以聚丙烯酸钠为保护剂制备单分散纳米金粒子

以聚丙烯酸钠（PAAS）为保护剂,氯金酸溶液为前驱体,采用水合肼还原氯金酸的化学还原法成功地制备了单分散的纳米金粒子。利用X射线衍射（XRD）,紫外分光光度计（UV-vis）,透射电子显微镜（TEM）、红外光谱仪（FT-IR）和扫描电镜（SEM）等分析测试设备对样品进行了深入的研究与分析。讨论了反应条件对纳米金粒子粒径和形貌的影响。研究表明：所得到的纳米金粒径较小,分布较为均匀;氯金酸溶液用量、PAAS溶液用量和还原剂用量等对纳米金粒子的粒径影响较大。在本研究中,当PAAS溶液（0.1 g/L）用量为5 mL、氯金酸溶液（2 g/L）用量为1 mL、水合肼（85%）用量为4 mL时,所制备纳米金的粒径最小,平均粒径约为50 nm,均匀地分布在20～60 nm之间。     

离子膜电解法制备氯金酸及其机理探究

以Au为阳极、石墨为阴极、饱和甘汞电极(SCE)为参比电极、盐酸为电解质，采用离子膜电解法制备了氯金酸。探究了氯金酸制备过程中Au的阳极行为以及实验条件(Cl^–浓度、电解液pH、H₂O₂含量)对制备过程的影响，并对反应机理进行了探究。结果表明，实验所得样品化学式为HAu Cl₄·4H₂O，氯金酸产率可达94.57%;Au被电解为Au³⁺发生在阳极电位0.83～1.30 V(vs.SCE)之间，致钝电位为1.3 V(vs.SCE)；电解过程中减小电解液pH、增大电解液中Cl^–浓度可以促进Au的电解，峰电位随着pH的减小而降低；本实验条件下最佳电解条件为：电解电位1.25 V(vs.SCE)、电解液pH为1.0、Cl^–浓度1.0 mol/L、H₂O₂含量5 mmol。Nyquist图表明，氯金酸电解制备过程受电荷转移与扩散混合控制，随着溶液中Cl^–浓度...     

蔗糖水解制备金纳米粒子的研究

文章报道了一种工艺简单、条件温和、环境友好的绿色制备金纳米粒子的方法。以蔗糖为还原剂,在水解条件下还原氯金酸制备金纳米粒子。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)、能谱仪(EDX)对合成的金纳米粒子进行表征。实验系统的考察了水解时间、氯金酸添加量、反应时间等制备条件对纳米粒子光学性能的影响。实验结果表明最佳水解时间为20 min,金纳米粒子的粒径随着氯金酸溶液添加量及反应时间的增加而增大。     

埃洛石负载的纳米金可控制备及对环己烷选择性氧化的催化性能

埃洛石纳米管（HNTs）是一类具有独特物理结构和化学性质的天然黏土化合物,本文以经过提纯和聚二烯丙基二甲基氯化铵溶液（PDDA）改性的埃洛石为载体,将预先制备的粒径可控的金溶胶负载到改性埃洛石（PHNTs）表面得到负载型的纳米金颗粒,通过调节氯金酸前体的浓度和用量,实现了对负载型纳米金尺寸的有效调控,透射电镜表征结果显示,埃洛石负载的纳米金分散性良好,平均粒径分别处于2nm以下、2～5nm和5nm以上。以环己烷的液相选择性氧化为模型反应,评价了所制备的不同尺度负载型纳米金粒子的活性和对环己醇和环己酮的选择性。结果表明：纳米金颗粒的平均粒径处于2～5nm时,表现出最好的催化活性和选择性,在170℃和2.0MPa下反应2h,环己烷的转化率可达10.29%,环己醇和环己酮的选择性达85.75%,优于该反应体系使用的工业催化剂对活性和选择性的指标要求。此外,X射线光电子能谱仪表征结果显示,当埃洛石负载的纳米金平均粒径处于2～5nm时,金元素主要以Au⁰ 的形式存在。     

银纳米粒子的绿色合成及其光谱特性

以糊精为还原剂和稳定剂,采用微波高压液相绿色合成法制备了黄色银纳米粒子。用吸收光谱和共振散射光谱研究银纳米粒子的光谱特性。结果表明,在优化的最佳条件下,用该法制备的纳米银最大吸收峰在418 nm处,最强共振散射峰在486 nm处,银纳米粒子颗粒呈球形,粒度均匀,平均粒径为20 nm,单分散性较好。该法操作简单反应快速。     

微波合成(Au)_核·(Ag)_壳纳米粒子及其共振散射光谱研究

以柠檬酸化学还原法制备的金纳米粒子作晶种,采用微波高压液相合成技术,制备出分散性较好、规则球形的(Au)核·(Ag)壳复合纳米粒子。研究了(Au)核·(Ag)壳复合纳米粒子的紫外可见吸收光谱和共振散射光谱特性,在470nm处有最强共振散射峰,在404nm处产生一个吸收峰。结果表明,(Au)核·(Ag)壳复合纳米粒子的形成是导致470nm共振散射的根本原因。     

苝酰胺功能化磁性纳米材料的合成及其光/电性质

为了制备磁性荧光以及光电化学性能良好的多功能纳米粒子,采用微相乳液法,用二氧化硅(SiO_2)包裹Fe_3O_4磁性纳米粒子的同时,将苝酰胺与SiO_2表面的羟基反应,生成共价键连接的Fe_3O_4@SiO_2-(1a)和Fe_3O_4@SiO_2-(2a)纳米粒子,用红外光谱、XRD、SEM、UV-Vis吸收光谱、荧光光谱及ECL进行表征。结果表明,与化合物1a、2a相比,复合物Fe_3O_4@SiO_2-(1a/2a)的电子吸收和荧光光谱峰型相同,峰位置略有移动。在一定浓度范围内,Fe_3O_4@SiO_2-(2a)纳米粒子的ECL强度随浓度增大而降低,且其在50¹00 s的区间内基本稳定。     

环丙沙星苯乙基衍生物钴配合物的合成研究

近年来，随着喹诺酮药物在临床中使用量的增大，细菌对其产生了抗药性，因此研发新一代的高效率的环丙沙星的越来越重要。根据构效关系，将苯乙基引入到环丙沙星7位哌嗪环N-4位上,以期获得抗菌谱更广、抑菌性能更好的环丙沙星衍生物。然后合成金属配合物，使其具有新的生理活性。研究了温度、时间、物料比3个单因素对衍生物产率的影响，通过响应面法得到最佳工艺条件。实验结果表明，环丙沙星苯乙基衍生物在反应时间8.94 h，反应温度100.625℃，反应物料摩尔比为1∶1.1下，产率最高为38.206 3%。测得衍生物的熔点为270～275℃、红外光谱在3 500～3 300cm^-1处没有N-H的吸收峰，在1 500～670 cm^-1处出现C-N的吸收峰，并在3 396、1 454、1 496 cm^-1处出现了新的吸收峰，核磁共振氢谱在7.3、2.7、1.2 ppm处出现了新的吸收峰。同时合成了其金属配合物，并用紫外、红外光谱表征了其结构。红外光谱在1 725 cm^-1和1 628 cm^-1没有峰出现...     

运用静电纺丝技术制备金/壳聚糖/PVP复合纳米纤维

在加热条件下,以乙酸作为溶剂,用壳聚糖还原氯金酸制备了金纳米粒子。壳聚糖分子还保护了生成的金纳米颗粒,因此壳聚糖既为还原剂又是保护剂。紫外吸收光谱证实了溶液内金纳米粒子的存在。采用静电纺丝技术制备了含有金纳米粒子的壳聚糖/聚乙烯吡咯烷酮(PVP)复合纳米纤维。运用透射电镜(TEM)对纤维的表面形貌及纤维内的金纳米粒子的分布进行了表征。     

基于多巴胺共振散射光谱法测定牛奶中的三聚氰胺

在氢氧化钠介质中,氯金酸与多巴胺发生氧化还原反应生成金纳米粒子而使体系在519. 4 nm处产生一个较强的共振散射峰。当加入三聚氰胺时,多巴胺和三聚氰胺通过氢键结合并形成稳定的多氢键化合物,使得结合的多巴胺还原能力降低而不能还原氯金酸,阻碍金纳米粒子的形成,导致体系519. 4 nm处的共振散射峰强度降低。据此建立了检测三聚氰胺的共振散射光谱法。在优化的实验条件下,c(三聚氰胺)在8. 33×10-7~1. 67×10-5mol/L范围内与该共振散射峰强度的降低值(ΔI519. 4 nm)呈良好线性关系,其相关系数为0. 996 1,检出限为2. 1×10-7mol/L。将该共振散射光谱法用于牛奶制品中的三聚氰胺的测定,回收率为96. 0%~108. 0%,相对标准偏差为1. 3%~2. 7%。     

Preparation of vapreotide-templated silver nanocages and their photothermal therapy efficacy

Vapreotide acetate(Vap) was used as a biotemplate to synthesize silver nanocages through direct co-incubation of a AgNO_3 solution, following by reduction using fresh NaBH_4. The characterized vapreotide-templated silver nanocages(Vap-Ag ) presented a wide and red shifted absorption band with a maximum between 480 nm and 800 nm and possessed a uniform structure with a face-centered cubic crystal structure. The biocompatibility of Vap-AgN Cs was assessed using the MTT method, indicating Vap-AgN Cs had better biocompatibility when its concentration was lower than 2.5 × 10~(-4) mmol·L~(-1). The photothermal characteristics of Vap-Ag NCs were analyzed with laser irradiation(808 nm, 1.5 W·cm~(-2)) and the results showed that the temperature of the VapAg NCs solution reached 45 °C starting from 25 °C within 5 min. Additionally, Vap-Ag NCs with a laser led to HeL a cell death. Therefore, the prepared Vap-AgN Cs is expected to be an effective photothermal therapy agent.     

超声波强化制备高取代度大米淀粉乙酸酯

高取代度乙酸酯(DS>2)由于其热塑性及疏水性, 在高分子领域应用广泛。以大米淀粉为原料, 对甲苯磺酸为催化剂, 在冰乙酸/乙酸酐体系中, 采用了超声强化方法制备高取代度乙酸酯淀粉, 并用FTIR、XRD 和SEM对产物进行表征。考察了超声作用时间、超声温度、超声功率对大米淀粉乙酸酯取代度(DS)的影响, 并用响应面法对超声条件进行了优化, 得到的最佳工艺如下:超声时间为15.67min, 超声温度为31.33℃, 超声功率为85.60W, 在此条件下, 得到的乙酸酯淀粉的取代度为2.77。由FTIR图谱可知, 乙酸酯淀粉在1750cm^-1、1433cm^-1、1375cm^-1及1239cm^-1处出现了乙酰基的特征峰, 证明成功地制得了高取代度乙酸酯淀粉。XRD和SEM结果表明, 乙酰化后淀粉的结构完全被破坏。研究结果为高取代度淀粉乙酸酯的工业生产提供了依据。     

氨缓冲体系强化高纯重质碳酸锰的制备

以碳酸钠和高纯硫酸锰为原料,通过共沉淀法在氨缓冲溶液中制备高纯重质碳酸锰。当硫酸锰和碳酸钠溶液浓度都为1.5 mol·L^-1、碳酸钠过量系数为110%、溶液pH为8.5、温度为50℃、滴加速率为120 ml·h^-1时,得到的碳酸锰视密度达1.67 g·cm^-3,振实密度达2.15 g·cm^-3。氨缓冲体系增加了溶液的稳定性,抑制了溶液中氢氧化锰和偏氢氧化锰的生成,制备出的高密度碳酸锰形貌趋于球形,粒径分布均匀,D₅₀平均大小为30.32 μm。以本研究制备的碳酸锰为锰原料焙烧得到的四氧化三锰松装密度为1.09 g·cm^-3,振实密度为2.18 g·cm^-3,锰的含量可达71.85%。     

铁铝柱撑酸化蒙脱土催化剂的表征及催化性能

为改善柱撑蒙脱土的催化活性,对蒙脱土进行酸预处理,并采用离子交换法制备铁铝柱撑酸化蒙脱土(Fe-Al-酸化土)催化剂,通过XRD、BET、ICP和FI-IR对其进行表征。结果表明,蒙脱土经酸化预处理制备Fe-Al酸化土催化剂比表面积为157.3 m~2·g~(-1),层间距d001为1.787 nm,铁铝柱撑剂进入酸化蒙脱土层间域形成均一稳定的Si—O—Fe结构,在2 930 cm-1处出现尖锐的吸收峰,在协同过氧化氢降解废水实验中表现出较高的活性和稳定性。     

Raman study of SrBi2Ta2O9 thin films

Thin films of SrBi₂Ta₂O₉ (SBT) were deposited on Si using Sol-Gel technique. The thicknesses of the films 200 nm (SBT2) and 400 nm (SBT4), respectively. SEM were studies showed most of the grains in the film are smaller than 0.1 μ. FTIR reflectivity measurements of the samples showed bands around 1260, 936(for SBT2), 955(for SBT4), 770, 600 cm^-1. Micro Raman spectra shows bands corresponding to the SBT materials, but some frequency shifts and broadening were observed. Particularly, the band around 818 cm^-1, which corresponds to a stretching of the TaO₆ octahedron, was found to change from 785 to 827 cm^-1. This change seems to be related to the Ta-O bond length.     

Electronic absorption spectrum of Co2 ions doped in lithium caesium sulphate single crystal

Single crystals of Lithium Caesium Sulphate doped with Co²⁺ ions were grown by slow evaporation of an aqueous solution of Lithium Sulphate and Caesium Sulphate to which Cobalt Sulphate is added as dopant. Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary-17 Spectrophotometer. When the crystal is cooled to liquid nitrogen temperature changes in intensity and band position are observed and some of the bands are splitted. From the nature and position of the bands a successful interpretation of all the observed bands have been made and identified as those belonging to Co²⁺ ion in an octahedral crystal field. The crystal field parameters derived for room temperature are Dq = 870 cm^-1, B = 900 cm^-1 and C = 3150 cm^-1 and for liquid nitrogen temperature are Dq = 880 cm^-1, B = 900 cm^-1, C = 3150 cm^-1 and ζ = 500 cm^-1.     

Preparation of Au/TiO2 catalysts from Au(I)–thiosulfate complex and study of their photocatalytic activity for the degradation of methyl orange

Gold loaded on TiO₂ (Au/TiO₂) catalysts were prepared using Au(I)–thiosulfate complex (Au(S₂O₃)₂³⁻) as the gold precursor for the first time. The samples were characterized by UV–vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), and X-ray photoelectron spectroscopy (XPS) methods. Using Au(S₂O₃)₂³⁻ as gold precursor, ultra-fine gold nanoparticles with a highly disperse state can be successfully formed on the surface of TiO₂. The diameter of Au nanoparticles increases from 1.8 to 3.0 nm with increasing the nominal Au loading from 1% to 8%. The photocatalytic activity of Au/TiO₂ catalysts was evaluated from the analysis of the photodegradation of methyl orange (MO). With the similar Au loading, the catalysts prepared with Au(S₂O₃)₂³⁻ precursor exhibit higher photocatalytic activity for methyl orange degradation when compared with the Au/TiO₂ catalysts prepared with the methods of deposition–precipitation (DP) and impregnation (IMP). The preparation method has decisive influences on the morphology, size and number of Au nanoparticles loaded on the surface of TiO₂ and further affects the photocatalytic activity of the obtained catalysts.     

细菌纤维素负载金纳米粒子复合膜的制备及催化性能

以细菌纤维素(BC)为基底,氯金酸(HAu Cl4)为金前驱体,通过原位还原法制备了BC负载金纳米粒子(Au NPs)复合膜。采用紫外-可见光谱仪、透射电子显微镜、X射线衍射仪、电感耦合等离子发射光谱仪和傅里叶变换红外光谱仪对复合膜的结构和性质进行了表征,并通过对硝基苯酚(4-NP)催化还原反应来评价Au NPs-BC复合催化剂的催化性能。研究结果表明:复合膜上Au NPs的粒径大小为(5.30±1.23)nm,其反应速率常数高达5.09×10-3s-1,Au NPs-BC催化剂表现出优异的催化活性及重复稳定性。     

Electronic absorption spectrum of Co2 ions doped in potassium dihydrogen phosphate single crystal

Single crystals of Potassium dihydrogen phosphate doped with Co²⁺ ions were grown by slow evaporation at room temperature from a saturated solution of Potassium dihydrogen phosphate to which 0.5 mole percent of Cobalt phosphate was added as an impurity, Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary - 2390 Spectrophotometer. When the crystal is cooled to liquid nitrogen temperature, changes in intensity and band position are observed and some of the bands are splitted. From the nature and position of the bands, a successful interpretation of all the observed bands have been made and identified as those belonging to Co²⁺ ion in an octahedral crystal field. The crystal field parameters derived for room temperature are Dq = 860 cm^-1, B = 920 cm^-l and C = 3680 cm^-1 and for liquid nitrogen temperature are Dq = 870 ^cm-l, B = 920 cm^-1, C = 3680 cm^-l and S = 500 cm^-1.