纳米尺度电极材料的模板法合成及其电化学性能研究(英文)

本文利用氧化铝模板法合成了不同纳米尺寸的LiMn2 O4 纳米管 /纳米线及碳纳米管 .采用原子力显微镜 (AFM )及高分辨透射电镜 (TEM )表征了相关的模板及纳米管 .同时也报道了以纳米管阵列的LiMn2 O4 电极的循环伏安法的初步研究结果     

Wrapping and inclusion of organic molecules with ultrathin,amorphous metal oxide films

In this review, we overview metal oxide nanostructures in which organic molecules play important roles as templates, as structural units, and, in some cases, as hosts. Their structural precision and diversity are discussed from the viewpoint of the topology of a metal-oxygen network. Supramolecular capsules of metal oxides are prepared by the self-assembly of polyoxometalates. Zeolites and mesoporous materials are synthesized by using organic molecules with their assemblies acting as templates. The topological networking of silsesquioxanes makes it possible to produce novel nanocomposites and microporous materials. In the final section, we demonstrate our recent studies into molecular imprinting, the encapsulation of a fluorescent dye, and the wrapping of individual polymer chains. Ultrathin, amorphous metal oxide films can retain the shape of organic molecules and can be used to create molecular composites by precisely wrapping individual molecules. These films are also effective in insulating molecular functions from external environments. The advantages of amorphous metal oxides are discussed in relation to the properties of the corresponding crystalline metal oxides and their potential prospects in nanotechnology.     

Preparation of MnO2 Loaded Hydrothermal Carbon-coated Electrospun PAN Fiber Membranes for Highly Efficient Adsorption and Separation of Cationic Dye

Hydrothermal carbonaceous materials and MnO₂ have been proved to be promising adsorbents to remove organic dyes from wastewater. In this study, flexible MnO₂ loaded hydrothermal carbon-coated electrospun poly-acrylonitrile(AC/MnO₂/PAN) fiber membranes were fabricated by a facile one-step hydrothermal method and activated by NaOH solution. The composite fibers exhibited large adsorption capacity toward cationic dyes and excellent mechanical properties. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption for methylene blue(MB), methyl violet(MV) and malachite green(MG) are 1173.27,1106.31 and 1129.89 mg/g, respectively, according to Langmuir fitting. The AC/MnO₂/PAN fiber membrane also showed satisfactory performances for selective adsorption and recyclability. In addition, based on selective adsorption, the AC/MnO₂/PAN fiber membranes that are repulsive to the anionic dye methyl orange(MO) can separate the MB/MO mixture solution by dynamic filtration. Thus, this work not only provides a facile strategy to fabricate large capacity adsorbents, but also demonstrates the potential applications in the dye wastewater treatment field.     

原位自组装形成二氧化硅/十六烷基三甲基溴化铵纳米网络粒子

提出了以具有纳米尺寸孔径及孔壁厚度的MCM 48作为无机基体、以无机 有机原位自组装的方法形成纳米网络粒子 .研究结果表明 ,在一定实验条件下 ,有机相可进入无机相的三维孔道自组装形成立方有序结构的纳米网络复合粒子 .通过研究纳米网络粒子在极性介质和非极性介质中的分散发现 ,有机相的存在有利于纳米网络粒子的分散     

Microtubular Self‐Assembly of Covalent Organic Frameworks

Despite significant progress in the synthesis of covalent organic frameworks (COFs), reports on the precise construction of template‐free nano‐ and microstructures of such materials have been rare. In the quest for dye‐containing porous materials, a novel conjugated framework DPP‐TAPP‐COF with an enhanced absorption capability up to λ=800 nm has been synthesized by utilizing reversible imine condensations between 5,10,15,20‐tetrakis(4‐aminophenyl)porphyrin ( TAPP ) and a diketopyrrolopyrrole ( DPP ) dialdehyde derivative. Surprisingly, the obtained COF exhibited spontaneous aggregation into hollow microtubular assemblies with outer and inner tube diameters of around 300 and 90 nm, respectively. A detailed mechanistic investigation revealed the time‐dependent transformation of initial sheet‐like agglomerates into the tubular microstructures.     

Recent advances on hydrogels based on chitosan and alginate for the adsorption of dyes and metal ions from water

In contemporary times, water resources have become increasingly scarce and suffer from anthropogenic pollution sources with an organic and inorganic origin that are products of industrial, agricultural, and everyday waste. Contamination with heavy metals and dyes in wastewater is considered a risk for water sources that can leak into underground and surface sources, leading to increased biological and chemical contamination. The pollutant removal process is performed by adsorption treatment methods, which is the most common method, and it is considered an effective method with a high and economical removal rate.In this review, we discuss the use of biobased hydrogel adsorbents in the removal of organic dyes and metal ions from water. The literature indicates that hydrogels exhibit rapid absorption kinetics and a dye removal absorption capacity that can reach more than 100 mg/g and sometimes more than 2000 mg/g, with a metal adsorption capacity ranging from 38 mg/g to more than 440 mg/g. These results are discussed and compared by taking into account hydrogel materials that contain biopolymers such as alginate, chitosan or both. In general, absorption depends mainly on biobased materials, which have a natural origin and can be utilized to synthesize hydrogels to remove pollutants, dyes and heavy metals. Chitosan and alginate are prominent materials for this use and they can be incorporated with other components to obtain hydrogels or nanocomposite materials with different efficacies to remove dyes and metal ions.     

Porous magnetic manganese oxide nanostructures: synthesis and their application in water treatment

Magnetic manganese oxide nanostructures are fabricated at room temperature by mixing a KMnO(4) solution and oleic acid capped Fe(3)O(4) particles. Oleic acid molecules capped Fe(3)O(4) particles are oxidized by potassium permanganate (KMnO(4)) in an aqueous solution to produce porous magnetic manganese oxide nanostructures. The synthesis technique can be extended to other MnO(x) structures with composition of different nanocrystals, such as quantum dots, noble metal crystals which may have important applications as catalysts, adsorbents, electrodes and advanced materials in many scientific disciplines. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption measurements are employed to characterize the structures. As an adsorbent in water treatment, the nanostructures possess a large adsorption capability and high organic pollutant removal rates due to the large surface area and pore volume. The nanostructures are recyclable as their adsorption capability can be recovered by combustion. Furthermore, the strong magnetism exhibited by the structures provides an easy and efficient separation means in wastewater treatment under an external magnetic field.     

Self‐Assembly of Metal–Organic Frameworks into Monolithic Materials with Highly Controlled Trimodal Pore Structures

We present a two‐step template‐free approach toward monolithic materials with controlled trimodal porous structures with macro‐, meso‐, and micropores. Our method relies on two ordering processes in discrete length scales: 1) Spontaneous formation of macroporous structures in monolithic materials by the sol–gel process through the short‐range ordered self‐assembly of metal–organic frameworks (MOFs), and 2) reorganization of the framework structures in a mediator solution. The Zr‐terephthalate‐based MOF (UiO‐66‐NH₂) was adopted as a proof of concept. The self‐assembly‐induced phase separation process offered interconnected macropores with diameters ranging from 0.9 to 1.8 μm. The subsequent reorganization process converted the microporous structure from low crystalline framework to crystalline UiO‐66. The resultant mesopore size within the skeletons was controlled in the range from 9 to 21 nm. This approach provides a novel way of designing spaces from nano‐ to micrometer scale in network‐forming materials.     

Templated Synthesis of Nitrogen‐Enriched Nanoporous Carbon Materials from Porogenic Organic Precursors Prepared by ATRP

A facile templated synthesis of functional nanocarbon materials with well‐defined spherical mesopores is developed using all‐organic porogenic precursors comprised of hairy nanoparticles with nitrogen‐rich polyacrylonitrile shells grafted from sacrificial cross‐linked poly(methyl methacrylate) cores (xPMMA‐g‐PAN). Such shape‐persistent all‐organic nanostructured precursors, prepared using atom transfer radical polymerization (ATRP), assure robust formation of template nanostructures with continuous PAN precursor matrix over wide range of compositions, and allow for removal of the sacrificial template through simple thermal decomposition. Carbon materials prepared using this method combine nitrogen enrichment with hierarchical nanostructure comprised of microporous carbon matrix interspersed with mesopores originating from sacrificial xPMMA cores, and thus perform well as CO₂ adsorbents and as supercapacitor electrodes.     

Study of adsorption properties of synthesized mesoporous silica doped with dysprosium and modified with nickel

Mesoporous silica (MPS) modified with nickel and MPS doped with dysprosium and modified with nickel have been synthesized by the template method. The adsorbents are characterized by various techniques such as transmission electron microscopy, scanning electron microscopy, X-ray diffraction, inductively coupled plasma spectroscopy, and X-ray fluorescence analyses. The adsorption properties of the synthesized samples have been investigated by inverse gas chromatography. Furthermore, thermodynamic characteristics of the adsorption of test compound belonging to different classes of organic compounds were obtained. In addition, the contributions of the energy of specific interactions to the total adsorption energy were calculated. It is also shown that entropy plays the determining role in the adsorption of test compounds on synthesized mesoporous materials.     

新颖表面结构的脲醛树脂-聚丙烯酰胺复合微球的制备研究

将高分子微凝胶模板法应用于制备脲醛树脂[Urea-formaldehyde resin (UF Resin)]-聚丙烯酰胺[Polyacrylamide (PAM)]有机-有机复合微球材料. 以PAM高分子微凝胶为模板, 通过控制甲醛和尿素的缩聚反应在反相悬浮体系中进行, 制备得到了具有新颖表面形貌的脲醛树脂-聚丙烯酰胺[UF Resin/PAM]有机-有机复合微球, 利用扫描电子显微镜(SEM)、热重分析(TGA)、红外(FT-IR)等手段对复合微球进行了表征. 实验结果表明, 复合微球的表面形貌与甲醛和尿素溶液的pH值、甲醛和尿素溶液的浓度、甲醛和尿素的摩尔比、模板的组成等因素有关. 可以预期, 本研究方法将为制备具有特异表面形貌的有机-有机复合微球材料提供了一条有效的途径.     

Simple fabrication of a phosphorus-doped hierarchical porous carbon via soft-template method for efficient CO2capture

Hierarchical porous carbons are widely used as adsorbents, catalyst supports, electrode materials, and other applications because of their high specific surface area (SSA), varied pore structure, adjustable porosity, and excellent physicochemical stability. Introducing heteroatoms such as N, P, or S, with electronegativities different from that of carbon, into the carbon skeleton can change the chemical properties of the surface and the density of the electron cloud around the carbon matrix, thus altering interactions of CO₂molecules with the surface and improving CO₂adsorption capacity. Therefore, doping heteroatoms in carbon materials has attracted a great amount of attention. In this paper, the template method was used with F108 (polyethylene glycol–polypropylene glycolpolyethylene glycol) as the template, resorcinol and formaldehyde solutions as the carbon sources, phosphoric acid as the phosphorus source, and KOH as the activator to prepare phosphorus-doped hierarchical porous carbons. Through a series of characterization and CO₂adsorption experiments, the influence of the amount of KOH and template agent on the pore structure of carbon materials was studied. We conclude that these phosphorus-doped hierarchical porous carbon materials are promising CO₂adsorbents.     

Tailoring the Optical Absorption of Water‐Stable ZrIV‐ and HfIV‐Based Metal–Organic Framework Photocatalysts

New Zr^IV‐ and Hf^IV‐based metal–organic framework photocatalysts, termed VNU‐1 and VNU‐2 (where VNU=Vietnam National University), were synthesized and their resulting structures fully characterized. By employing a highly π‐conjugated linker, namely 1,4‐bis(2‐[4‐carboxyphenyl]ethynyl)benzene, the optical absorption properties were effectively red‐shifted into the visible light region. This strategy, coupled with the high water stability of the materials, led to enhanced MOF‐driven photocatalytic degradation, under ultraviolet‐visible light, of organic dye pollutants commonly found in wastewater.     

湿式氧化用于染料废水脱色:过去20年回顾（英文）简

Wet air oxidation (WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures (125-320℃) and pressures (0.5-20 MPa) using gaseous oxygen (or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.     

Metal–Organic Frameworks: From Molecules/Metal Ions to Crystals to Superstructures

Metal–organic frameworks (MOFs) are among the most attractive porous materials known today, exhibiting very high surface areas, tuneable pore sizes and shapes, adjustable surface functionality, and flexible structures. Advances in the formation of MOF crystals, and in their subsequent assembly into more complex and/or composite superstructures, should expand the scope of these materials in many applications (e.g., drug delivery, chemical sensors, selective reactors and removal devices, etc.) and facilitate their integration onto surfaces and into devices. This Concept article aims to showcase recently developed synthetic strategies to control the one‐, two‐ and three‐dimensional (1‐, 2‐ and 3D) organisation of MOF crystals.     

Self‐Templated Stepwise Synthesis of Monodispersed Nanoscale Metalated Covalent Organic Polymers for In Vivo Bioimaging and Photothermal Therapy

Size‐ and shape‐controlled growth of nanoscale microporous organic polymers (MOPs) is a big challenge scientists are confronted with; meanwhile, rendering these materials for in vivo biomedical applications is still scarce. In this study, a monodispersed nanometalated covalent organic polymer (MCOP, M=Fe, Gd) with sizes around 120 nm was prepared by a self‐templated two‐step solution‐phase synthesis method. The metal ions (Fe³⁺, Gd³⁺) played important roles in generating a small particle size and in the functionalization of the products during the reaction with p ‐phenylenediamine (Pa). The resultant Fe‐Pa complex was used as a template for the subsequent formation of MCOP following the Schiff base reaction with 1,3,5‐triformylphloroglucinol (Tp). A high tumor suppression efficiency for this Pa‐based COP is reported for the first time. This study demonstrates the potential use of MCOP as a photothermal agent for photothermal therapy (PTT) and also provides an alternative route to fabricate nano‐sized MCOPs.     

Oxalic acid cross-linked sodium alginate and carboxymethyl chitosan hydrogel membrane for separation of dye/NaCl at high NaCl concentration

Dye desalination is a challenge in the treatment of textile wastewater with high salt concentration. It is imperative to develop salt resistance membrane that is from sustainable materials to effectively treat dye/salt mixtures. And most polymer membrane materials are non-renewable petrochemical resources.In this paper, a green hydrogel membrane(CMCS-OA-Na Alg) was prepared by non-metallic ions of oxalic acid(OA) cross-linking of two natural macromolecules of sodium alginate(Na Alg) and carboxym...     

一步制备高比表面积介孔Co3O4-CeO2及其表征

以有序介孔二氧化硅KIT-6为硬模板,硝酸钴、硝酸铈为金属源,分别在真空辅助条件和普通搅拌条件下制备了介孔CoCeOx复合氧化物。采用XRD、SEM、TEM、N2吸脱附等技术表征了复合氧化物的物化性质,并评价其氧化甲苯的性能。结果表明,在真空辅助和搅拌条件下制备的CoCeOx氧化物是由Co3O4和CeO2组成的介孔Co3O4-CeO2复合氧化物,其比表面积分别为141和89 m^2·g^-1,平均孔径分别为8.7和9.6 nm。真空辅助纳米复制过程有利于金属盐的前驱体充分填充到模板的孔隙中,去除模板后,可以得到有序的介孔复合金属氧化物。所制备介孔钴铈复合氧化物具有孔道有序性好、比表面积大的特点,在挥发性有机化合物的氧化去除方面具有一定的应用前景。     

General and Facile Syntheses of Metal Silicate Porous Hollow Nanostructures

Porous hollow nanostructures have attracted intensive interest owing to their unique structure and promising applications in various fields. A facile hydrothermal synthesis has been developed to prepare porous hollow nanostructures of silicate materials through a sacrificial‐templating process. The key factors, such as the concentration of the free metal cation and the alkalinity of the solution, are discussed. Porous hollow nanostructures of magnesium silicate, nickel silicate, and iron silicate have been successfully prepared by using SiO₂ spheres as the template, as well as a silicon source. Several yolk–shell structures have also been fabricated by a similar process that uses silica‐coated composite particles as a template. As‐prepared mesoporous magnesium silicate hollow spheres showed an excellent ability to remove Pb²⁺ ions in water treatment owing to their large specific surface and unique structures.     

多孔碳材料的模板法制备、活化处理及储能应用

简要介绍了广义模板法制备多孔碳材料的研究现状,并进一步阐述了应用传统活化法对模板法制备的多孔碳材料进行结构调控. 最后,详细介绍了多孔碳材料在氢气吸附以及超级电容器用电极材料等储能领域的应用.