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生物矿化合成纳米针状SiO2 总被引:16,自引:0,他引:16
利用少量有机大分子可控制大分子成核、生长,最后形成生物矿化纳米结构材料[1].这些合成的纳米结构材料有许多重要的性质,如流动性和运输行为、催化活性、分离效率、粘附特性、储存特性和从"智能"胶体中释放的动力学特性等[2]. 相似文献
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以硝酸铅和硫代乙酰胺为前体,十二烷基苯磺酸钠(SDBS)扮演了前体和表面活性剂的双重角色,制备出硫化铅纳米带。 采用透射电子显微镜、X射线衍射和光致发光对所制备的纳米带进行了表征。 结果表明,中间产物PbSO4在水热条件下对PbS纳米带的进一步形成主要起到模板作用。 进一步考察了纳米带形成机理,结果表明,中间产物PbSO4对表面活性剂是有制约性的,而当改变中间产物保持条件不变的情况下,模板效应失控,只能得到不规则的微晶体。 实验结果表明,制备硫化铅纳米带反应速度较为缓慢,易于控制,为制备不同形貌纳米带提供了一种有效方法。 相似文献
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模板法合成纳米结构材料 总被引:9,自引:0,他引:9
模板法(包括硬模板和软模板法)是制备纳米结构材料的常用方法,可用来制备多种物质的各种形状(如:球形粒子、一维纳米棒、纳米线、纳米管以及二维有序阵列等)的纳米结构,近年来关于这一领域的研究较为活跃。本文介绍了近年来利用氧化铝、二氧化硅、碳纳米管、表面活性剂、聚合物、生物分子等作模板制备多种物质的纳米结构材料的一些进展。 相似文献
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生物鸡蛋内膜结构氧化铈材料的合成与表征 总被引:1,自引:0,他引:1
采用生物废弃材料鸡蛋内膜为模板, 选取适当浓度的硝酸铈溶液, 调节pH值, 通过两步浸渍, 经有机-无机界面上的表面化学及生物化学过程的交互作用, 使生物膜与稀土元素铈均匀结合, 并于550 ℃煅烧, 合成了管状分级多孔氧化铈纳米材料. 通过傅里叶变换红外光谱(FTIR)、热重分析(TGA)和场发射扫描电镜(FESEM)等测试手段对材料进行了表征. 结果表明, 该材料具有独特的纤维网络状生物形貌, 是由内径500 nm、管壁厚约为250 nm的微米级氧化铈中空管所组成, 其壁上含有大量1~5 nm孔径的颗粒堆积孔. 考察了该材料对酸性品红染料脱色反应的催化活性, 结果表明, 当酸性品红浓度为20 mg/L和催化剂用量为0.2 g/L时, 反应120 min后染料脱色率可达到90%以上. 相似文献
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采用纳米硫化铅作为增感剂对边长为0.8μm的溴化银立方体颗粒进行了化学增感.利用微弱信号的微波吸收相敏检测技术,在超短脉冲激光作用下,获得了立方体溴化银乳剂中自由光电子和浅束缚光电子随增感时间变化的衰减曲线.通过测量溴化银光作用过程的时间分辨谱,讨论了卤化银晶体中电子陷阱对光电子运动行为的影响,分析了电子陷阱效应同增感时间之间的关系以及两个一级衰减区间寿命值同增感时间的关系.通过未增感样品与增感样品的衰减曲线对比,得到了在此实验条件下的最佳增感时间为60 min. 相似文献
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Zhao X Gorelikov I Musikhin S Cauchi S Sukhovatkin V Sargent EH Kumacheva E 《Langmuir : the ACS journal of surfaces and colloids》2005,21(3):1086-1090
Thiol-capped water-soluble PbS nanocrystals (NCs) stabilized with 1-thioglycerol, dithioglycerol, or a mixture of 1-thioglycerol/dithioglycerol (TGL/DTG) were prepared via one-stage synthesis at room temperature. We found that NCs stabilized with a TGL/DTG mixture show efficient and stable infrared photoluminescence centered in the second "biological window" (1050-1200 nm). Under optimized conditions, full width at half-maximum of the PL emission peak was from 70 to 100 nm. PbS NCs were stable to precipitation and aggregation for the time period from 2 to 3 months when stored in the dark under room temperature. Room-temperature photoluminescence quantum efficiency of NCs was from 7 to 10%. When NCs were stored at 37 degrees C, their PL emission red-shifted, consistent with the NC growth. 相似文献
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Jianjun Liu Kazushi Enomoto Kotaro Takeda Daishi Inoue Yong-Jin Pu 《Chemical science》2021,12(30):10354
The geometry in self-assembled superlattices of colloidal quantum dots (QDs) strongly affects their optoelectronic properties and is thus of critical importance for applications in optoelectronic devices. Here, we achieve the selective control of the geometry of colloidal quasi-spherical PbS QDs in highly-ordered two and three dimensional superlattices: Disordered, simple cubic (sc), and face-centered cubic (fcc). Gel permeation chromatography (GPC), not based on size-exclusion effects, is developed to quantitatively and continuously control the ligand coverage of PbS QDs. The obtained QDs can retain their high stability and photoluminescence on account of the chemically soft removal of the ligands by GPC. With increasing ligand coverage, the geometry of the self-assembled superlattices by solution-casting of the GPC-processed PbS QDs changed from disordered, sc to fcc because of the finely controlled ligand coverage and anisotropy on QD surfaces. Importantly, the highly-ordered sc supercrystal usually displays unique superfluorescence and is expected to show high charge transporting properties, but it has not yet been achieved for colloidal quasi-spherical QDs. It is firstly accessible by fine-tuning the QD ligand density using the GPC method here. This selective formation of different geometric superlattices based on GPC promises applications of such colloidal quasi-spherical QDs in high-performance optoelectronic devices.Gel permeation chromatography can finely control ligand coverage of PbS quantum dots. Self-assembly of these QDs with different ligand density leads to the formation of 2D square, hexagonal and 3D simple cubic and face-centered cubic superlattices. 相似文献
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Nyamen LD Rajasekhar Pullabhotla VS Nejo AA Ndifon PT Warner JH Revaprasadu N 《Dalton transactions (Cambridge, England : 2003)》2012,41(27):8297-8302
We report the synthesis of lead piperidine and lead tetrahydroquinoline dithiocarbamate (DTC) complexes and their use as single source precursors for the preparation of anisotropic PbS nanoparticles. The complexes were thermolysed in coordinating solvents such hexadecylamime (HDA), tri-n-octylphosphine oxide (TOPO), oleylamine (OA) and decylamine (DA) at various reaction temperatures. The variation of the reaction conditions and precursors produced PbS particles with shapes ranging from spheres to cubes and rods. The size of the particles is generally larger than those synthesized by conventional precursor routes. The electron microscopy and X-ray diffraction data confirm the particles to be very crystalline with the dominant cubic rock salt phase present in all samples. 相似文献
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PbS nanotubes were synthesized by the tiny water channels in bicontinuous microemulsions consisted of p-octyl polyethylene glycol phenylether (OP)/n-amyl alcohol/cyclohexane/water. The possible formation mechanism of PbS nanotubes is also discussed based on their shape evolutions. The results indicate that the formation of PbS nanotubes is probably via the process of the nucleation, growth, assemblage and crystallization. 相似文献
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Jiqing Jiao Xin Liu Wei Gao Chengwei Wang Huajie Feng Xiaolan Zhao Liuping Chen 《Solid State Sciences》2009,11(5):976-981
The cubic PbS nanoflowers were successfully synthesized by the biomolecule-assisted method in the presence of supercritical carbon dioxide. This is an effective, simple and green synthetic method for the preparation of nanomaterials. It is noteworthy that the dosage of cetyltrimethylammonium bromide (CTAB) and chitosan as well as appropriate reaction time and pressure of system are crucial to form the unusual nanoflower structured PbS. The unique nanoflowers have numerous petals, which grow along the 〈100〉 direction as a single crystal. Especially, the nanoflower PbS indicates better sensitivity to the laser power via Raman spectra. Although the product size of PbS obtained is larger than the Bohr radius, its UV–vis absorption spectrum shows a remarkable blue-shift from that of bulk PbS due to quantum-confinement effects. 相似文献
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PbS nanotubes were successfully synthesized in bicontinuous microemulsion system containing cyclohexane, aqueous solution,
n-pentanol and surfactant OP (polyethylene glycol p-octylphenyl ether). The morphology of PbS nanotubes was confirmed by the transmission electron microscopy. The crystallinity
and structural features of PbS nanotubes were characterized by powder X-ray diffraction. The effect of key parameters, such
as the molar ratio of water to surfactant and the reactant concentration, on the resulting product has also been investigated.
The formation mechanism of PbS nanotubes and nanowires synthesized in bicontinuous microemulsion system has been discussed. 相似文献