前驱物热稳定性对氧化铁/氧化锡制备的影响

氧化铁纳米复合材料具有优越的磁学和催化性能,近年来在癌症诊断及治疗[1-3]、污染治理[4-6]、电磁屏蔽[7-8]等多个领域得到广泛研究.目前有许多研究集中于如何对复合材料的组成、结构和形貌进行设计合成,例如:利用机械球磨法将SnO2和α-Fe2O3粉体混合制备α-Fe2O3/SnO2 复合材料[9];通过共沉淀法将SnO2复合在α-Fe2O3 的表面[4];或者在Fe3O4表面复合一层C和相应的盐,然后通过煅烧制备Fe3O4/ZrO2和Fe3O4/TiO2微球[10-11].     

溶胶-凝胶前驱体喷雾干燥法制备钠离子电池Na_2Ti_3O_7@MWCNTs负极材料

本文采用溶胶-凝胶前驱体喷雾干燥法制备了Na2Ti3O7@MWCNTs(多壁碳纳米管)复合材料,用于钠离子电池的负极.这种方法得到的Na2Ti3O7球形壳层包裹纳米Na2Ti3O7@MWCNTs复合材料的结构与用固相烧结法、简单溶胶-凝胶法制备的Na2Ti3O7-MWCNTs复合材料在电化学性能上相比,具有倍率性能好、小电流下50次循环后比容量衰减小等优势.     

溶胶-凝胶法可控制备氧化锡纳米晶包覆碳纳米管

采用溶胶-凝胶法制备了氧化锡纳米晶包覆的碳纳米管。自由Sn4+离子从稳定的Sn柠檬酸配合物中缓慢释放出来,迁移到碳纳米管上,并在碳纳米管上沉积形成了SnO2纳米晶,沉积过程完全为异相成核方式,在碳纳米管外并没有发现单独的SnO2纳米晶。这种溶胶-凝胶方法还可以用来制备无氯离子污染的、低团聚的纯SnO2纳米晶。     

ZnO纳米粒子结构对光电量子限域特性的影响

Zn O作为一种宽禁带 (3 .3 6e V)高激子结合能 (60 me V)的半导体材料已引起人们的关注 .Zn O纳米粒子的比表面积较大 ,表面活性较高 ,对周围环境敏感 ,使其成为传感器制作中最有前途的材料[1] ,还在太阳能转换[2 ] 、发光材料[3] 、半导体表面修饰与敏化[4 ] 、纳米电子学以及分子电子学器件[5] 等领域显示出广阔的应用前景 .制约这些应用的关键是 Zn O纳米粒子表面和界面的电子结构和电荷转移行为 ,但有关此方面的报道较少 .本文用溶胶 -凝胶法制备了不同粒径的 Zn O纳米粒子 ,应用表面光电压谱 (SPS)和场诱导表面光电压谱 (FISPS…     

炸药爆轰合成纳米石墨的红外光谱研究

石墨是碳材料中最常见的结晶状态,它具有耐高温、抗腐蚀、自润滑、无毒及价格低廉等特点,广泛应用于润滑剂和添加剂等方面^[1].由于高纯纳米石墨粉在某些高新技术领域中有较好的应用前景,近些年来得到开发和应用,如制成复合导电材料、吸波材料及储氢材料等^[2].以前有学者用纳米金刚石粉加热相转变^[3]和高能球磨^[4,5]的方法制备了纳米石墨,在制备碳纳米管时也有石墨的纳米粒子生成^[6].但用这几种方法制备纳米石墨,既费时又消耗较大能量,成本非常高.     

球形α-Fe2O3纳米粉体的超声水解法合成与表征

0引言纳米Fe2O3因在磁性、气敏、催化、染料、抗腐蚀等领域显示出广阔的应用前景而备受瞩目[1￣3]。Fe2O3存在α-Fe2O3、β-Fe2O3、γ-Fe2O3、ε-Fe2O3等多种构型,它们在性能上差异较大,如α-Fe2O3具有良好的磁性和气敏性,可用作气敏材料和磁记录材料;γ-Fe2O3具有独特的电、磁、光等性质而在信息存贮器、彩色显像管、生物处理、磁制冷等方面得到广泛应用。由于其各种应用都与性能有直接关系,所以研究Fe2O3的制备方法具有重要意义。尽管不少学者采用溶胶-凝胶法[4]、电化学合成法[5]、微波辐射法[6]、燃烧合成法[7]、水热法等[8]不…     

欧洲聚合物联合会(EPF)第二届夏季大学“纳米结构聚合物材料”讲座

时间 :2 0 0 3年 5月 2 5～ 3 0日　地点 :意大利Ｇａｒｇｎａｎｏ(ＢＳ)讲题内容 :纳米结构材料综论 ;纳米材料模型化 ;超分子聚合物 ;控制有序纳米结构的聚合物络合物 ;树枝状大分子纳米材料 ;嵌段共聚物作为纳米材料 ;纳米结构热固性树脂 ;碳纳米管 聚合物纳米复合材料新性能 ;碳纳米管在聚合物中的应用 ;聚合物 层状硅酸盐纳米复合材料 ;纳米复合材料的流变行为 ;用溶胶 凝胶技术制备杂混化合物 ;多面体齐聚物硅倍半烷 (ＰＯＳＳ)杂化聚合物材料 ;柱状纳米材料与燃料电池 ;反应性加工制备杂化化合物 ;预成形纳米填料用于原位合成 ;生…     

水热法制备SnO2/α-Fe2O3纳米复合材料

用α-Fe2O3纳米粒子作为前驱物,以SnC l4和NaOH作为反应试剂,通过简单的水热法制备了SnO2/α-Fe2O3纳米复合材料。SnO2/α-Fe2O3纳米复合材料具有有趣的形貌:直径约为20nm的SnO2纳米棒以α-Fe2O3纳米粒子为中心向四周辐射生长。利用X-ray粉末衍射(XRD),透射电镜(TEM)和扫描电镜(SEM)等测试手段对样品的成份、结构、形貌和尺寸进行了表征,初步探讨了SnO2/α-Fe2O3纳米复合材料的形成机理。     

铜纳米粒子在碳纳米管上的原位生长及对过氧化氢电催化性能的研究

采用一种温和且有效的方法,将聚丙烯酸非共价修饰到碳纳米管上,并以其为模板,在碳纳米管上原位均匀的生长铜纳米粒子,制备了铜/聚丙烯酸/碳纳米管(Cu/PAA/CNT)纳米复合材料,并以此材料构建了一种新型的非酶H2O2传感器,研究了其对H2O2的电催化行为。结果表明:铜纳米粒子较均匀的生长在碳纳米管上,制备的纳米复合材料修饰到电极表面对H2O2表现出良好的电流响应,可实现对H2O2的灵敏测定,其响应电流与H2O2的浓度在1.9×10-6～8.0×10-4mol/L范围内呈良好的线性关系,检测限达6.3×10-7mol/L。     

纳米复合材料K_8[γ-SiW_(10)O_(36)]·12H_2O/ZrO_2微波增强光催化降解二甲酚橙

通过溶胶.凝胶再程序升温熔剂热一步法制备了K8[γ-SiW10O36]·12H2O/ZrO2纳米复合光催化材料,采用FT-IR、XRD、ICP-AES和氮气吸附-脱附测定等测试手段对其组成、结构、形貌等进行了表征.结果表明,复合材料中杂多酸的基本结构未发生明显变化,并且该复合材料比表面积增大(120.061m2/g)的同时还具有孔结构,平均孔径约为3.7nm.在微波无极灯照射下,以微波增强光催化降解二甲酚橙为模型反应,研究了该纳米复合材料微波增强光催化性能,结果表明,在微波作用下,复合光催化材料K8[γ-SiW10O36]·12H2O/ZrO2的光催化活性显著增强.     

ZnO and carbon nanocomposites for enhanced photoelectrochemical sensing activity: influence of the carbon content

Journal of Solid State Electrochemistry - In this work, carbon and zinc oxide (ZnO:C) nanocomposites were obtained by a hydrothermal reaction process. ZnO nanoparticles were first prepared by a...     

可循环SERS基底ZnO/Ag纳米材料合成和表征

利用简易、绿色、一锅煮的水热法合成了花状氧化锌/银复合纳米材料。然后利用各种光谱和显微技术对复合物进行了表征,并讨论了其表面增强拉曼（SERS）性能和光催化性能。结果表明氢氧化钠的量对于这种复合纳米材料的形貌和性能具有重要的调节作用。和其他形貌的氧化锌/银复合纳米材料相比较,花状氧化锌/银复合纳米材料具有最佳的光催化性能。同时进一步以花状氧化锌/银复合纳米材料作为SERS基底研究其表面增强拉曼性能,结果表明这种复合材料同时具有很好的表面增强拉曼性能。光催化和表面增强拉曼结果表明这种花状氧化锌/银复合纳米材料有望在有机物检测中作为一种具有很好的可循环性的新表面增强拉曼基底材料。     

可循环SERS基底ZnO/Ag纳米材料合成和表征

利用简易、绿色、一锅煮的水热法合成了花状氧化锌/银复合纳米材料。然后利用各种光谱和显微技术对复合物进行了表征,并讨论了其表面增强拉曼(SERS)性能和光催化性能。结果表明氢氧化钠的量对于这种复合纳米材料的形貌和性能具有重要的调节作用。和其他形貌的氧化锌/银复合纳米材料相比较,花状氧化锌/银复合纳米材料具有最佳的光催化性能。同时进一步以花状氧化锌/银复合纳米材料作为SERS基底研究其表面增强拉曼性能,结果表明这种复合材料同时具有很好的表面增强拉曼性能。光催化和表面增强拉曼结果表明这种花状氧化锌/银复合纳米材料有望在有机物检测中作为一种具有很好的可循环性的新表面增强拉曼基底材料。     

Facile polystyrene/ZnO/Fe3O4 nanocomposites prepared via a hydrothermal approach for enhancement of MB dye degradation

Research on Chemical Intermediates - In this present work, polystyrene/ZnO and polystyrene/ZnO/Fe3O4 nanocomposites (NCs) were prepared by a hydrothermal synthesis method. The crystalline nature of...     

Hierarchical Ag/ZnO micro/nanostructure: Green synthesis and enhanced photocatalytic performance

Ag/ZnO metal-semiconductor nanocomposites with hierarchical micro/nanostructure have been prepared by the hydrothermal synthesis in the presence of bovine serum albumin (BSA). The results suggest that this biomolecule-assisted hydrothermal method is an efficient route for the fabrication of Ag/ZnO nanocomposites by using BSA both a shape controller and a reducing agent of Ag⁺ ions. Moreover, Ag nanoparticles on the ZnO act as electron sinks, improving the separation of photogenerated electrons and holes, increasing the surface hydroxyl contents of ZnO, facilitating trapping the photoinduced electrons and holes to form more active hydroxyl radicals, and thus, enhancing the photocatalytic efficiency of ZnO. This is a good example for the organic combination of green chemistry and functional materials.     

Photocatalytic Activity of Nanocomposites of ZnO and Multi-Walled Carbon Nanotubes for Dye Degradation

Nanocomposites of ZnO and multi-walled carbon nanotubes (MWNTs) were prepared via electrostatic interaction and in situ hydrothermal synthesis approaches. The ZnO/MWNTs nanocomposites display relatively higher photocatalytic activity than ZnO nanoparticles for the degradation of Rhodamine B. Therein, MWNTs, acting as a photogenerated electron acceptor, retard the recombination of photoinduced electron and hole. The experimental results show that the photocatalytic activity of the ZnO/MWNTs nanocomposites strongly depends on the synthetic route, which is probably due to the difference of surface states resulted from the different preparation processes.     

Direct growth of flexible LiMn2O4/CNT lithium-ion cathodes

Flexible, binder-free LiMn(2)O(4)/CNT nanocomposites with good reversible capability and cycling stability were fabricated by in-situ hydrothermal growth for flexible lithium battery applications.     

Morphology‐controlled Fabrication of SnO2/ZnO Nanocomposites with Enhanced Photocatalytic Performance

In this work, a series of novel SnO₂/ZnO nanocomposites with different morphologies were fabricated via a facile hydrothermal technique followed by calcination in air. The morphological, structural and photocatalytic properties of the SnO₂/ZnO nanocomposites were studied using different methods. The results showed that the synthesized nanocomposites possessed crystal phases of wurtzite hexagonal phase ZnO and tetragonal rutile phase SnO₂. In addition, the morphologies of SnO₂/ZnO nanocomposites strongly depended on the molar ratios of Sn and Zn. Compared with ZnO and SnO₂, the SnO₂/ZnO nanocomposites exhibited considerably higher degradation efficiency for the photodegradation of methylene blue and quinolone antibiotics under mercury lamp irradiation. The SZ‐2 nanospheres exhibited the highest degradation efficiency of 95.81%, which was about 2.63 times higher than that of ZnO nanoparticles. Moreover, the trapping experiments confirmed that ˙OH played the dominant role in MB degradation. Finally, the charge carriers potential transfer pathway and photocatalytic degradation mechanism were put forward. This study provides an economical way to prepare hybrid nanocomposites with controlled morphology for practical applications in the photocatalytic degradation of organic dyes and residual antibiotics.     

Preparation and properties of polymer/zinc oxide nanocomposites using functionalized zinc oxide quantum dots

Poly(methyl methacrylate) (PMMA)/zinc oxide (ZnO) or carbazole polymer (PCEM)/ZnO nanocomposites, which are composed of high molecular weight PMMA or PCEM with narrow molecular weight distributions and ZnO nanoparticles, were successfully prepared by atom transfer radical polymerization (ATRP) initiated by 2-bromo-2-methylpropionyl (BMP) group (ZnBM) introduced onto the ZnO nanoparticle surfaces. Introduction of the BMP group onto the ZnO surfaces was achieved by esterification of OH group of the ZnO surfaces. The chemically attached OH group-having ZnO nanoparticles (ZnHM) were fabricated by sol-gel reaction from zinc acetate dihydrate, followed by treatment of the ZnO nanoparticles with 2-hydroxypropionic acid (HPA). The ZnHM nanoparticles showed one UV absorption and two emission bands: UV emission peak and broad visible emission band, while the ZnBM exhibited broad UV absorption and no emission spectra. The PMMA/ZnO nanocomposites displayed UV absorption and photoluminescent (PL) band with blue emission on the basis of the ZnHM nanoparticles, where the ZnO nanoparticles dispersed homogeneously in the PMMA matrix. The PCEM/ZnO nanocomposites depicted UV emission peak due to the carbazole unit in the UV range, but no visible emission. Thermal properties of the PMMA/ZnO nanocomposites were improved by dispersion of the ZnO nanoparticles into the PMMA, but the PCEM/ZnO nanocomposites showed no improvement of the thermal properties.     

An experimental investigation on the conductive behavior of carbon nanotube-reinforced natural polymer nanocomposites

It is well known that carbon nanotubes (CNTs) have excellent electrical properties and can be used as the nanofiller in natural polymers to produce conductive CNT/polymer nanocomposites. In this study, the conductive behavior of CNT-reinforced natural polymer nanocomposites was investigated. The effect of CNT concentration on the conductivity of CNT/natural polymer nanocomposites was also investigated. The natural polymers used were plasticized starch (PS) and chitosan (CS). FTIR spectroscopy was used to examine the interactions between PS, CS, and CNTs. TEM analysis on both nanocomposites were made to study the dispersion states of CNTs in both polymers. The results showed that the surface resistivities of both CNT/PS and CNT/CS nanocomposites decreased steeply with increasing CNT concentration. Particularly, the CNT/CS nanocomposites showed a better conductivity than the CNT/PS composites at the same CNT concentration. The TEM result showed that CNT/CS nanocomposites had better dispersibility and formation of fully connected, three-dimensional network structures between the CNTs than the CNT/PS nanocomposites, which results in the superior conductive property of CNT/CS nanocomposites compared to the CNT/PS nanocomposites.