Ordered porous diamond films fabricated by colloidal crystal templating

We have developed a colloidal crystal templating method for preparation of diamond films with 2D and 3D ordered porous structures. The technological process involved breaks down into (a) impregnation into the pores of silica colloidal crystal (opal) films of detonation nanodiamond (DND) particles from their hydrosol; (b) microwave plasma-enhanced chemical vapor deposition (MWPECVD) regrowth with diamond of pores with high DND filling; (c) Ar(+) ion dry etching of fragments of shells of coalesced diamond crystallites which form in the course of MWPECVD on the surface of the SiO(2) beads making up the outer surface of a film and (d) wet etching of the SiO(2) template in aqueous HF solution. The final samples are either connected to the substrate or free-standing films of various thicknesses having 2D or 3D ordered porous structures. The morphology of the diamond films fabricated by this method replicates the pore network of the opal template. Raman measurements confirm the diamond structure of the synthesized ordered porous material.     

Niobium and hafnium grown on porous membranes

In this work we report on a method for fabricating highly ordered nanostructures of niobium and hafnium metals by physical vapour deposition using two different templates: anodized aluminum oxide membranes (AAO) and zirconium onto AAO membranes (Zr/AAO). The growth mechanism of these metal nanostructures is clearly different depending on the material used as a template. A different morphology was obtained by using AAO or Zr/AAO templates: when the metal is deposited onto AAO membranes, nanospheres with ordered hexagonal regularity are obtained; however, when the metal is deposited onto a Zr/AAO template, highly ordered nanocones are formed. The experimental approach described in this work is simple and suitable for synthesizing nanospheres or nanoholes of niobium and hafnium metals in a highly ordered structure.     

Nickel nanoparticles decoration of ordered mesoporous silica thin films for carbon nanotubes growth

We report in situ successive depositions of nickel nanoparticles and carbon nanotubes (CNTs) on ordered mesoporous silica films used as template for the catalyst particles. The mesoporous films are synthesized by the evaporation-induced self-assembly process from tetraethyl orthosilicate derived oligomers and a di-block copolymer from dip-coating deposition method. The substrates are decorated with Ni nanoparticles through Ion Beam Deposition and posterior annealing to induce metal coalescence in the mesoporous cavities. CNTs were then grown by Chemical Vapor Deposition in the presence of an electric field. These techniques provide a simple control method producing ordered arrangements of catalyst nanoparticles and ordered nanostructures for large area applications.     

多孔氧化铝模板合成有序纳米结构材料的研究进展

模板法制备纳米结构是20世纪90年代中期发展起来的一种靠自组装构筑纳米结构的新工艺,在有序纳米结构的合成中有着广泛的应用.从多孔氧化铝模板独特的纳米孔结构出发,讨论了近年来该模板在纳米点、纳米线、纳米管、纳米异质节等纳米结构合成中的具体方法及应用,并展望了其发展前景.     

Colloidal templating for producing hollow ZnO shells: Fabrication, growth and electrical properties

Colloidal templating and pulsed laser deposition (PLD) have been combined to fabricate arrays of ordered two-dimensional hollow ZnO shells. Templates were formed by spin-coating colloidal solutions containing monodispersed polymethylmethacrylate (PMMA) beads. The optimum condition for forming templates of ordered two-dimensional geometry was deduced by calculating the radial distribution functions. On templates ZnO films were deposited by a PLD method. Upon annealing ZnO films crystallize into a würtzite structure. The surface morphology of hollow ZnO shells consists of protruding columnar nano-crystallites with no distinct ZnO texture. The electrical properties were measured as a function of annealing temperature. The electrical conductivity increases with increase in annealing temperature. The activation energy was estimated to be 0.7 eV. The change in the electrical properties upon grain growth has been attributed to alteration in the fraction site availability for defect formation at the grain boundaries.     

Template synthesis of highly ordered hydroxyapatite nanowire arrays

Highly ordered hydroxyapatite (HA) nanowire arrays were synthesized using porous anodic aluminum oxide (AAO) template from sol-gel solution containing P₂O₅ and Ca(NO₃)₂. Theresults of transmission electron microscopy (TEM) and scanning electron microscopy(SEM) revealed that the obtained HA nanowires had a uniform length and diameter andformed highly ordered arrays, which were determined by the pore diameter and thethickness of the applied AAO template. The results of X-ray diffraction (XRD) and X-rayphotoelectron spectroscopy (XPS) demonstrated that the major component was HA. Theselected-area electron diffraction (SAED) results indicated that HA was a polycrystallinestructure. This novel method of preparing highly ordered HA nanowires with a large areamight be important for many applications in biomaterials.     

Silver nanowires prepared by modified AAO template method

Thin film containing highly ordered silver nanowires array was prepared by using anodic aluminum oxide (AAO) template method. The morphology of the silver nanowires was confirmed by scanning electron micrograph (SEM). The result of the SEM showed that the silver nanowires were substantive, parallel, and ordered in the AAO template. Diameter distribution of the silver nanowires indicated that the average diameter was about 35 nm. The composition and structure of the Ag nanowires were investigated by Energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) pattern, respectively.     

C18TAB为模板剂合成有序多孔掺锡氧化锆

以C18TAB为模板剂,氧氯化锆和四氯化锡为原料,采用共沉淀法成功合成了不同掺锡量的有序多孔氧化锆.通过XRD、N2吸-脱附、FT-IR等技术表征材料的孔结构.结果表明,掺锡氧化锆孔排布为六方有序,材料的热稳定性、比表面积均高,与C16TAB为模板剂合成的结果相比,d100值、孔容明显增大,S(5)Zd100增大了0.22 nm.     

Designed Formation of Double-Shelled Ni–Fe Layered-Double-Hydroxide Nanocages for Efficient Oxygen Evolution Reaction

Delicate design of nanostructures for oxygen-evolution electrocatalysts is an important strategy for accelerating the reaction kinetics of water splitting. In this work, Ni–Fe layered-double-hydroxide (LDH) nanocages with tunable shells are synthesized via a facile one-pot self-templating method. The number of shells can be precisely controlled by regulating the template etching at the interface. Benefiting from the double-shelled structure with large electroactive surface area and optimized chemical composition, the hierarchical Ni–Fe LDH nanocages exhibit appealing electrocatalytic activity for the oxygen evolution reaction in alkaline electrolyte. Particularly, double-shelled Ni–Fe LDH nanocages can achieve a current density of 20 mA cm⁻² at a low overpotential of 246 mV with excellent stability.     

Preparation of polyaniline nanotubes array based on anodic aluminum oxide template

In this article, the highly ordered polyaniline (PANI) nanotubes array was prepared by in situ polymerization using anodic aluminum oxide (AAO) as template. Polymerization of aniline was confined in the one-dimensional nanochannel of AAO template. The aniline was adsorbed and polymerized preferentially on the pore walls of template. The structure of PANI nanotubes array was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), selected area electron diffraction (SAED) and dynamic force microscope (DFM). The results show that PANI nanotubes are synthesized successfully in the nanopores of template, the diameter and length of PANI nanotubes are closed to the pore diameter and thickness of AAO template, respectively, the arrangement of PANI nanotubes is very regular and uniform, the crystal form of PANI nanotubes is hexagonal, different from pseudo-orthorhombic crystal form of PANI bulk sample, and cell parameters a and b are 0.5008 nm. The change of crystal form is due to the confinement of AAO template, which makes the molecular chain of PANI arrange more ordered.     

Decasils,a new order-disorder family of microporous silicas

Decasils are a new order-disorder family of porous structures. All ordered and disordered decasil structures are built from one-dimensional chain-like basic building units that can be connected in different ways. Three simplest ordered framework structures of this family are possible: decasil types A, B, and C. All decasil types possess cage-like voids that share 8MR pore openings to give a one-dimensional channel system. Using two different templates an ordered and a disordered form of the decasil family of structures have been synthesized. RUB-3 (decasil type A) was obtained with exo-2-aminobicyclo[2.2.1.]heptan as template and is ordered; RUB-4 was obtained with 3-azabicyclo[3.2.2]nonane as template and is disordered. The structure of RUB-3, which crystallizes in space group C 2/m (a = 14.039(2)Å, b = 13.602(2) Å, c = 7.428(1) Å, and β = 102.22(3)°), has been solved by model building and simulation of X-ray powder pattern and has been confirmed in a Rietveld analysis.     

无机有序多孔材料研究进展

无机有序多孔材料因其独特性质而成为近年来材料研究的热点.综述了目前较为常见的几种无机有序多孔材料体系及其制备方法,比较了各种方法的优缺点,发现模板合成法、溶胶-凝胶法、水热合成法和阳极氧化法是常用的制备方法,微波辐射法、醇解法、化学气相沉积法和电泳沉积法等制备方法也得到越来越多的研究和应用.最后展望了无机有序多孔材料的发展趋势.     

Fabrication of hydroxyapatite with highly ordered macroporous frame by colloidal templating method

Three-dimensional, highly ordered macroporous frame of hydroxyapatite has been fabricated via a template-assisted colloidal processing technique. In the present method, colloidal template was first prepared with SiO₂ spheres by gravitational sedimentation, which was then infiltrated with hydroxyapatite precursor prepared by the sol-gel process. The resulting hydroxyapatite replicated the three-dimensionally ordered macroporous structure of SiO₂ template. Modified by H₂O₂, the SiO₂ spheres could be packed into better ordered templates. After removal of the template by immersing in NaOH solution, the well-ordered macroporous frame made from HA was obtained. The arrangement of the pore structure was hexagonal close-packed and pore sizes could be controlled by changing the sizes of SiO₂ spheres. The resulting highly ordered macroporous frame of hydroxyapatite could have potential applications in the biomedical field.     

Highly ordered uniform single-crystal Bi nanowires: fabrication and characterization

A mechanical pressure injection technique has been used to fabricate uniform bismuth (Bi) nanowires in the pores of an anodic aluminum oxide (AAO) template. The AAO template was prepared from general purity aluminum by a two-step anodization followed by heat treatment to achieve highly ordered nanochannels. The nanowires were then fabricated by an injection technique whereby the molten Bi was injected into the AAO template using a hydraulic pressure method. The Bi nanowires prepared by this method were found to be dense and continuous with uniform diameter throughout the length. Electron diffraction experiments using the transmission electron microscope on cross-sectional and free-standing longitudinal Bi nanowires showed that the majority of the individual nanowires were single crystalline, with preferred orientation of growth along the [011] zone axis of the pseudo-cubic structure. The work presented here provides an inexpensive and effective way of fabricating highly ordered single-crystalline Bi nanowires, with uniform size distributions.     

四方排列有序Ag/TiO2空心微球的制备及光催化性能

采用低温垂直沉积法制备了聚苯乙烯(PS)胶体模板,由于低温下粒子热运动受到抑制,排列时发生位错,因此模板中存在大面积四方排列结构。然后采用化学镀法、溶胶-凝胶法在PS微球表面依次沉积银纳米粒子、纳米TiO2,最后高温煅烧除去模板制备了四方排列有序Ag/TiO2空心微球。通过扫描电镜(SEM)、X射线衍射(XRD)对样品进行表征。结果表明这种材料很好地保持了模板的四方排列,具有高度有序的纳米结构。选择降解甲基橙溶液来检验样品的光催化性能,并与纳米TiO2薄膜、四方排列TiO2空心微球的光催化性能进行比较,结果表明四方排列Ag/TiO2空心微球具有最佳的光催化性能。这是有序空心纳米结构和银纳米粒子的沉积共同作用的结果。     

Synthesis of Hierarchical 4H/fcc Ru Nanotubes for Highly Efficient Hydrogen Evolution in Alkaline Media

Hierarchical metal nanostructures containing 1D nanobuilding blocks have stimulated great interest due to their abundant active sites for catalysis. Herein, hierarchical 4H/face‐centered cubic (fcc) Ru nanotubes (NTs) are synthesized by a hard template‐mediated method, in which 4H/fcc Au nanowires (NWs) serve as sacrificial templates which are then etched by copper ions (Cu²⁺) in dimethylformamide. The obtained hierarchical 4H/fcc Ru NTs contain ultrathin Ru shells (5–9 atomic layers) and tiny Ru nanorods with length of 4.2 ± 1.1 nm and diameter of 2.2 ± 0.5 nm vertically decorated on the surface of Ru shells. As an electrocatalyst for the hydrogen evolution reaction in alkaline media, the hierarchical 4H/fcc Ru NTs exhibit excellent electrocatalytic performance, which is better than 4H/fcc Au‐Ru NWs, commercial Pt/C, Ru/C, and most of the reported electrocatalysts.     

乳液聚合制聚苯乙烯纳米薄膜的分子链状态

以阴离子表面活性剂十二烷基硫酸钠SDS(C12H25O4SNa)与电解质调节剂氯化钾(KCl)在水相体系中形成的层状胶束为模板,以苯乙烯(C8H8)为单体,过硫酸铵((NH4)2S2O8)为引发剂,采用乳液聚合的方式,制备得到聚苯乙烯纳米薄膜。通过采用差示扫描量热法(DSC)以及在特殊温度下淬冷后再进行的X射线衍射分析法(XRD)检测,对聚苯乙烯纳米薄膜的分子链状态进行了研究。结果表明,聚苯乙烯纳米薄膜具有一种新颖的分子链状态,它可以在适当的温度下形成有序结构。     

有序纳米结构体系的模板合成法

利用具有特定结构的物质作为模板,来引导纳米有序结构的制备与组装,从而实现对纳米材料的组成、结构、形貌、尺寸、取向和排布等的控制,为研究纳米有序体系的性质提供了有利途径.模板可以分为软模板和硬模板两种,本文介绍了氧化铝、胶体晶体、胶束、生物大分子等几种常见模板的特点.利用模板法,可以制备金属、合金、氧化物、半导体和聚合物及其复合组份等多种纳米结构有序体系.本文结合我实验室最近的研究工作综述了利用模板法制备纳米有序结构体系的研究进展.     

Multilevel Hierarchically Ordered Artificial Biomineral

Living organisms are known for creating complex organic–inorganic hybrid materials such as bone, teeth, and shells, which possess outstanding functions as compared to their simple mineral forms. This has inspired many attempts to mimic such structures, but has yielded few practical advances. In this study, a multilevel hierarchically ordered artificial biomineral (a composite of hydroxyapatite and gelatine) with favorable nanomechanical properties is reported. A typical optimized HAp/gelatin hybrid material in the perpendicular direction of the HAp c‐axis has a modulus of 25.91 + 1.78 GPa and hardness of 0.90 + 0.10 GPa, which well matches that of human cortical bone (modulus 24.3 + 1.4 GPa, hardness 0.69 + 0.05 GPa). The bottom‐up crystal constructions (from nano‐ to micro‐ to macroscale) of this material are achieved through a hard template approach by the phase transformation from DCP to HAp. The structural biomimetic material shows another way to mimic the complex hierarchical designs of sclerous tissues which have potential value for application in hard tissue engineering.     

A simple method of preparing ordered and three-dimensionally-interconnected macroporous carbon with mesoporosity by using silica template

A simple and cost-effective method for the production of porous macro–meso structures is proposed. The approach involves using of monodispersed silica particles and in situ polymerized silica network as a removable template, and using resorcinol-sucrose derivative polymer as a carbon source. The three steps – carbon precursor, silica particles, template – are synthesized simultaneously through sol–gel reaction in one-pot system. The sample prepared by this method was characterized by scanning electron microscopy (SEM) and nitrogen adsorption and desorption, and the results present us a well long-ranged ordered structure and three-dimensionally interconnected macroporous carbon with mesoporosity.