Interfacially formed organized planar inorganic, polymeric and composite nanostructures

This paper discusses synthetic strategies for fabrication of new organized planar inorganic, polymeric, composite and bio-inorganic nanostructures by methods based on chemical reactions and physical interactions at the gas-liquid interface, Langmuir monolayer technique, interfacial ligand exchange and substitution reactions, self-assembling and self-organization processes, DNA templating and scaffolding. Stable reproducible planar assemblies of ligand-stabilized molecular nanoclusters containing definite number of atoms have been formed on solid substrate surfaces via preparation and deposition of mixed Langmuir monolayers composed by nanocluster and surfactant molecules. A novel approach to synthesis of inorganic nanoparticles and to formation of self-organized planar inorganic nanostructures has been introduced. In that approach, nanoparticles and nanostructures are fabricated via decomposition of insoluble metal-organic precursor compounds in a layer at the gas-liquid interface. The ultimately thin and anisotropic dynamic monomolecular reaction system was realized in that approach with quasi-two-dimensional growth and organization of nanoparticles and nanostructures in the plain of Langmuir monolayer. Photochemical and redox reactions were used to initiate processes of interfacial nucleation and growth of inorganic phase. It has been demonstrated that morphology of resulting inorganic nanostructures can be controlled efficiently by variations of growth conditions via changes in state and composition of interfacial planar reaction media, and by variations of composition of adjacent bulk phases. Planar arrays and chains of iron oxide and ultrasmall noble metal (Au and Pd) nanoparticles, nanowires and new organized planar disk, ring, net-like, labyrinth and very high-surface area nanostructures were obtained by methods based on that approach. Highly organized monomolecular polymeric films on solid substrates were obtained via deposition of Langmuir monolayer formed by water-insoluble amphiphilic polycation molecules. Corresponding nanoscale-ordered planar polymeric nanocomposite films with incorporated ligand-stabilized molecular metallic nanoclusters and interfacially grown nanoparticles were fabricated successfully. Novel planar DNA complexes with amphiphilic polycation monolayer were formed at the gas-aqueous phase interface and then deposited on solid substrates. Toroidal and new net-like conformations were discovered in those complexes. Nanoscale supramolecular organization of the complexes was dependent on cationic amphiphile monolayer state during the DNA binding. These monolayer and multilayer DNA/amphiphilic polycation complex Langmuir-Blodgett films were used as templates and nanoreactors for generation of inorganic nanostructures via metal cation binding with DNA and following inorganic phase growth reactions. As a result, ultrathin polymeric nanocomposite films with integrated DNA building blocks and organized inorganic semiconductor (CdS) and iron oxide quasi-linear nanostructures were formed. It has been demonstrated that interaction of deposited planar DNA/amphiphilic polycation complexes with bulk phase colloid inorganic cationic ligands (CdSe nano-rods) can result in formation of new highly organized hybrid bio-inorganic nanostructures via interfacial ligand exchange and self-organization processes. The methods developed can be useful for investigation of fundamental mechanisms of nanoscale structural organization and transformation processes in various inorganic and molecular systems including bio-molecular and bio-inorganic nanostructures. Also, those methods are relatively simple, environmentally safe and thus could prove to be efficient practical instruments of molecular nanotechnology with potential of design and cost-effective fabrication of new controlled-morphology organized planar inorganic and composite nanostructured materials. Possible applications of obtained nanostructures and future developments are also discussed.     

Controllable Synthesis and Optical Properties of Connected Zinc Oxide Nanoparticles

Connected zinc oxide (ZnO) nanoparticles are successfully synthesized by a simple solution‐based chemical route that uses evaporation and concentration technology. The influences of processing parameters, especially the evaporation and concentration time on the size and morphology of the nanoparticles, have been investigated by transmission electron microscopy (TEM) and high‐resolution TEM (HRTEM). The structure and optical properties are systematically characterized by X‐ray diffraction (XRD), UV/Vis spectrophotometery, and fluorescence spectroscopy (FL). It is found that the average diameter and morphology are strongly affected by the evaporation and concentration time. Additionally, the formation mechanism of the nanoparticles is also discussed. The studies revealed that the evaporation and concentration are important aggregation or nucleation processes for ZnO growth, which leads to the macro‐differences in morphology. These results provide some insight into the growth mechanism of ZnO nanostructures. The synthetic strategy developed in this study may also be extended to the preparation of other nanomaterials and promising applications in various fields of nanotechnology.     

Exploring the Interaction between Graphene Derivatives and Metal Ions as a Key Step towards Graphene–Inorganic Nanohybrids

The assembly of graphene derivatives and inorganic nanostructures opens up an exciting new field in the functionalization of nanomaterials. However, a better understanding of the interaction between graphene derivatives and inorganic precursors remains a challenge. This work provides an efficient strategy for exploring this interaction by first modifying graphene oxide with aniline, glycine, and glycyl glycine, respectively, and thus engineering the chemical microenvironments on graphene sheets for anchoring metal ions. After that, the affinities of graphene derivatives to various metal ions can be investigated with the help of a conventional electrochemical method. The method highlights the importance of graphene chemistry in hybrid preparation and provides design principles for chemical modifiers used in the construction of multifunctional carbon–inorganic nanostructures.     

Emerging Strategies for the Total Synthesis of Inorganic Nanostructures

New synthetic innovations are rapidly being developed to address the demand for complex, next‐generation nanomaterials with rigorously controlled architectures and interfaces. This Review highlights key strategies for the chemical transformation and stepwise synthesis of multicomponent inorganic nanostructures, with the existing nanoscale transformations categorized into classes of reactions that are related to those used in the synthesis of organic molecules. The application of concepts used in molecular synthesis—including site‐selectivity, regio‐ and chemoselectivity, orthogonal reactivity, coupling reactions, protection/deprotection strategies, and procedures for separation and purification—to nanoscale systems is emphasized. Collectively, the resulting synthetic concept represents an emerging model for the synthesis of complex inorganic nanostructures on the basis of the guiding principles that underpin the multistep total synthesis of complex organic molecules and natural products.     

Crystal structures, anisotropic growth, and optical properties: controlled synthesis of lanthanide orthophosphate one-dimensional nanomaterials

The fundamental understanding of the relationship between crystal structure and the dynamic processes of anisotropic growth on the nanoscale, and exploration of the key factors governing the evolution of physical properties in functional nanomaterials, have become two of the most urgent and challenging issues in the fabrication and exploitation of functional nanomaterials with designed properties and the development of nanoscale devices. Herein, we show how structural and kinetic factors govern the tendency for anisotropic growth of such materials under hydrothermal conditions, and how the crystal structure and morphology influence the optical properties of Ln3+-doped nanocrystals. The synthesis of phase-pure and single-crystalline monoclinic, hexagonal, and tetragonal one-dimensional LnPO4 nanostructures of different aspect ratios by means of kinetically controlled hydrothermal growth processes is demonstrated. It is shown that the tendency for anisotropic growth under hydrothermal conditions can be enhanced simply by modifying the chemical potentials of species in the reaction solution through the use of carefully selected chelating ligands. A systematic study of the photoluminescence of various Eu3+-doped lanthanide phosphates has revealed that the optical properties of these nanophosphors are strongly dependent on their crystal structures and morphologies.     

Asymmetric Hybrid Polyoxometalates: A Platform for Multifunctional Redox‐Active Nanomaterials

Access to asymmetrically functionalized polyoxometalates is a grand challenge as it could lead to new molecular nanomaterials with multiple or modular functionality. Now, a simple one‐pot synthetic approach to the isolation of an asymmetrically functionalized organic–inorganic hybrid Wells–Dawson polyoxometalate in good yield is presented. The cluster bears two organophosphonate moieties with contrasting physical properties: a chelating metal‐binding group, and a long aliphatic chain that facilitates solvent‐dependent self‐assembly into soft nanostructures. The orthogonal properties of the modular system are effectively demonstrated by controlled assembly of POM‐based redox‐active nanoparticles. This simple, high‐yielding synthetic method is a promising new approach to the preparation of multi‐functional hybrid metal oxide clusters, supermolecular systems, and soft‐nanomaterials.     

Effects of quenching on the morphology and crystal structure of ZnO nanostructures

Zinc oxide nanostructures were prepared by a simple wet chemical procedure using zinc acetate and sodium hydroxide as precursors. The process was subjected to quenching treatment and the effect of the treatment on the formation of the nanostructures was studied using atomic force and scanning electron microscopies. The change in crystal structure of the nanostructures due to quenching was studied using an X-ray diffractometry that established that physical and structural properties of the nanostructures were largely influenced by the quenching treatment.     

无机纳米晶的形貌调控及生长机理研究

形貌及尺寸规整可控的纳米晶体的合成是目前十分引人注目的纳米材料研究领域．制备合成中的形貌调控及其功能化是这些纳米材料能够得到应用的关键问题．研究者们希望在纳米晶的任一阶段均能实现控制并在期望的阶段停止,从而得到尺寸、形态、结构及组成确定的纳米晶体．本文综述了近年来无机纳米晶体的典型合成路径,深入探讨了纳米晶在成核、生长及熟化阶段的控制原理,研究了液相合成纳米材料过程中晶体结构与生长行为的相关性问题,并总结了几类具有代表性的低维、多维纳米晶体的形成规律和生长机理．探索纳米粒子的调控合成对于纳米材料的规模化生产及应用具有重要的理论价值和指导意义．     

Effects of organic ligands, electrostatic and magnetic interactions in formation of colloidal and interfacial inorganic nanostructures

This paper discusses effects of organic ligands, electrostatic and magnetic interactions involved in morphological control of chemically synthesized inorganic nanostructures including colloid and planar systems. The special attention was concentrated on noble metal (gold and palladium) nanoparticles and nanostructures formed at the gas-liquid interface. The analysis of experimental data showed that electrostatic and ligand-related interactions influence very strongly on the metal nanostructure morphology. The hydrophobicity of ligand, charge and binding affinity to inorganic phase are important factors influencing the morphology of inorganic nanostructures formed in a layer at the gas/liquid interface by the interfacial synthesis method. The important point of this method is the quasi two-dimensional character of reaction area and possibilities to realize ultimately thin and anisotropic dynamic monomolecular reaction system with two-dimensional diffusion and interactions of precursors, intermediates and ligands resulting in planar growth and organization of inorganic nanoparticles and nanostructures in the plain of Langmuir monolayer. The morphology of resulting inorganic nanostructures can be controlled efficiently by variations of growth conditions via changes in state and composition of interfacial planar reaction media with the same precursor, and by variations of composition of adjacent bulk phases. The extreme anisotropy and heterogeneity of two-dimensional interfacial reaction system allows creating conditions when growing inorganic particles floating on the aqueous phase surface interact selectively with hydrophobic water-insoluble ligands in interfacial monolayer or with hydrophilic bulk-phase ligands, or at the same time with ligands of different nature present in monolayer and in aqueous phase. The spatial anisotropy of interfacial reaction system and non-homogeneity of ligand binding to inorganic phase gives possibilities for growth of integrated anisotropic nanostructures with unique morphologies, in particularly those characterized by very high surface/volume ratio, high effective perimeter, and labyrinth-like structure. In a case of magnetic nanoparticles dispersed in colloids specific magnetic dipolar interactions can result in formation of chains, rings and more complex nanoparticulate structures or separated highly anisotropic nanoparticles. Theoretical considerations indicate to the importance of system dimensionality in relation to the energy balance which determines specific features of structure organization in planar charged metallic and magnetic nanostructures. For example, a requirement of Coulomb energy minimum, the possibility of free electron redistribution and strengthened attractive interactions between particles in metallic nanostructures can explain formation of very branchy systems with extremely high "effective perimeter". The obtained experimental and literature data show that system dimensionality, organic ligand nature along with electrostatic and magnetic interactions are most important factors of morphological control of chemically synthesized inorganic nanomaterials. The understanding and appropriate exploitation of these factors can be useful for further developments of efficient nanofabrication techniques based on colloidal and interfacial synthetic methods.     

模板法制备无机纳米材料的研究进展

模板法在无机纳米材料的制备过程中能够有效地控制形貌、粒径和结构,已成为合成无机纳米材料的前沿方法。综述了模板法制备无机纳米材料的研究进展,主要介绍了硬模板剂(多孔阳极氧化铝、介孔碳)和软模板剂(高分子聚合物、生物高分子)的制备及其应用,结合模板法的作用机制,重点论述了不同种类的模板剂在无机纳米材料制备过程中对于形貌的影响。并对模板法制备无机纳米材料的前景和现存问题进行了总结。参考文献35篇。     

特殊纳米结构的化学自组装

本文介绍了近年来国际上一维纳米材料的制备方法的最近进展，如模板法、激光剥蚀法、分子束外延法、有机溶剂中溶液-液体-固体生长法等，同时还介绍了利用新的化学自组装路线制备一维核／鞘结构、无机半导体／高分子纳米电线、金属硫化物纳米空球和花生状纳米结构等工作。     

Facile solution route to vertically aligned, selective growth of ZnO nanostructure arrays

For any future cost-effective applications of inorganic nanostructures, in particular, hybrid photovoltaic cells, it is essential that these inorganic nanomaterials be solution processable and selectively printable. This letter reports the selective growth of single-crystal ZnO nanostructures based on the microcontact printing of an inorganic nanocrystal seeding film. The pattern-transfer quality is dependent on the concentration of the inking solution. Variable yet controllable anisotropic growth of ZnO nanowires has been demonstrated on the transferred patterns of ZnO nanocrystal films. The patterning and growth of these highly ordered arrays of ZnO nanostructures employ a simple soft lithography technique and mild reaction conditions at low temperature and in the absence of harmful organic additives.     

Micro-extraction of Xenobiotics and Biomolecules from Different Matrices on Nanostructures

Sample preparation is the backbone of any analytical procedure; it involves extraction and pre-concentration of the desired analytes; often at trace levels. The present article describes the applications of nanomaterials (carbon-based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro-extraction, and dispersive liquid phase micro-extraction in the analyses of aqueous samples. The nanoparticles used for micro-extractions are discussed on the basis of their chemical natures. The synthetic route and the preparation of nanomaterials are described along with the optimization strategies for micro-extraction. A comparison between the conventional materials and nanomaterials for micro-extraction is proposed. The key roles of the nanomaterials for the micro-extraction of different analytes such as drugs, pesticides, polycyclic aromatic hydrocarbons, proteins and peptides from aqueous samples are reported. The use of nanomaterials, combined with miniaturized micro-extraction techniques, proved to be highly promising for sample preparation of various matrices with analytes at trace levels.     

表面展示肽在无机纳米材料的合成与组装中的应用

本文综述了表面展示肽在无机纳米材料合成与组装中的应用.表面展示肽是利用噬菌体、细胞等表面展示技术筛选出来的一类多肽,可以特异性地识别不同的无机物表面.一方面它们能够诱导不同种类无机纳米材料的合成,有助于我们进一步认识生物矿化的过程和基本原理;同时表面展示肽也可以用于无机纳米材料的组装,构建具有特定功能的纳米结构,从而为纳米器件的构造提供新的途径.     

分级纳米材料的结构、制备及其应用

纳米材料因其独特的表面效应、体积效应和量子效应等特点,在化工、生物工程、医学和能源等领域有着广阔的应用。 由简单的低维纳米结构作为主要的构建单元并按照特定的排列方式组装成规整有序的三维结构,即分级纳米结构,已经开展了许多的研究。 本文综述了分级纳米结构的制备方法和微观结构,及其在污水处理、超级电容器、太阳能电池以及光催化等领域的应用。     

Solution-phase synthesis of inorganic nanostructures by chemical transformation from reactive templates

The solution-phase synthesis by chemical transformation from reactive templates has proved to be very effective in morphology-controlled synthesis of inorganic nanostructures. This review paper summarizes the recent progress in solution-phase synthesis of one-dimensional and hollow inorganic nanostructures via reactive templates, focusing on the approaches developed in our lab. The formation mechanisms based on reactive templates are discussed in depth to show the general concepts for the preparation proces...     

能源催化材料的电化学合成

电催化是发展可持续洁净能源技术的基础科学,是电化学能源转换和物质转化的关键环节.精准合成催化活性纳米结构是制约很多电催化反应走向实际应用的重要挑战.与湿化学合成、固相合成和气相沉积等传统方法相比,电化学合成是一种简单、快速、廉价及可控的高效催化材料制备方法,也是一种最为直接的一体化电极制备方法.本文综述了近年来利用电化学合成方法制备高效能源催化材料的研究进展.首先,简要介绍了电沉积、阴极腐蚀、电化学去合金化、电化学置换、电化学剥离和电化学修饰等几种主要电化学合成方法的基本原理,并讨论了电化学合成中电势、电流和电解质组成等关键合成参数的影响.然后,重点讨论了电化学合成的催化材料在燃料电池、电解水、二氧化碳/一氧化碳电还原、电化学合成氨、有机分子电化学转化等重要电催化反应中的应用.这些催化材料按照形貌可分为单原子催化剂、球形纳米粒子、形貌可控的纳米粒子、二维层状/片状纳米材料和三维纳米结构等.电化学合成在制备结构明确的单原子催化剂上具有其它合成方法不可比拟的优势.与胶体化学方法相比,电化学合成的尺寸和形貌可控的纳米粒子具有表面清洁、无表面附着的有机配体以及不需要焙烧等催化剂预处理的特点.除形貌外,电化学合成还可以制备在原子尺度上具有特定几何和电子结构的催化活性纳米结构.电化学方法也是催化剂修饰和再生的一种重要途径,结合特定的电化学程序,可在连续操作条件下实现催化材料的原位再生.通过讨论代表性的催化剂案例,分析这些催化剂在电催化应用中的构效关系,阐明了电化学合成方法在催化剂理性设计和制备中的独特优势.最后,总结了当前电化学合成催化材料方面存在的问题和研究挑战,并展望了未来的发展方向.电化学合成的能源催化材料在热催化、光催化等领域的应用价值仍需进一步探索.此外,电化学合成在金属有机框架、高熵合金等新兴功能材料的制备上也具有很好的应用前景.如何利用电化学的特点并结合原位表征、大数据预测等先进实验和理论方法,更加精准、可控地合成催化活性纳米结构依然是未来该领域重要的研究机遇.     

Preparation of Bi<Subscript>2</Subscript>WO<Subscript>6</Subscript> by Electrospinning: Researching Their Synthesis Mechanism and Photocatalytic Activity

The novel Bi₂WO₆ nanomaterials, which consist of nanosheets and nanoparticles, were successfully synthesized by a combination of electrospinning and calcining processes. The Bi₂WO₆ with different morphologies and microstructures had been obtained in the same experimental conditions. The growth mechanism of such special nanostructures was investigated, and citric acid played an important role in the formation of Bi₂WO₆ nanostructures. The Bi₂WO₆ nanomaterials exhibited excellent photocatalytic property in the photodegradation of the pulping and papermaking wastewater under visible light irradiation. Besides, preparation of the photocatalyst using electrospinning was beneficial for separation and recycling. So, the Bi₂WO₆ nanomaterials have a great potential in application for wastewater treatment in the future.     

阳极氧化铝模板限域制备一维杂化纳米材料及其多样化应用的研究进展

一维杂化纳米材料以其独特的物理化学性质,在电学、光学、催化等领域得到了广泛的应用。 其制备方法对一维杂化纳米材料性能的改变和调控显得至关重要。 模板法作为一种简单而普适的合成工艺,近几年来被广泛应用于纳米结构和纳米阵列的合成。 本文主要介绍了阳极氧化铝(AAO)模板法制备一维杂化纳米材料整体情况、AAO模板结合其他技术材制备材料的方法、一维杂化纳米材料在刺激响应性器件、能量存储与转换器件、催化等众多领域的应用。