MoO3纳米粒子水溶胶的制备与光致变色性质研究

采用沉淀法制备了MoO3纳米粒子水溶胶,对制备水溶胶的条件进行了系统地研究.TEM分析表明,MoO3纳米粒子呈球形,粒径约为60nm,粒度分布均匀;ED分析表明,MoO3纳米粒子为多晶结构.UV-VIS分析表明,MoO3纳米粒子水溶胶具有一定的光致变色特性.     

MoO3纳米有机溶胶的制备与光致变色性质研究

采用表面活性剂CTAB对MoO3水溶胶中的纳米粒子进行表面修饰，通过正戊醇萃取制备了MoO3纳米有机溶胶，对制备有机溶胶的条件进行了系统地研究。TEM分析表明，MoO3纳米粒子呈球形，粒径约为40nm，粒度分布均匀。ED分析表明，MoO3纳米粒子为多晶结构。UV-VIS分析表明，MoO3纳米有机溶胶具有较好的光致变色特性。     

AgCl与Cu^2＋共存纳米溶胶的制备与表征

采用沉淀法制备了AgCl与Cu^2 共存的纳米水溶胶，油酸萃取并包覆AgCl与Cu^2 共存的纳米水溶胶，制备了AgCl与Cu^2 共存的纳米有机溶胶，对水溶胶和有机溶胶的制备条件进行了系统的研究。TEM分析表明，AgCl纳米粒子呈球形，粒径约50nm，粒度分布均匀，无明显团聚现象。ED分析表明，AgCl纳米粒子为多晶结构，其中有少量的单晶存在。表面包覆油酸的AgCl纳米粒子易溶于弱极性溶剂，难溶于极性溶剂。     

CeO2纳米水溶胶的制备

采用胶溶法合成了纳米CeO2水溶胶，探讨了合成CeO2水溶胶的最佳实验条件，研究了pH值、反应物浓度、水浴温度对胶溶过程的影响。TEM3分析表明：所制备的水溶胶中的CeO2纳米粒子呈球形，约3nm，粒径分布均匀，无明显团聚现象；ED分析表明，CeO2纳米粒子为多晶结构，并有少量单晶结构。     

水热晶化法制备CeO2纳米晶

用水热晶化法制备了Ceo2纳米晶。X射线衍射（XRD）分析表明，所合成的CeO2纳米晶属于立方晶系，空间群为O^5H-FM3M。透射电镜（TEM）分析表明，CeO2纳米粒子呈球形，平均粒径小于100nm。实验发现，水热处理温度升高，CeO2粒子中含水量减少。CeO2纳米晶的相对密度随水热处理温度的升高而略有增大。     

纳米氧化物La0.8Sr0.2MnO3的制备研究

用添加表面活性剂的苹果酸溶胶凝胶法制备出纳米钙钛石型氧化物La0.8Sr0.2MnO3。通过差热热失重分析,确定了氧化物的焙烧制度。XRD分析表明,所烧制的氧化物样品特征衍射峰明显,杂峰少,晶形完整,其物相为钙钛石结构。表面活性剂因其亲油基团和亲水基团与胶体粒子可以发生复杂的相互作用,形成胶束和胶团,保护了胶体粒子不长大,从而有效地减小氧化物粉料的颗粒粒径,并且在纳米材料的制备过程中能显著降低纳米微粒的表面张力,从而可防止原生粒子团聚,所以在溶胶的制备过程中添加了表面活性剂聚乙烯醇(PVA)。根据谢乐公式计算得出,添加了PVA后,氧化物粉料的粒径约为17nm。TEM分析表明,聚乙烯醇可以作为纳米氧化物粉体La0.8Sr0.2MnO3的分散剂,添加适量的PVA可使纳米粒子的团聚现象得到了明显改善。     

改性纳米CaCO3复合粒子的制备、表征及性能

采用含有纳米硅溶胶的纳米碳酸钙悬浮液在超声波处理及加热条件下,硅溶胶发生缩合反应从而沉积在纳米碳酸钙粒子表面的溶胶-凝胶沉淀法,制备出性能稳定的纳米碳酸钙/二氧化硅复合粒子.通过红外光谱(FTIR)、TEM分析、zeta电位测定以及TGA分析,表征了硅溶胶与纳米CaCO3粒子之间的杂化作用,研究了改性纳米CaCO3复合粒子水分散液的稳定性和粒径、两种纳米粒子之间的包覆作用、杂化作用以及改性后纳米CaCO3复合粒子的热稳定性.同时研究发现,改性后的无机纳米CaCO3复合粒子在聚氨酯脲水分散液中具有很好的分散性.     

树莓形SiO2–TiO2纳米粒子的制备及其在光学涂层中的应用

目的 提高Ti O₂纳米粒子在复合光学薄膜中的分散性及光催化自清洁效率。方法 以通过St?ber法制备的粒径为70、140 nm的Si O₂粒子与酸催化法制备的粒径为5 nm的Ti O₂粒子为原料,分别使用硅烷偶联剂3–氨丙基三乙氧基硅烷（APTES,或KH550）与γ–缩水甘油醚氧丙基三乙氧基硅烷（GLYMO,或KH560）对2种纳米粒子进行表面改性。通过2种粒子表面的化学基团之间的化学键,将2种粒子进行偶联,形成了小粒子包覆大粒子的树莓形结构,并利用溶胶–凝胶法制备了光学涂层,通过紫外–可见分光光度计、红外光谱仪、激光粒度仪等多种表征设备对制备的复合纳米粒子及构筑的薄膜的结构、形貌和性能进行了分析。结果 粒径较小的Ti O₂纳米粒子通过表面基团的反应均匀地包覆在粒径较大的Ti O₂纳米粒子表面形成树莓形的复合结构,构筑的薄膜具有较高的透光率（>90%）,较好地保留了玻璃基底的透过率,在紫外辐照条件下可在120 min内完全降解有机污染物,具有高效的光催化自清洁功能。水...     

溶胶-凝胶法制备纳米复合Mo-La2O3阴极

采用溶胶-凝胶法制备出平均粒径小于60nm的Mo-La2O3粉末。将所制备出的纳米复合Mo-La2O3粉末经冷压、热压工艺后烧结成纳米复合Mo-La2O3阴极。发现用溶胶-凝胶法制备的Mo-La2O3阴极组织均匀，晶粒细小，La2O3粒子晶粒大多在100nm以下，且弥散分布在晶内及晶界上。在燃弧实验中发现用溶胶．凝胶法制备的纳米复合Mo-La2O3阴极击穿点分布存阴极表面的大部分面积上，烧蚀坑浅，且击穿优先发生在La2O3相上。     

γ射线辐照－水热处理法制备纳米金属粉末

用γ射线辐照－水热处理法制备出８ｎｍＡｇ粉、１６ｎｍＣｕ粉和１０ｎｍＰｄ粉．研究了实验条件对Ａｇ粉粒径的影响．确定了制备纳米Ｃｕ粉的工艺参数，发现用ＥＤＴＡ络合Ｃｕ离子，有利于制备粒径较小的纳米Ｃｕ粉，在不同条件下可获得球形和针形的纳米Ｃｕ粒子．     

Formation of silver nanoparticles in solutions of carboxymethylcellulose

An investigation is reported on the relation between the size and ζ potential for silver nanoparticles prepared in aqueous solution of carboxymethylcellulose to pH of the solution by virtue of dynamic light dissipation. The changes in the size distribution for nanoparticles and their ζ potential were monitored over time. The size of particles was found to degrease linearly with increasing pH; a similar effect was created by the maturation of colloidal solution. The ζ potential of the maturation process tended to take an identical value for all hydrosol samples studied. A procedure is proposed for the numerical calculation of the relative concentration of nanoparticles that is applicable for the investigation of samples with various types of distribution for particle sizes. The degree of reduction for silver ions was found to depend significantly on the quantity of AgNO₃ presented and the ration between the precursor and the reducing agent.     

The Formation of Metal-Catalyst Nanoparticles by the Hydrosol Method in TWEEN-20 Aqueous Solution and Conditions for Their Uniform Distribution on a Carbon Carrier Surface

Conditions for the formation of metal-catalyst nanoparticles in an aqueous medium by the hydrosol method in the presence of surfactant are studied. Based on the study of the colloidal chemical properties of the preparation TWEEN-20, which is a polyoxyethylene sorbitan monolaurate containing, in addition to TWEEN-20 itself, impurities of other fatty alkyl esters and fatty acids, the possibility of its use in the synthesis of an electrocatalyst, including platinum, as a dispersion stabilizer of freshly formed particles is shown. The formation of platinum nanoparticles and their uniform distribution over the surface of the carbon carrier is confirmed by transmission electron microscopy, small-angle X-ray scattering, and X-ray-diffraction analysis.     

Synthesis, processing and forming gold structures from a 0.1 wt. % concentration solution

A very low concentration (≈0.1 wt. %) of spherical 15nm diameter gold nanoparticles were produced by the sodium citrate reduction method and later transferred to ethanol using poly vinyl pyrrolidone (PVP) as a stabilizing agent. The alcosol was then subjected to electrohydrodynamic atomisation to generate fine droplets with an average droplet diameter of < 30μm and deposited on substrates accordingly. With the assistance of various deposition methods, three different microstructures were produced. Firstly, the droplets produced by atomisation with the help of an electric field were deposited at various times on a substrate to fabricate gold films with a thickness range of ~500nm to 2000nm. Secondly, the droplets were deposited on a moving table which is computer controlled to form an array of inter-connected droplets, thus enabling us to pattern microstructures containing gold nanoparticles of different geometries (electrohydrodynamic atomisation printing). Thirdly, to reduce the track size as well as to form a dense assembly of particles in the microstructures templates were used in conjunction with electrohydrodynamic atomisation (templateassisted patterning). In order to encapsulate gold nanoparticles in a fibre a co-axial needle set-up was used with a polyethylene oxide (PEO) and polyethylene glycol (PEG) mixture as the encapsulating media. Lastly, a gold hydrosol was used to produce near-monodisperse gold microbubbles with the help of a T-junction device having an average diameter of ≈150μm. The ability to generate such a range of structures starting from a very low concentration of gold is a significant achievement.     

Steric hindrance as a rate controlling step in stress corrosion cracking

The effect of steric hindrance in the stress corrosion cracking (SCC) of Ag-15Pd (a/o) in AgI forming solutions was studied at room temperature. The solutions used were 1 M KI at a potential higher than that of AgI formation, and iodine dissolved in different n-alcohols. It was found that Ag-15Pd (a/o) is susceptible to intergranular stress corrosion cracking in those solutions. The SCC susceptibility measured as percentage of elongation to rupture and crack propagation rate is related to the size of the active species. While in KI aqueous solutions, as well as in iodine saturated benzene or iodine saturated toluene, the rate controlling step (RCS) was the reaction at the tip of the crack, in alcoholic-iodine solutions, the diffusion rate of the iodine containing molecules became the RCS.     

A changed state of silver nanoparticles upon the adsorption of acrylic acid and low-temperature treatment

Plasma-resonance absorption spectra of silver hydrosol were recorded and analyzed to estimate the influences of acrylic acid (AA) as an additive and subsequent low-temperature treatment (LTT) of the sol at 77 K on the state of silver nanoparticles. It was found that AA adsorbs in two forms with different orientations of its molecules. Low-temperature treatment resulted in aggregation of particles because of their more defective surfaces, which is characterized by the damping factor of plasmon vibrations. In the adsorption of AA, the damping factor also increases, but the cryoaggregation of particles decreases. Original Russian Text ? E.A. Kononova, Ngia Nguen, I.I. Mikhalenko, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 2, pp. 183–186.     

AgI/BiPO4异质结的原位制备及光催化性能

采用水热合成法制备了磷酸铋(BiPO4),通过沉淀法成功将AgI负载于BiPO4表面制备了AgI/BiPO4异质结。采用X射线衍射仪(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)等对AgI/BiPO4异质结结构和组成进行了表征;用表面光电压谱(SPS)对异质结光催化剂的光生电荷分离特性进行了研究;考察了AgI/BiPO4异质结光催化剂对模拟污染物罗丹明B的催化降解性能。结果表明,当AgI/BiPO4摩尔比为1.2%时,异质结光催化剂的光生电子-空穴分离速率最高,对罗丹明B的光催化降解性能最好。光催化过程中主要活性自由基为超氧自由基.O2^-,h⁺空穴和.OH自由基是起次要作用的活性自由基。