Ag2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物，在甲苯一水两相界面处合成了Ag2S纳米粒子。采用紫外一可见吸收光谱（U弘Vis）、透射电子显微镜（TEM）和广角X射线衍射（WAXD）等方法对Ag2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明，通过改变甲苯一水两相界面反应体系的条件，可以得到粒子尺寸窄分布的Ag2...     

蔗糖酯对纳米氧化银的稳定性及抗菌性影响研究

针对纳米氧化银(Ag_2O)制备过程中,纳米Ag_2O粒子易团聚,导致其抗菌性降低的问题,以蔗糖酯(SE)作为表面活性剂,考察不同蔗糖酯添加量对纳米Ag_2O稳定性和抗菌性的影响。结果表明,在化学沉淀法制备纳米Ag_2O的条件下添加适量的蔗糖酯,纳米Ag_2O的稳定性和抗菌性能均得到提高。     

纳米棒状Ag3PO4/TiO2异质结复合材料的可见光催化性能

采用水热法制备了一维棒状TiO_2纳米材料,再通过原位生长法合成了棒状纳米Ag_3PO_4/TiO_2复合材料,制备了不同摩尔量的纳米棒状Ag_3PO_4/TiO_2异质结复合材料。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱仪(XPS)、漫反射紫外-可见近红外光谱仪(UV-Vis-DRS)和电化学阻抗谱(EIS)对纳米棒状Ag_3PO_4/TiO_2异质结复合材料的晶体结构、形貌、光吸收特性和电子复合情况等进行了表征,并在可见光照射下研究了甲基橙和苯酚的光降解率。结果表明:制备的纳米棒状TiO_2具有更大的比表面积,为纳米Ag_3PO_4的负载提供更多的活性位点,提高了光利用效率;Ag_3PO_4/TiO_2复合材料有异质结的形成,其内建电场可有效提高电子-空穴对的分离效率,进而提高材料的光催化性能和稳定性。     

水热法合成Ag_2S/Bi_2S_3复合材料及其热电性能研究

采用水热合成法结合放电等离子烧结技术制备了Ag_2S/Bi_2S_3块体热电复合材料。采用XRD、SEM和TEM对合成粉末材料的相组成和微观形貌进行分析,闪光法和塞贝克系数/电阻测量系统测试复合块材的热电性能,系统地研究了Ag_2S的含量对Ag_2S/Bi_2S_3复合材料热电性能的影响。实验结果表明,水热法成功地合成了具有球形结构的Ag_2S/Bi_2S_3复合粉末;块体样品的塞贝克系数都为负,说明样品为n型半导体;适量的Ag_2S复合Bi_2S_3不仅有效地降低了材料的热导率,同时也提高了电导率;当Bi_2S_3与3%的Ag_2S复合时样品的热电优值(ZT值)最大,其在724K时的ZT值为0.23,为纯Bi_2S_3样品在该温度ZT值的2.3倍。     

L-半胱氨酸辅助反相微乳法制备Ag_2S纳米晶

选用TX-100/环己烷/正己醇/水反相微乳体系,以Ag NO_3为Ag源、Na_2S·9H2O为S源、L-半胱氨酸为结构导向剂,室温下制备了高晶化度、直径为10—50 nm的Ag_2S纳米晶,并考察了影响其粒径大小的因素。紫外-可见吸收光谱表明,Ag_2S纳米晶在290 nm处呈现强吸收,与体相Ag2S(1 240 nm)相比,其吸收边发生了明显的蓝移。通过调控微乳体系中ω0(水与表面活性剂物质的量比)、Ag+与L-半胱氨酸的物质的量比、反应物浓度等可以实现对产物尺寸和形貌的调控。     

Ag_2CO_3/Ag/g-C_3N_4 Z-型异质结的制备及可见光催化降解RhB

通过煅烧处理和沉淀反应合成以Ag纳米粒子为电子媒介的Z-型光催化剂Ag_2CO_3/Ag/g-C_3N_4。在可见光照射下,降解RhB评价Ag_2CO_3/Ag/g-C_3N_4复合物的光催化活性。结果表明:Ag2CO3/Ag/g-C3N4样品显示出比纯Ag_2CO_3和g-C_3N_4更强的光催化活性,当g-C3N4与Ag_2CO_3/Ag质量比为20%时,复合物呈现出最好的光催化性能,这归因于在Ag_2CO_3和g-C_3N_4间形成的Z-型异质结构,其有效促进电子转移速率和光生电子-空穴的分离。Z-型异质结构扩展了可见光吸收波长范围(从450nm到670nm),这是由于Ag纳米粒子表面离子共振的结果。捕获实验证实,在光催化降解RhB反应中,·O_2~-和空穴h~+是主要活性物质,·OH是次要活性物质,并提出了增强光催化活性的机理。     

修饰纳米CdS/聚合物的界面相互作用与光学性能

采用微乳液法结合原位表面修饰合成了纳米尺度的硫化镉粒子,采用溶液共混和静态铺膜方法制备了纳米粒子/聚合物复合体系,以研究纳米粒子与聚合物间的界面作用.结果表明,经修饰的纳米CdS粒子比较均匀地分散于聚合物基体内,纳米粒子与聚合物基体间存在较强的相互作用.根据复合体系的紫外-可见吸收光谱和荧光光谱,分析了表面修饰(表面修饰剂种类、表面修饰剂用量等)对纳米粒子的分散以及复合体系界面特性的影响,证实了表面修饰剂具有促进纳米粒子分散和消除粒子表面缺陷的作用.     

氨基修饰磁性氧化铁纳米粒子的制备

以聚乙二醇(PEG)为溶剂,高温热分解乙酰丙酮铁(Fe(acac)3)合成了磁性氧化铁纳米粒子。为改善氧化铁纳米粒子表面性能和生物应用潜能,分别用N,N二甲基甲酰胺和聚酰胺-胺(PAMAM)进行表面修饰,在氧化铁纳米粒子表面接枝-NH2活性官能团。分别采用X射线衍射仪(XRD)、透射电镜(TEM)、红外光谱(FT-IR)、动态光散射(DSL)对样品进行了表征测试。XRD和TEM结果表明高温热分解法合成的纳米粒子平均粒径为10nm,具有较好的结晶性和单分散性;FT-IR、DSL粒径和表面电位测试结果表明氨基官能团成功修饰在氧化铁纳米粒子表面,同时使氧化铁纳米粒子在水溶液中的稳定性增强。     

巯基表面修饰磁性复合纳米粒子用于重金属离子去除的研究

采用化学共沉淀法合成磁性Fe3O4纳米粒子,并且利用正硅酸乙酯(TEOS)的水解和凝聚作用在Fe3O4纳米粒子表面沉积包覆一层SiO2,合成核壳式的Fe3O4@SiO2复合纳米粒子。以Fe3O4@SiO2纳米粒子为基体,将(3-巯基丙基)三乙氧基硅烷嫁接到纳米粒子表面,制备出巯基功能化的纳米材料,将其应用于对重金属离子的吸附。由于功能化纳米粒子具有超顺磁性,为纳米粒子吸附重金属粒子后的分离提供了便利。通过TEM、XRD、FTIR、VSM等手段对Fe3O4@SiO2复合纳米粒子进行表征。     

Ag3PO4/Au/TiO2纳米片异质结薄膜的制备及其光催化性能研究

以钛片(Ti)、氯金酸(HAuCl_4)和硝酸银(AgNO_3)为主要原料,采用碱热法、微波辅助化学还原法和浸渍-沉积法三步法制备了磷酸银(Ag_3PO_4)/金(Au)/二氧化钛纳米片(TiO_2NSF)异质结薄膜(Ag_3PO_4/Au/TiO_2NSF)光催化剂,并对其进行了表征,探究了其在模拟太阳光条件下降解水相中有机染料亚甲基蓝(MB)和清除气相中氮氧化物(NO_x)的性能。结果表明,在模拟太阳光光照140min条件下,Ag_3PO_4/1.0Au/TiO_2NSF对MB的去除率达到99.9%;在模拟太阳光照射条件下,Ag_3PO_4/1.0Au/TiO_2NSF对NO的光催化转化率达到98.2%。采用捕获剂确定空穴(h~+)是主要的活性物种,超氧自由基(·O_2~-)是次要活性物种。Z机制和Au纳米粒子的局域表面等离子体共振效应的协同作用是复合光催化剂催化性能增强的主要原因。     

牛血清白蛋白辅助合成Ag2Se-Se复合纳米粒子

本文利用牛血清白蛋白(BSA)作为表面活性剂,在水相中成功合成了具有复合结构的Ag2Se-Se纳米粒子。该复合纳米粒子具有较好的分散性。整个实验过程均在室温下进行,合成方法简单、可控且重复性好。结合傅立叶变换红外光谱(FTIR)和紫外吸收光谱(UV-vis)的结果,分析了纳米粒子复合结构的形成过程;采用高分辨透射电子显微镜(HRTEM)结合选区电子衍射(SAED)和能谱分析(EDS),对制备的复合粒子形貌和成份组成进行了分析测定;利用X射线粉末衍射(XRD)分析了复合粒子的晶体结构和相组成。采用BSA修饰制备得到的纳米粒子生物相容性好,可以在生物医学领域中得到广泛应用。     

银、铜硫化物纳米球的活性模板合成及其光学性能研究

首次利用胶棉人工活性膜模板．在隔膜组装体系中．一步高效地合成了具有良好光学性能且形貌较规则的Ag2S、CuS纳米球,所得产物分别为单斜多晶结构和六方多晶结构,平均粒径分别为28、20nm。两种纳米球均保留了半导体材料的红外透过性能和荧光发光性能．紫外一可见光谱中有新的吸收峰出现．不同于体相材料,表现出明显的量子尺寸效应。     

One-dimensional Ag2S/ZnS/ZnO nanorod array films for photocathodic protection for 304 stainless steel

Highly ordered Ag_2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag_2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag_2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt% NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.     

Electrical properties of a novel 1,3-bis-(p-iminobenzoic acid) indane Langmuir-Blodgett films containing ZnS nanoparticles

ZnS nanoparticles have been formed in a newly synthesized 1,3-bis-(p-iminobenzoic acid) indane (IBI) by exposing Zn2+ doped multilayered Langmuir-Blodgett (LB) film to H2S gas after the growth. The formation of ZnS nanoparticles in the LB film structure was verified by measuring UV-Visible absorption spectra. DC electrical measurements were carried out for thin films of IBI prepared in a metal/LB films/metal sandwich structure with and without ZnS nanoparticles. It was observed that ZnS nanoparticles in the LB films cause a blue-shift in the absorption spectra as well as a decrease in both capacitance and conductivity values. By analysing I-V curves and assuming a Schottky conduction mechanism the barrier height was found to be about 1.13 eV and 1.21 eV for IBI LB films without and with ZnS nanoparticles, respectively. It is thought that the presence of ZnS nanoparticles influences the barrier height at the metal-organic film interface and causes a change in electrical conduction properties of LB films.     

多孔银钌合金催化剂的制备、表征和性能研究

以葡聚糖为软模板制备了多孔AgRu合金催化剂,利用X射线衍射仪和扫描电镜仪对其结构和形貌进行表征,并研究了其催化性能。结果表明,6种催化剂的催化产氢活性次序为Ag_9.2Ru>Ag_3.6Ru>Ag_4.0Ru>Ag_13.5-Ru>Ag_21.3Ru>Ag_22.4Ru。银钌原子比和催化剂形貌共同影响催化剂性能。其中选用Ag_9.2 Ru催化剂考察了NaBH₄和NaOH的质量分数对产氢速率的影响,研究结果表明,随NaBH₄和NaOH质量分数的增加,催化产氢速率降低。     

Microcapsules of PEGylated gold nanoparticles prepared by fluid-fluid interfacial assembly

Amphiphilic, PEGylated gold nanoparticles, of approximately 2 nm average core diameter, were synthesized by reduction of hydrogen tetrachloroaurate in the presence of the ligand (1-mercaptoundec-11-yl)tetra(ethylene glycol). These PEGylated gold nanoparticles were found to assemble cleanly at the oil-water interface. This self-assembly process gave a microencapsulated oil phase, water as the continuous phase, and a monolayer of gold nanoparticles at the oil-water interface. The capsules could be cross-linked from the organic phase by reaction of the chain-end hydroxyl groups of the PEG ligands with suitable electrophiles such as terephthaloyl chloride.     

Synthesis of Fe3O4@PbS hybrid nanoparticles through the combination of surface-initiated atom transfer radical polymerization and acidolysis by H2S

A versatile approach to fabricate nanoparticles with multiple functionalities through the combined use of both surface-initiated ATRP and acidolysis by H2S techniques was demonstrated. The hybrid nanoparticles exhibited the core-shell structure having the magnetite nanoparticles as the core and the polymethacrylate as the shell with PbS nanoparticles distributing in the shell. The structure and morphology of the synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical and magnetic properties of the nanoparticles were investigated by UV-Vis spectroscopy, photoluminescence spectroscopy and vibrating sample magnetometer (VSM), respectively. It is observed that the absorption and emission behaviors of the Fe3O4@PbS hybrid nanoparticles were seriously influenced by the ATRP time and the reaction time with H2S. The saturated magnetization (Ms) decreased with the increase of ATRP time due to the formation of thicker shells coating on the surfaces of magnetite nanoparticles.     

La0.67Sr0.33-xAgxMnO3的室温磁电阻效应

采用溶胶-凝胶(sol-gel)法制备了名义组分为La0.67Sr0.33-xAgrMnO3(x=0.15、0．20)的多晶样品,发现用Ag部分替代Sr后样品的室温磁电阻比替代前明显增大。在1．8T下,La0．67Sr0.18Ag0.15MnO3样品的磁电阻在330K出现峰值,其峰值为35％;对于La0．67Sr0.13Ag0.2 MnO3样品,磁电阻峰值为26％．且峰的宽度较大,在290～315K之间的磁电阻随着温度变化不大．因此显著提高了室温时样品的磁电阻和磁电阻的温度稳定性,另外．还提高了样品的磁场灵敏度。这对磁电阻的应用有很大意义。     

一步水热模板法制备Cu-TiO2异质结构纳米粒子（英文）

以聚乙二醇(PEG)为软模板剂,采用一步水热法合成了具有异质结构的铜–二氧化钛复合纳米粒子.利用X射线衍射谱(XRD)、透射电子显微镜(TEM)等分别对制备材料的相组成、微观结构进行了研究.结果表明,一步水热法制备的异质纳米粒子由单一立方相铜和锐钛矿相二氧化钛组成.高分辨透射电子显微镜(HRTEM)在单一粒子中观测到清晰的铜(101)和二氧化钛(111)晶面构成的界面.该界面有助于二氧化钛光生电子–空穴对的分离.同时,所制备纳米粒子的颗粒尺寸和光吸收特性可以通过改变PEG分子链长进行微调.本研究还对水热过程的反应机理进行了讨论,结果表明:PEG与铜氨络合物通过氢键连接,其链长对于粒子尺寸的影响在于PEG对Cu颗粒的尺寸进行的调节,而此过程中二氧化钛的晶粒尺寸并无明显变化.紫外–可见吸收光谱表明该异质纳米粒子与普通二氧化钛纳米粉体相比,对可见光区光谱有较为强烈的吸收.该界面纳米材料是一种有潜在应用价值的光催化材料和太阳能电池材料.     

One-step synthesis of silver nanoparticles at the air-water interface using different methods

Silver nanoparticles were synthesized in a one-step process at the air-AgNO(3) aqueous solution interface under Langmuir monolayers of 5,10,15,20-tetra-4-oxy(2-stearic acid) phenyl porphyrin (TSPP) at room temperature by using different methods including UV-light irradiation, ambient light irradiation, and formaldehyde gas reduction. It was found that parallel aligned one-dimensional (1D) chains composed of discrete silver nanoparticles with the size of 3-5?nm were formed under UV-light irradiation for a short time, while large areas of uniform silver spherical nanoparticles were formed under natural daylight illumination for several days or by formaldehyde gas treatment for several hours. The average size of the spherical nanoparticles ranges from 6.88 ± 0.46 to 11.10 ± 1.47?nm, depending on the experimental conditions. The 1D chains formed under UV-light irradiation result from the templating effect of parallel aligned linear supramolecular arrays formed by TSPP at the air-water interface, and rapid nucleation and growth of the nanoparticles. The formation of the uniform silver nanoparticles under daylight illumination or by formaldehyde gas treatment, however, should be ascribed to a kinetically controlled growth process of the nanoparticles.