二氧化硅空心球的制备及研究

在乙醇/水的混合溶液中,采用聚乙烯吡咯烷酮（PVP）为分散剂,偶氮二异丁腈（AIBN）为引发剂,通过分散聚合法制备出聚苯乙烯（PS）微球。然后以微球为模板,PS粒子作为核,SiO_2作为壳,在600℃时经过热分解得到SiO_2空心球。通过热分析仪、扫描电子显微镜对制得的空心球进行了表征和分析,并讨论其影响因素。     

Carbonized thiourea formaldehyde resin blending polypyrrole hollow spheres composites with improved supercapacitor performances as electrodes

Thiourea formaldehyde resin has been condensation-polymerized in the polypyrrole hollow spheres suspension to obtain TF/PPy. Then, TF/PPy has been carbonized at 750 °C to acquire CTF/PPy composites. Scanning electron microscope and transmission electron microscope images were used to observe the morphology of the samples, TGA, XRD, Raman, XPS, and BET were used to analyze the structure of the materials. The results show PPy was blended with the TF resin, and the obtained CTF/PPy exhibited improved supercapacitive performances compared with CTF. The specific capacitance of CTF/PPy is 226.8 F g⁻¹ at the current density of 1 A g⁻¹ according to GCD curves, much higher than that of CTF. More interestingly, the cycling retention of CTF/PPy electrode at the current density of 10 A g⁻¹ is up to 120.2% after 10 000 cycles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47816.     

Hollow carbon spheres and their noble metal-free hybrids in catalysis

Hollow carbon spheres have garnered great interest owing to their high surface area, large surface-to-volume ratio and reduced transmission lengths. Herein, we overview hollow carbon sphere-based materials and their noble metal-free hybrids in catalysis. Firstly, we summarize the key fabrication techniques for various kinds of hollow carbon spheres, with a particular emphasis on controlling pore structure and surface morphology, and then heterogeneous doping as well as their metal-free/containing hybrids are presented; next, possible applications for non-noble metal/hollow carbon sphere hybrids in the area of energy-related catalysis, including oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, water splitting, rechargeable Zn-air batteries and pollutant degradation are discussed; finally, we introduce the various challenges and opportunities offered by hollow carbon spheres from the perspective of synthesis and catalysis.     

Submicron mullite hollow spheres synthesized via UV polymerization of Pickering emulsions

We here propose a simple, facile, and effective method to prepare submicron mullite hollow spheres templated from Pickering emulsions. Dual-phase sol consisted of boehmite and silica nanoparticles decorated by pentanoate ion could assemble at water/oil interface irreversibly to form photosensitive Pickering emulsions. The droplets of emulsions could be separated by dilution and formed by photopolymerization to gain hybrid microspheres, which could completely transform to mullite hollow microspheres via binder removal and sintering. It is found that the prepared hollow microspheres possess intact morphology, favorable sphericity, large cavity volume, and bulk density of 0.356 g/cm³. Importantly, the average diameter of mullite hollow spheres obtained via this method could be as low as 0.33–2.31 μm. This steady method is efficient and suitable for various types of inorganic particles, providing an innovative perspective for preparing fine hollow spheres applicable for filtration, drug loading as well as energy storage areas.     

Optical properties of colloidal crystalline arrays composed of hollow polystyrene spheres

We have evaluated the optical properties of close‐packed and non close‐packed colloidal crystalline arrays made of hollow polystyrene spheres. Close‐packed colloidal crystalline arrays were fabricated by simple evaporation of dispersions, whereas nonclose‐packed colloidal crystalline arrays were fabricated by exploiting electrostatic interactions between the spheres in aqueous dispersion. Optical properties of the arrays were estimated from angle‐resolved reflection spectra. The Bragg diffraction peak of the colloidal crystalline array made of hollow spheres was of shorter wavelength than in the case of solid spheres, not only for the close‐packed array but also for the nonclose‐packed array. These shifts were caused by a decrease in the effective refractive index n_eff with decreasing particle refractive index. We have found that this relationship could be explained by the simple equation n_eff = n_particle?+ n_solvent (1 ? ?), where ? is the volume fraction of the particles, for both close‐packed and non close‐packed arrays. The current work suggests new possibilities for the creation of advanced colloidal crystals. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2364–2368, 2007     

Template synthesis of composite hollow spheres using sulfonated polystyrene hollow spheres

In this paper, we propose a general template synthesis approach towards composite hollow spheres using sulfonated polystyrene gel hollow spheres. The gel hollow spheres are highly crosslinked to well preserve the spherical contour during template synthesis. It is important that the gel shell is infiltrative to many species to allow their further growth therein by specific interaction. The grown materials are well distributed thorough the whole shell forming composite shells. This method is general, which is proved by the growth of many representative materials for example metal Pd nanoparticles, magnetite Fe₃O₄ nanocrystallites, conducting polyaniline, and inorganic titania and silica. It is found that mesoporous inorganic shells are obtained after the template gel is calcined. This concept can be applied to other gel shells and grown materials expecting a new family of composite hollow spheres.     

Nanostructured hollow spheres of hydroxyapatite: preparation and potential application in drug delivery

A solvothermal method has been successfully used to prepare nanostructured hydroxyapatite (HA) hollow spheres with average diameters of about 500 nm and shell thicknesses of about 100 nm in a glycerin/water mixed solvent. Transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FESEM) images show that the shells of the HA hollow spheres are actually composed of nanosheets with thicknesses of about 10 nm. By tuning the glycerin/water volume ratio, two other kinds of HA solid spheres with average diameters of about 6 or 20 μm were assembled from nanoflakes. The properties of the different kinds of spheres as drug delivery carriers were evaluated. Ibuprofen (IBU) was chosen as the model drug to load into the HA samples. The nanostructured HA samples showed a slow and sustained release of IBU. The HA hollow spheres exhibited a higher drug loading capacity and more favorable release properties than the HA solid spheres and thus are very promising for controlled drug release applications.     

Effect of sintering temperature on the characteristics of ceramic hollow spheres produced by sacrificial template technique

Ceramic hollow spheres were produced by a sacrificial template technique with subsequent sintering under temperatures ranging from 1100 °C to 1250 °C. The effect of the sintering temperature on the structure of the ceramic hollow spheres was investigated by optical and scanning electron microscopy, and a gas adsorption method. The results show that the structure of the ceramic hollow spheres can be controlled, with the retention of the hollow spherical shape, by variation of the sintering temperature. Increase of the sintering temperature from 1100 °C to 1250 °C decreased the outer diameter of the ceramic hollow spheres by 14 percent, the shell thickness by 18 percent, and the void area ratio of the shell surface by 9.2 times; both of the specific surface area and the total pore volume of ceramic hollow spheres decreased by 60 percent.     

过渡金属化合物多壳空心球的制备及其应用研究进展

过渡金属化合物多壳空心球密度低、比表面积大,同时具有较高的光俘获效率,相对于传统的简单中空结构材料在应用中具有更显著的优势,其形状、大小、组成和壳层数可控的中空结构具有独特的性能优势。本文主要介绍了过渡金属化合物多壳空心球的不同制备方法,如硬模板法、软模板法和无模板法;概述了不同反应条件对过渡金属化合物形貌的影响;总结了其应用在锂电池、染料敏化太阳能电池、超级电容器和传感器等领域时表现出的优异性能;并对过渡金属化合物多壳空心球的可控合成进行了前景展望。     

中空活性碳纤维概述

中空活性碳纤维以其独特的结构而具有比活性炭和活性碳纤维更优异的性能，本文概述了中空活性碳纤维的制备过程及其应用，并指出，其作为吸附储氢材料具有一定前景。     

Synthesis of composite eccentric double-shelled hollow spheres

Eccentric double-shelled hollow polyethylacrylate (PEA)/polystyrene (PS) crosslinked composite spheres were synthesized by phase separation during swelling polymerization of their mother polymer hollow spheres. The group -NH₂ was introduced within the network by ammonization of PEA. Other materials for example silica could be favorably grown within the gel network by a sol-gel process. The polymer/silica hollow spheres gave the corresponding derivative hollow spheres with varied composition including SiO₂/carbon, carbon and β-SiC, with the eccentric double-shelled morphology retained.     

Template method synthesis of mesoporous carbon spheres and its applications as supercapacitors

Mesoporous carbon spheres (MCS) have been fabricated from structured mesoporous silica sphere using chemical vapor deposition (CVD) with ethylene as a carbon feedstock. The mesoporous carbon spheres have a high specific surface area of 666.8 m²/g and good electrochemical properties. The mechanism of formation mesoporous carbon spheres (carbon spheres) is investigated. The important thing is a surfactant hexadecyl trimethyl ammonium bromide (CTAB), which accelerates the process of carbon deposition. An additional advantage of this surfactant is an increase the yield of product. These mesoporous carbon spheres, which have good electrochemical properties is suitable for supercapacitors.     

Inward template synthesis of intact hollow spheres

A facile and general one-step approach is presented to synthesize hollow spheres with varied composition by an aerosol-assisted solvent evaporation process. The monomer of ethyl-2-cyanoacrylatemide contained in the aerosol droplets can form an outer shell by a fast polymerization around the droplets. Materials inside the droplets further grow inwardly against onto the interior surface of the first shell forming another shell forming composite hollow spheres. The hollow spheres are derived by dissolution of the outer shell, therefore the intact shell can be well preserved. Many approaches can be exploited forming the second shell for example sol-gel process of oligomers and phase separation from polymer solutions. Microstructure of the hollow spheres can be tuned from smooth to porous. The methodology is general.     

环氧乙烷与CO2合成碳酸乙烯酯动力学研究

环氧乙烷与CO2合成法是一种具有工业应用价值的碳酸乙烯酯生产方法,有必要对其反应机理和动力学加以研究。文中假设CO2与环氧乙烷合成碳酸乙烯酯的反应按照亲核加成反应机理分3步进行,其中催化剂溴化四乙铵作为亲核试剂。在一定温度和一定的压力下,碳酸乙烯酯的合成反应速率正比于催化剂和环氧乙烷浓度。提出了动力学方程,通过实验对假设机理进行了验证,并回归得到动力学方程参数。所得合成碳酸乙烯酯的反应动力学方程对大规模工业化生产具有一定参考价值。     

聚丙烯腈基中空炭膜的研究发展

概述了聚丙烯腈基活性炭纤维的制备和结构,制备条件对聚丙烯腈基中空纤维炭膜的影响,以及聚丙烯腈基中空纤维炭膜作为医用吸附剂的可行性。     

A simple one‐step chemical route to gold/polymer core/shell composites and polymer hollow spheres

Au/poly(o‐toluidine) (POT) core/shell composite spheres have been successfully fabricated by chemical polymerization route in aqueous solution without the aid of surfactant or functional acids using HAuCl₄ as the oxidant. By altering the concentration of oxidant, the amount of Au nanoparticles inside each POT sphere can be tuned from tens to one. Moreover, uniform POT hollow spheres with one opening in each polymer surface can be obtained under extremely low concentration of oxidant. The chemical structures of Au/POT composites were confirmed by Fourier transform infrared (FTIR), UV‐vis, and X‐ray diffraction (XRD) spectroscopies. Moreover, the formation mechanisms of Au/POT core/shell composites and POT hollow spheres were also discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Nano-sized cobalt oxide/mesoporous carbon sphere composites as negative electrode material for lithium-ion batteries

A new type of nano-sized cobalt oxide compounded with mesoporous carbon spheres (MCS) as negative electrode material for lithium-ion batteries was synthesized. The composite containing about 20 wt.% cobalt oxide exhibits a reversible capacity of 703 mAh/g at a constant current density of 70 mA/g between 0.01 and 3.0 V (vs. Li⁺/Li), and remains a capacity retention of 77% after the 30th cycle. The improvement could be attributed to that the MCS had a good electronic conductivity and severed as dispersing medium to prevent cobalt oxide nanoparticles from aggregating, and the mesopores (cobalt oxide not fully occupied) can provide the enough space to buffer the volume change during the Li-ion insertion and extraction reactions in cobalt oxide nanoparticles.     

中空纳米碳颗粒的制备方法及应用前景

综述了中空结构纳米碳颗粒的几种制备新方法、优缺点和在电催化剂中的应用现状,展望了这种新型碳结构在催化领域的应用前景。