化量的改变, 光电流和开路电压也随之改变. 并探讨了In₂O₃敏化ZnO纳米棒阵列光生电荷行为与光电催化活性之间的关系. 结果表明, 适量In₂O₃敏化的ZnO光催化剂在可见光下2 h内对罗丹明B的降解效率达到95%, 是单纯ZnO纳米棒阵列的2.4倍.     

碳纳米管@SiO2@Ag纳米复合材料的制备及其表面增强拉曼效应

本文以SiO₂为中间层,在多壁碳纳米管(MWCNTs)表面负载Ag纳米粒子,制备出CNTs@SiO₂@Ag纳米复合材料,并采用TEM、XRD、UV-Vis、XPS等对纳米复合材料的结构、形貌和成分进行了表征,同时对该纳米复合材料的表面增强拉曼散射(Surface-enhancedRamanscattering,SERS)效应进行了研究。结果显示,Ag纳米颗粒有效提高了CNTs的SERS活性,纳米复合材料的拉曼峰强度是单纯CNTs拉曼峰强的近5倍。进一步研究了吸附罗丹明6G生物染料分子的SERS光谱,结果表明R6G分子的拉曼信号的质量与强度得到显著提高。因此,所制备的CNTs@SiO₂@Ag纳米复合材料有望作为SERS的活性基底,应用于生物无损检测领域。     

用于去除有机染料的分级结构ZnO微球的简便合成

以六亚甲基四胺(HMTA)为结构导向剂,采用乙二醇辅助的溶剂热法制备了均匀分散的纳米片组装的三维分级结构ZnO微米球。可控实验证明,HMTA和溶剂在分级结构微米球的形成中起重要作用。通过二维纳米片组装来构建三维分级结构,不仅增加了产品的比表面积,而且还建立了更多的电荷传输通道。在暗室下,该样品可作为吸附剂去除水溶液中的一些有机染料。吸附结果表明,纳米片组装的分级结构ZnO微球对阴离子染料具有良好的去除率和选择性。特殊的分级结构、较大的比表面积和静电引力的协同作用,使ZnO微球对代表性染料刚果红(CR)经过5次循环吸附后的去除率仍可达95.67%。动力学研究证实,CR在ZnO微球上的吸附为物理吸附,符合准二级动力学和Langmuir等温线模型。     

用于去除有机染料的分级结构ZnO微球的简便合成

以六亚甲基四胺(HMTA)为结构导向剂,采用乙二醇辅助的溶剂热法制备了均匀分散的纳米片组装的三维分级结构ZnO微米球。可控实验证明,HMTA和溶剂在分级结构微米球的形成中起重要作用。通过二维纳米片组装来构建三维分级结构,不仅增加了产品的比表面积,而且还建立了更多的电荷传输通道。在暗室下,该样品可作为吸附剂去除水溶液中的一些有机染料。吸附结果表明,纳米片组装的分级结构ZnO微球对阴离子染料具有良好的去除率和选择性。特殊的分级结构、较大的比表面积和静电引力的协同作用,使ZnO微球对代表性染料刚果红(CR)经过5次循环吸附后的去除率仍可达95.67%。动力学研究证实,CR在ZnO微球上的吸附为物理吸附,符合准二级动力学和Langmuir等温线模型。     

ZnO/BiOI微球的合成及其光催化性能

通过一步溶剂热法合成ZnO/BiOI纳米复合材料,在Bi（NO₃）₃·6H₂O、KI、ZnO和乙二醇（EG）溶剂中,制备出的样品尺寸和形貌采用X射线粉末衍射（XRD）、场发射扫描电镜（FESEM）、高分辨透射电镜（HRTEM）、紫外-可见漫反射光谱（DRS）、X射线光电子能谱（XPS）、N₂吸附-脱附等,对实验所得产物的组成、结构及光学性质等进行表征。以染料罗丹明B（RhB）水溶液和气态乙醛作为降解对象,采用BiOI、ZnO/BiOI和ZnO微纳材料作为光催化剂,通过对BiOI、ZnO/BiOI和ZnO微纳材料在可见光下光催化降解染料罗丹明B（RhB）水溶液和气态乙醛,结果表明多孔微纳材料的ZnO/BiOI具有更高的降解效率,实验表明多孔微纳材料的ZnO/BiOI具有更高的氧空位浓度,因此使其催化活性增强,讨论了其可能的催化活性机理。     

ZnO/BiOI微球的合成及其光催化性能

通过一步溶剂热法合成ZnO/BiOI纳米复合材料,在Bi（NO₃）₃·6H₂O、KI、ZnO和乙二醇（EG）溶剂中,制备出的样品尺寸和形貌采用X射线粉末衍射（XRD）、场发射扫描电镜（FESEM）、高分辨透射电镜（HRTEM）、紫外-可见漫反射光谱（DRS）、X射线光电子能谱（XPS）、N₂吸附-脱附等,对实验所得产物的组成、结构及光学性质等进行表征。以染料罗丹明B（RhB）水溶液和气态乙醛作为降解对象,采用BiOI、ZnO/BiOI和ZnO微纳材料作为光催化剂,通过对BiOI、ZnO/BiOI和ZnO微纳材料在可见光下光催化降解染料罗丹明B（RhB）水溶液和气态乙醛,结果表明多孔微纳材料的ZnO/BiOI具有更高的降解效率,实验表明多孔微纳材料的ZnO/BiOI具有更高的氧空位浓度,因此使其催化活性增强,讨论了其可能的催化活性机理。     

用于去除有机染料的分级结构ZnO微球的简便合成

以六亚甲基四胺(HMTA)为结构导向剂，采用乙二醇辅助的溶剂热法制备了均匀分散的纳米片组装的三维分级结构ZnO微米球。可控实验证明，HMTA和溶剂在分级结构微米球的形成中起重要作用。通过二维纳米片组装来构建三维分级结构，不仅增加了产品的比表面积，而且还建立了更多的电荷传输通道。在暗室下，该样品可作为吸附剂去除水溶液中的一些有机染料。吸附结果表明，纳米片组装的分级结构ZnO微球对阴离子染料具有良好的去除率和选择性。特殊的分级结构、较大的比表面积和静电引力的协同作用，使ZnO微球对代表性染料刚果红(CR)经过5次循环吸附后的去除率仍可达95.67%。动力学研究证实，CR在ZnO微球上的吸附为物理吸附，符合准二级动力学和Langmuir等温线模型。     

ZnO/RGO复合材料的结构及其光催化性能研究

本实验以ZnSO₄和氧化石墨(Graphite Oxide,GO)原料,在低温环境下(60 ℃)制备了层状ZnO/RGO(ZnO/Reduced Graphite Oxide)复合材料。通过对ZnO/RGO复合材料进行XRD、FTIR、XPS和FE-SEM等测试,表征了产物的晶相结构、界面状况及微观形貌特征。氧化石墨在与ZnO的复合反应过程中其活性基团消失或减弱,氧化石墨自身被还原为一种类石墨物质(Reduced GO,RGO);GO的预处理过程对产物的形貌有较大影响,采用稀碱溶液对石墨的剥离处理有利于产物的层状结构形成。本文还以甲基橙为目标降解物,考察了不同条件下所得催化剂的紫外光催化性能。研究表明,ZnO/RGO纳米复合材料大大提高了ZnO紫外光催化活性。光致发光谱(PL)显示,ZnO/RGO复合材料的荧光发射峰强度比纯ZnO有较大降低,说明ZnO的光激发电子在氧化石墨的还原产物RGO和ZnO纳米颗粒之间存在界面电子转移效应,因而抑制了ZnO中光生电子-空穴对的复合,从而提高了ZnO的光催化性能。     

Sol-Gel Synthesis of Hollow Zinc Ferrite Fibers

Hollow zinc ferrite fibers have been prepared via a facile citrate sol-gel process using Fe(OH)(HCOO)₂ prepared in laboratory and Zn(CH₃COO)₂⋅2H₂O as the original materials. The obtained hollow fibers were flexible and handlable with the outer diameter being 1–4 μm and the wall thickness less than 1 μm, and the fiber wall were made up of nanoparticles about 50 nm. Rheological behaviour of the precursor sol was tracked by Rheometer. The development of the gel fibers to zinc ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM and TEM.     

Syntheses,crystal structures,and some spectroscopic properties of zinc(II) complexes with N2O2 ligands derived from m-phenylenediamine and m-aminobenzylamine

The reaction of bis(salicylidene)-m-phenylenediamine with zinc(II) ion affords a 2?:?2 dinuclear zinc(II) complex formulated as [Zn₂(L¹)₂]. A similar 2?:?2 dinuclear zinc(II) complex, [Zn₂(L²)₂], can be obtained by reaction of bis(salicylidene)-m-aminobenzylamine with zinc(II) ion. These two dinuclear complexes slightly differ in their crystal structures, especially coordination environments around the zinc(II) centers, depending on the dissimilar flexibilities of the two ligands. The differences between the two complexes are reflected in their diffuse reflectance and photoluminescence behaviors.     

中空球状Fe3O4颗粒的合成及对刚果红溶液吸附-脱附能力的研究

通过简单的水热过程合成具有优良磁学性能的中空Fe3O4单晶颗粒。空心球状颗粒外部直径约500 nm,内径约200 nm,是由粒径为50 nm的颗粒团聚而成。随着反应时间的增加,相邻的Fe3O4纳米晶沿着(311)晶面取向团聚,经过奥斯瓦尔德熟化过程最终形成中空的球状颗粒。实验合成的Fe3O4粒子表现出特殊的磁学性能,具有相对较低的饱和磁化强度和较高的矫顽力。通过对刚果红溶液的吸附-脱附实验证明,中空结构Fe3O4颗粒对刚果红溶液有更高的吸附和脱附能力,在废水处理过程中,采用Fe3O4作为吸附剂,可以更高效的去除溶解的有机污染物,同时可以回收再利用,提高废水净化率,也进一步扩展了磁性材料的应用领域。     

溶剂热方法合成Cu2ZnSnS4空心球

以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu₂ZnSnS₄中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu₂ZnSnS₄中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu₂ZnSnS₄中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。     

Synthesis of Layered Hydroxide Zinc m‐Aminobenzoate Compounds and Their Exfoliation Reactions

Two types of layered hydroxide zinc m‐aminobenzoate compounds with structures of layered basic metal salt (LBMS) were prepared by the reaction of zinc hydroxide with m‐aminobenzoic acid solution in the temperature range of 40–120°C. The formation reactions, structures, chemical compositions, and exfoliation reactions of the layered compounds in alcohol solvents were investigated by XRD, TG‐DTA, SEM, and TEM. One layered phase with a basal spacing of 1.08 nm has a α‐Ni(OH)₂‐like structure, and its chemical formula can be written as Zn(OH)_0.67(m‐NH₂C₆H₄COO)_1.33. This phase has strip‐like particle morphology and cannot be exfoliated into its nanosheets in alcohol solvents. The other layered phase with a basal spacing of 2.66 nm has a zinc hydroxide‐nitrate‐like structure, and can be exfoliated in alcohol solvents.     

溶剂热方法合成Cu2ZnSnS4空心球

以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu₂ZnSnS₄中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu₂ZnSnS₄中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu₂ZnSnS₄中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。     

Supramolecular triads bearing porphyrin and fullerene via ‘two-point’ binding involving coordination and hydrogen bonding

Supramolecular triads composed of fullerene (C₆₀) as primary electron acceptor, zinc porphyrin (ZnP) as primary electron donor, and either a ferrocene (Fc), or N,N-dimethylaminophenyl (DMA), or N,N-diphenylaminophenyl (DPA) entity as a second electron donor were constructed via a ‘two-point’ binding motif involving axial coordination and hydrogen bonding. The B3LYP/3-21G(*) optimized structures revealed disposition of the three entities of the triads in a triangular fashion. The redox behavior of the different components was studied using cyclic voltammetry in o-dichlorobenzene containing 0.1 M (n-C₄H₉)₄NClO₄. The oxidation potentials of the second electron donor followed the trend: Fc<DMA<DPA, and the free-energy calculations suggested the possibility of the occurrence of sequential hole transfer in these triads. Efficient electron transfer from the excited singlet state of zinc porphyrin to the fullerene entity was observed in all of the studied triads in o-dichlorobenzene. Longer charge-separated states were observed for zinc porphyrin with a carboxylic acid compared with that having an amide group. The ratios of the experimentally determined forward to reverse electron transfer rates, k_CS/k_CR were evaluated to be 10³ for triads formed by zinc porphyrin with a carboxylic acid, suggesting charge stabilization in these triads.     

Rutile TiO2 Submicroboxes with Superior Lithium Storage Properties

Hollow structures of rutile TiO₂, and especially with non‐spherical shape, have rarely been reported. Herein, high‐quality rutile TiO₂ submicroboxes have been synthesized by a facile templating method using Fe₂O₃ submicrocubes as removable templates. Compared to other rutile TiO₂ nanomaterials, the as‐prepared rutile TiO₂ submicroboxes manifest superior lithium storage properties in terms of high specific capacity, long‐term cycling stability, and excellent rate capability.     

Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block†

Transformation of CO₂ into valuable organic compounds catalysed by cheap and biocompatible metal catalysts is one of important topics of current organic synthesis and catalysis. Herein, we report the zinc powder catalysed formylation and urealation of amines with CO₂ and (EtO)₃SiH under solvent free condition. Using 2 mol% zinc powder as the catalyst, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. When primary aromatic amines were used as the substrates, the reactions produce urea derivatives. The electronic and steric effects from the substrates on the formylation and urealation reactions were observed and discussed. The recovery and reusability of zinc powder were investigated, showing the zinc powder can be reused in the formylation reaction without loss of catalytic activity. The analysis on the reactants/products mixture after filtering out the zinc powder showed the zinc concentration in the mixture is low to 1 ppm. The pathways for the formylation and urealation of amines with this catalytic system were also investigated, and related to the different substrates.     

Dissolution of zinc oxide in a protic ionic liquid with the 1-methylimidazolium cation and electrodeposition of zinc from ZnO/ionic liquid and ZnO/ionic liquid–water mixtures

We show that zinc oxide can be dissolved in the protic ionic liquid 1-methylimidazolium trifluoromethylsulfonate, [MIm]TfO at quite a high concentration (~ 2.5 mol/L). FTIR and Raman spectra revealed the association of zinc ions with 1-methylimidazole. The ZnO/[MIm]TfO solutions and their mixtures with water were employed as electrolytes for the electrodeposition of zinc. High current density electrodeposition of zinc can be achieved in the employed electrolytes. Spongy-like zinc structures with a high porosity were obtained in ZnO/[MIm]TfO and the formation of Au_1.2Zn_8.8 alloy was observed. Compact and hexagonal zinc deposits were found in the presence of water. The present results show the potential of ionic liquids as electrolytes for rechargeable zinc–air batteries.