丝蛋白多肽原位制备金纳米粒子的研究

用来自丝素蛋白的GAGAGAGY序列多肽原位还原氯金酸制备了粒径小于12 nm的球形金纳米粒子,用紫外-可见吸收光谱和透射电子显微镜对反应过程和产物进行了表征分析,探索制备条件对产物的影响。结果表明,多肽可发挥稳定剂的作用,使合成的金纳米溶液具有较好的稳定性;多肽和氯金酸的摩尔比为10:4时合成的粒子粒径大小合适且分布均匀;溶液碱性越强,还原反应速度越慢但金纳米粒径不受影响;反应温度升高,反应速率变快,紫外吸收峰蓝移。     

蒸馏水中采用脉冲激光烧蚀制备Ag纳米粒子胶体

采用脉冲激光（重复率为10Hz，能量密度为4．2J／cm^2）对蒸馏水中的Ag靶烧蚀不同时间后，制备得到Ag纳米粒子胶体，并对其进行紫外～可见分光光度计分析和透射电镜观察。结果表明：烧蚀时间为5～7．5min时，Ag纳米粒子粒径及分布随烧蚀时间呈减少趋势，烧蚀时间从7．5变化至15min时又随之增加，而烧蚀时间从15变化至25min时又随之减少：获得的纳米粒子浓度增高，且溶液中粒子的团聚率也增大：烧蚀时间为7．5min时，粒子粒径达到最小（D=14、48nm），粒径分布最小（8=25．8nm）。在实验基础上，应用纳米粒子对脉冲激光自吸收产生的“爆炸”与“熔化生长”模型解释了烧蚀时间对纳米粒子胶体的影响规律，证实通过改变烧蚀时间来控制纳米粒子尺寸和形貌、以及防止纳米粒子发生团聚的可行性。     

在生物相容性溶液体系中金纳米链的合成及其光谱性质

在生物相容性的葡萄糖-柠檬酸盐溶液体系中,研究了Au(III)离子的化学还原和金纳米粒子的各向异性生长;借助VIS/NIR光谱和透射电子显微镜的表征以及梯度离心分离技术,获得了具有多重孪晶、形状类似于马铃薯的链状金纳米粒子结构,其溶液具有2个表面等离子体共振吸收峰,分别呈现在光谱曲线较短和较长波长方向;研究了在含有球形和椭圆形金纳米粒子的溶液中由NaOH诱导所产生的自组装行为,获得了具有类似于金纳米棒光谱性质的金纳米链,其纵向共振吸收光谱峰位于大约800 nm波长处。简要讨论了在溶液体系中链状金纳米结构的形成和纳米粒子的自组装机理。     

等离子体法制备纳米Ni粉中热泳问题及其影响

利用等离子体法制备金属纳米镍粉。发现收集系统效率偏低，且平均粒度越小的粉末收得率越低。分析表明，对于纳米粒子不等温流场中的气固两相流输运过程，粒子沉降由重力沉降过渡到热泳沉降；粒子平均粒度从10μm下降到50nm时，热泳力与重力、马格纽斯升力的比值分别从0．07和0．02上升到2820和945，即热泳力因素占主导地位：温度梯度越大，粒子平均粒度越小。则热泳影响越显著，这是影响收得率的决定性因素。     

SDS／Vc／H2O微乳液中纳米金的合成

在SDS／Vc／H2O微乳液中用0．001mol·L^-1HAuCl4溶液代替组分水，以Vc作还原剂制备纳米金。紫外一可见光谱和扫描电镜实验结果表明，所制备的金纳米粒子的粒径在5-20nm之间；在固定SDS／Vc的质量比为50／50条件下，粒子的粒径随微乳液中HAuCl4（aq）含量的增加而增加。初步探讨了在SDS／Vc／H2O微乳液中合成纳米金的机制。     

反相微乳液中纳米金的可控合成及其机理研究

在AOT/正庚烷/氯金酸反相微乳液中,用水合肼作为还原剂制备了纳米金粒子, 用紫外-可见光谱和透射电镜进行分析,系统地研究了水和表面活性剂摩尔比 (ω=nH2O/nAOT)以及氯金酸浓度对粒径的影响。结果表明, 制备的纳米金粒子粒径在4~12 nm、单分散性好。纳米金粒径与ω值存在线性关系。氯金酸的浓度对粒径的影响比较复杂, 随着浓度增大, 粒径先减小后增大。用FT-IR红外光谱解释了AOT的磺酸基对纳米金粒子表面有强烈的吸附作用,从而对合成的纳米金粒子有着很强的保护作用     

负载型TiO2纳米薄膜电极光电催化氧化甲醇的研究

介绍了负载不同晶型TiO2薄膜电极的制备，并研究了聚乙二醇加入量、活化条件等对不同晶型、不同形貌、不同粒径纳米TiO2薄膜电极的光电催化活性的影响。结果表明：聚乙二醇加入量有一最佳值；且纳米级锐钛矿型TiO2和金红石型TiO2分别经600℃和400℃煅烧后，光电催化性能最好；粒径越小催化活性越高．当粒径小于25nm时，可显示出量子尺寸效应。     

AgI纳米粒子水溶胶的制备与表征

采用沉淀法制备了AgI纳米粒子水溶胶，对制备水溶胶的条件进行了系统的研究。TEM分析表明，AgI纳米粒子呈球形，粒径小于50nm，粒径分布均匀，无明显团聚现象；ED分析表明，AgI纳米粒子为多晶结构，其中有少量的发育良好的单晶颗粒存在。     

在可溶性聚合物体系中光化学法制备Pd纳米粒子的研究

研究了在可溶性聚合物体系中Pd纳米粒子的光化学合成.Pd(Ⅱ)-PEG-丙酮溶液以紫外波长300nm光辐照,获得了胶体Pd纳米粒子并对其进行TEM表征.结果表明,Pd粒子的平均粒径为1.8～5.7nm,具有好的分散性.研究了各种组分的影响,探讨了体系中Pd(Ⅱ)的快速光化学还原和纳米Pd粒子的稳定性机理.     

HF-PCVD法TiO2纳米晶的粒径与晶型控制

以TiCl4和O2为反应体系，采用高频等离子化学气相沉积(HF-PCVD)法制备了晶化完整的锐钛和金红石混晶型TiO2纳米晶，球形体的晶粒分散性良好，分布较为均匀：研究了控制粒径大小和晶相组成的关键反应条件。XPS，TEM，XRD结果显示：增加TiCl4进料量、延长停留时间均利于锐钛相向金红石相转化，但粒径有所增大：添加A1C13使金红石相含量较未掺杂时有较大幅度提高，且粒径随掺铝量增加而减小。本实验条件下，TiO2纳米晶的粒径为25nm～60nm，金红石相含量在12．O％～53．6％间可控。     

不同有机官能团对室温下纳米银形貌控制合成的影响

选择10种含有不同官能团的有机物为表面修饰剂,如聚乙烯吡咯烷酮、吐温-80、十二烷基硫酸钠、聚丙烯酸钠、聚乙二醇、山梨醇、十二烷基磺酸钠、聚乙烯醇、十二烷基苯磺酸钠和十六烷基三甲基溴化铵等,在室温下进行了平均粒径在2～131nm范围内纳米银颗粒的控制合成研究.有机修饰剂中含有的不同官能团对制得的纳米银形貌的影响主要取决于有机修饰剂的官能团特性和还原剂的还原能力.在不同还原条件下,含多醚键的聚乙二醇、吐温-80皆易于合成出平均粒径为几纳米、粒径分布窄、分散性好的纳米银.在弱还原剂条件下,十六烷基三甲基溴化铵诱导生成了三角形片状纳米银,但是在强还原剂存在条件下生成了粒状纳米银.粒径大于10m的纳米银晶体的生长是通过小颗粒的聚集与熔合而成,而不是经过小颗粒的溶解-沉积过程形成.     

修饰剂对液相还原法制备的纳米镍粒子形貌与尺寸的影响

180℃下,醋酸镍为前驱体,溶解在1,2-丙二醇溶剂中,以溶剂自身为还原剂,加入适量的修饰剂（如聚乙二醇系列（PEG-200,PEG-600,PEG-2000和PEG-6000）和十二烷基硫酸钠（SDS））,进行了粒径、形貌可控的纳米镍的合成．通过xRD,TEM和Fourier红外光谱（FTIR）对纳米镍进行了表征．结果表明,修饰剂的结构对纳米镍的粒径大小、粒径分布及形貌的影响很大．修饰剂PEG-200与PEG—600易于形成雪花状晶体,PEG-2000易于形成十二面体晶体,PEG-6000易于形成三角形薄片,SDS易于形成粒径较小的雪花状晶体和十二面晶体;PEG-600,PEG-6000与SDS复配后易于形成粒径较大的雪花状晶体．并对修饰剂的作用机理进行了讨论．     

纳米银的制备及其表征

采用液相化学还原法以抗坏血酸为还原剂,十二烷基硫酸钠为表面活性剂,在不同温度磁力搅拌的作用下,还原硝酸银溶液,制备成球形的纳米银粒子。利用紫外分光光度计考察反应温度、AgNO3浓度以及还原剂浓度对纳米银粒径的影响,利用XRD来观察纳米银粒子的晶型,用SEM观察纳米银粒子的表面结构以及粒径大小的分布范围。在AgNO3浓度为0.08mol/L、抗坏血酸浓度为0.1mol/L、温度为20℃时,制备的纳米银粉末纯净而均匀,平均粒径为30nm。     

Preparation of nickel nanoparticles in emulsion

The nickel nanoparticles with different sizes and spherical shape were prepared by the reduction of nickel sulfate with sodium borohydride in the water-in-oil emulsions of water/SDBS（sodium dodecylbenzene sulfonate）/n-pentanol/n-heptane. The effects of aging time, molar ratio of water to SDBS（R） and the concentration of nickel sulfate on the size of particles were studied. The samples were characterized by transmission electron microscopy（TEM） and inductively coupled plasma spectrometry（ICP）. The results show that the average particle size changes from 20 to 40 nm by adjusting aging time （15-30 min） and R （9-11.5）. The concentration of nickel sulfate of 1.0 mol/L is the favorite condition.     

Ag-Cu合金纳米颗粒的低温合成与热学性能

采用一种简单的低温化学还原方法,在水溶液中利用NaBH4作为还原剂还原醋酸或硫酸铜,制备了Ag-Cu纳米颗粒.反应过程中通入氮气来防止生成的合金被氧化.采用XRD、紫外-可见光谱、颗粒尺寸测试、EDS分析、TG-DTA分析和SEM观察等手段来表征合成的Ag-Cu纳米颗粒.XRD分析表明,所合成的Ag-Cu纳米颗粒的晶粒尺寸为15nm左右.紫外-可见光谱分析证实了纳米颗粒的生成.EDS分析表明,样品中存在Ag和Cu.SEM观察表明,所制备的样品的平均晶粒尺寸为40 nm.TG-DTA研究表明,合金的熔点与颗粒尺寸有关.     

表面活性剂对球磨法制备纳米Sb2O3粉末的影响

采用球磨法制备纳米Sb2O3粉末,研究表面活性剂对制备纳米Sb2O3的影响。采用X射线衍射仪、透射电子显微镜、红外光谱仪研究了球磨产物的物相组成、颗粒形貌以及平均粒径。研究结果表明表面活性剂对产物的Sb2O3含量、结晶度、粒径大小、形貌以及分散性具有显著地影响。当硬脂酸、辛基酚聚氧乙烯醚、聚丙烯酸钠作为表面活性剂时,球磨产物中Sb2O3的含量低于92%,颗粒大小不均匀,甚至出现团聚现象。当辛基酚聚氧乙烯醚与聚丙烯酸钠复配作为表面活性剂时,产物中Sb2O3含量为94%,颗粒形貌不规则。当聚丙烯酸钠与硬脂酸复配作为表面活性剂时,球磨产物中Sb2O3的含量达99%以上,分散性最好,粒径分布在10~20 nm之间,平均粒径15 nm左右。     

The effect of Au/Ag ratios on surface composition and optical properties of co-sputtered alloy nanoparticles in Au–Ag:SiO2 thin films

Gold–silver alloy nanoparticles with various Au concentrations in sputtered SiO₂ thin films were synthesized by using RF reactive magnetron co-sputtering and then heat-treated in reducing Ar + H₂ atmosphere at different temperatures. The UV–visible absorption spectra of the bimetallic systems confirmed the formation of alloy nanoparticles. The optical absorption of the Au–Ag alloy nanoparticles exhibited only one plasmon resonance absorption peak located at 450 nm between the absorption bands of pure Au and Ag nanoparticles at 400 and 520 nm, respectively, for the thin films annealed at 800 °C. The maximum absorption wavelength of the surface plasmon band showed a red shift with increasing Au content. XPS results indicated that the alloys were in metallic state, and they had a greater tendency to lose electrons as compared to their corresponding monometallic state. Moreover, the positive and negative shift of the Au(4f) core-level binding energies was observed for low and high Au concentration, respectively. Also a negative shift of the Ag(3d) binding energies was increased by increasing Au concentration. Diffusion of the particles toward the surface by increasing the temperature has also been illustrated by AFM images. Based on AFM observations, we have found that the particle size reduced from 35 to 20 nm by increasing the annealing temperature from 600 to 800 °C, while particle size increased by increasing Au concentration in films. In addition, lateral force microscopy (LFM) analysis showed that the alloy particles were uniformly distributed on the surface.     

Growing and stability of gold nanoparticles and their functionalization by cysteine

Gold nanoparticles in aqueous dispersion were prepared using the trisodium citrate reduction method to control the size of particles by changing the concentration of HAuCl₄. The average particle size measured by DLS is higher than that obtained by TEM at a zeta potential of -40 mV. When trisodium citrate concentration is kept constant, the particle size increases with gold concentration. The kinetics of growth was studied and apparent kinetic rate constants were determined at various gold/citrate ratios. Gold nanoparticles were attached to silanized glass surfaces; Au rods were grown (ca. 200 nm) by adding more precursors and the rods’ growth rate was monitored by UV-Vis spectroscopy as well as by AFM. Surface functionalization of gold surface was influenced by cysteine. The surface modification by cysteine at pH=6.0 results in aggregation and the red shift of absorption maximum is nearly 200 nm. When glutathione molecules are bound onto the cysteinelinked Au rods on the glass surface, the spectral shift reaches only an amount of 5–10 nm, because the surface attachment hinders the tendency to aggregate.     

Direct current electrodeposition of Zn and Zn–SiC nanocomposite coatings

Pure Zn and Zn matrix composite coatings containing nano-sized SiC particles with an average size of 50 nm were prepared from the zinc sulphate bath. The effect of the particle concentration and current density on the amount of particles embedded was examined. Electron microscopic studies revealed that the coating morphology was modified by the presence of SiC nanoparticles. Corrosion resistance properties of the coatings were studied using a potentiodynamic polarisation technique in 1M NaCl solution. It was established that agglomeration of nanoparticles worsens corrosion resistance properties of Zn–SiC coatings. However, the presence of well dispersed nanoparticles significantly improves the corrosion resistance of the zinc. Incorporation of SiC nanoparticles also improves the microhardness of the zinc matrix.