Salt-assisted Synthesis of Hollow Bi_2WO_6 Microspheres with Superior Photocatalytic Activity for NO Removal

Hollow Bi2WO6 microspheres are successfully synthesized by a facile ultrasonic spray pyrolysis（USP） method using NaCl as a salt template.The as-prepared hollow microspheres assembled as nanoplates with dimensions of approximately 41-148 nm and are dispersed with non-uniform pores on the template surface.By swapping the salt template with KC1 or Na2SO4,different morphologies of Bi2WO6 are obtained.The experimental results demonstrate that NaCl plays a key role on the formation of Bi2WO6 with hollow structures.The specific growth mechanism of hollow microspheres was studied in detail.The Bi2WO6 hollow microspheres exhibit an excellent photocatalytic efficiency for NO removal under solar light irradiation,which is 1.73 times higher than for the Bi2WO6 obtained in the absence of any salt template.This enhancement can be ascribed to the simultaneous improvement on the surface area and visible light-harvesting ability from the hollow structures.Electron spin resonance（ESR） results suggest that both radicals of ·OH and ·O2^- are involved in the photocatalytic process over the BWO-NaCl sample.The production of ·O2^- radicals offers better durability for NO removal.

基于SiO_(2)@CA微球的非晶结构色涂层的制备及光学性能

目的制备基于SiO_(2)@CA微球的非晶结构色涂层,并得到调控结构色颜色的方法,作为功能包装或智能包装的潜在应用。方法将咖啡酸(CA)与SiO_(2)微球在CuCl_(2)和NaBO_(3)·4H_(2)O的催化下产生活性氧(ROS),使CA迅速氧化为具有强黏附性的聚咖啡酸(PCA)包覆SiO_(2)微球,即SiO_(2)@CA复合微球,然后将该复合微球与无水乙醇组成的悬浮液喷涂于亲水化的玻璃基片表面,从而制得非晶结构色涂层。采用FT-IR、XPS、TGA、SEM等对SiO_(2)@CA复合微球及其结构色涂层进行表征,研究CA含量、CuCl_(2)/CA的质量比和NaBO_(3)·4H_(2)O/CA的质量比对复合微球的形貌及结构色涂层光学性能的影响。结果在CA质量分数为5%、CuCl_(2)/CA的质量比为12∶和NaBO_(3)·4H_(2)O/CA的质量比为64∶的制备条件下可以得到适宜的SiO_(2)@CA复合微球及结构色涂层。结论采用CA可有效提高所制备非晶结构色涂层颜色的对比度,实现颜色调控。

Battery Separators Functionalized with Edge-Rich MoS2/C Hollow Microspheres for the Uniform Deposition of Li2S in High-Performance Lithium-Sulfur Batteries

As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase conversion that occurs during the charge-discharge process,particularly the deposition of solid Li2S from the liquid-phase polysulfides,which greatly limits its practical application.In this paper,edge-rich MoS2/C hollow microspheres(Edg-MoS2/C HMs)were designed and used to functionalize separator for Li-S battery,resulting in the uniform deposition of Li2S.The microspheres were fabricated through the facile hydrothermal treatment of MoO3-aniline nanowires and a subsequent carbonization process.The obtained Edg-MoS2/C HMs have a strong chemical absorption capability and high density of Li2S binding sites,and exhibit excellent electrocatalytic performance and can effectively hinder the polysulfide shuttle effect and guide the uniform nucleation and growth of Li2S.Furthermore,we demonstrate that the Edg-MoS2/C HMs can effectively regulate the deposition of Li2S and significantly improve the reversibility of the phase conversion of the active sulfur species,especially at high sulfur loadings and high C-rates.As a result,a cell containing a separator functionalized with Edg-MoS2/C HMs exhibited an initial discharge capacity of 935 mAh g-1 at 1.0 C and maintained a capacity of 494 mAh g-1 after 1000 cycles with a sulfur loading of 1.7 mg cm-2.Impressively,at a high sulfur loading of 6.1 mg cm-2 and high rate of 0.5 C,the cell still delivered a high reversible discharge capacity of 478 mAh g-1 after 300 cycles.This work provides fresh insights into energy storage systems related to complex phase conversions.

SiO_(2)气凝胶及其他功能填料对反射隔热涂料性能影响

为了提高SiO_(2)气凝胶反射隔热涂料的保温隔热性能,研究了亲水、疏水性SiO_(2)气凝胶的掺量对反射隔热涂料的太阳热反射率和隔热温差的影响,以及几种功能性填料的作用。结果表明:掺量1.5%的疏水SiO_(2)气凝胶制得的反射隔热涂料性能最好,其太阳热反射率达到了83.32%,隔热温差达到了31.6℃。掺量为9%的空心玻璃微珠所制的反射隔热涂料的反射率达到85.33%,隔热温差达到32.65℃,是其他功能性填料中表现最佳的一种填料。1.5%疏水SiO_(2)气凝胶和9%空心玻璃微珠复配制得的反射隔热涂料其导热系数为0.041 W·m^(-1)·K^(-1),比各自单独使用制得的反射隔热涂料的导热系数低30%~40%,表现出良好的保温隔热效果。

Template-Free Synthesis of Sb_2S_3 Hollow Microspheres as Anode Materials for Lithium-Ion and Sodium-Ion Batteries

Hierarchical Sb_2S_3 hollow microspheres assembled by nanowires have been successfully synthesized by a simple and practical hydrothermal reaction. The possible formation process of this architecture was investigated by X-ray diffraction, focused-ion beam-scanning electron microscopy dual-beam system, and transmission electron microscopy. When used as the anode material for lithium-ion batteries, Sb_2S_3 hollow microspheres manifest excellent rate property and enhanced lithium-storage capability and can deliver a discharge capacity of 674 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. Even at a high currentdensity of 5000 m A g^(-1), a discharge capacity of541 m Ah g^(-1) is achieved. Sb_2S_3 hollow microspheres also display a prominent sodium-storage capacity and maintain a reversible discharge capacity of 384 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. The remarkable lithium/sodium-storage property may be attributed to the synergetic effect of its nanometer size and three-dimensional hierarchical architecture, and the outstanding stability property is attributed to the sufficient interior void space,which can buffer the volume expansion.

Step-scheme ZnO@ZnS hollow microspheres for improved photocatalytic H_(2) production performance

Constructing a step-scheme heterojunction at the interface between two semiconductors is an efficient way to optimize the redox ability and accelerate the charge carrier separation of a photocatalytic system for achieving high photocatalytic performance.In this study,we prepared a hierarchical ZnO@ZnS step-scheme photocatalyst by incorporating ZnS into the outer shell of hollow ZnO microspheres via a simple in situ sulfidation strategy.The ZnO@ZnS step-scheme photocatalysts had a large surface area,high light utilization capacity,and superior separation efficiency for photogenerated charge carriers.In addition,the material simulation revealed that the formation of the step-scheme heterojunction between ZnO and ZnS was due to the presence of the built-in electric field.Our study paves the way for design of high-performance photocatalysts for H_(2) production.

Robust,fluorine-free and superhydrophobic composite melamine sponge modified with dual silanized SiO_(2) microspheres for oil-water separation

Massive oily wastewater discharged from industrial production and human daily life have been an urgent environmental and ecological challenge.Superhydrophobic materials have attracted tremendous attention due to their unique properties and potential applications in the treatment of wastewater.In this study,a novel superhydrophobic/superoleophilic composite melamine sponge modified with dual silanized SiO_(2) microspheres was fabricated simply by a two-step sol-gel method using vinyltriethoxysilane and hexadecyltrimethoxysilane as functional agent,which exhibited a water contact angle of 153.2°and a water sliding contact angle of 4.8°.Furthermore,the composite sponge showed the excellent oil adsorption performance and the compressive elasticity reaching up to 130 g·g^(-1) of dichloromethane and 33.1 kPa of compressive stress.It was worth noting that the composite sponge presented the excellent separation efficiency(up to 99.5%)in the processes of continuous oil/water separation.The robust superhydrophobic composite melamine sponge provided the possibility with the practical application for oil-water separation.

Highly photoreactive TiO_2 hollow microspheres with super thermal stability for acetone oxidation

TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.

Facile Preparation of Al2O3 Hollow Microspheres Via a Urea-mediated Precipitation Process

Al2 O3 hollow microspheres without noticeable aggregation have been prepared via a facile templating route with urea-mediated precipitation. The precipitation process is different from the surfaceadsorption method which is confined to the adsorption capacity of the template surface. TEM and SEM images indicate that most of these Al2 O3 hollow microspheres with shell thickness of tens of nanometers and diameters in a narrow range of 100-200 nm consist of a shell of closely packed nanoparticles. The optimal amount of H2 O and EtOH are 40 and 120 m L, respectively. The specific surface area, average pore size and pore volume of the Al2 O3 hollow microspheres（calcinated at 600 ℃） are 328.52 m2/g, 17.496 nm and 1.985 cm3/g, respectively. As the calcination temperature increases from 600 to 1 100 ℃, the phase composition changes from γ-Al2 O3 to θ-Al2 O3 and a-Al2 O3, and the surface morphology appears to change from a relatively rough surface formed by nanoparticles to a smooth surface formed by lamellar, which lead to the closure of pore channels and the reduction of specific surface.

纳米SiO_(2)粒子表面接枝共聚合物微球的制备及其吸附Cu^(2+)性能

采用KH570对纳米SiO_(2)进行改性,将其作为Pickering乳液的稳定剂;利用反相(Pickering)乳液聚合法制备SiO_(2)@丙烯酰胺(AM)-丙烯酸(AA)共聚物复合微球,并对改性前后纳米SiO_(2)以及复合微球的结构、形貌及质量损失进行了表征;探究pH值、温度和单体比例对复合微球吸附Cu^(2+)效果影响,并对吸附过程进行动力学和吸附等温线拟合。结果表明,改性后的纳米SiO_(2)亲油性增强,提高稳定乳液的能力;Cu^(2+)吸附实验表明,复合微球吸附的最佳pH值为6,且吸附量随着AA用量增加而增大;复合微球吸附Cu^(2+)的过程符合准二级动力学模型和Langmuir模型。

纳米SiO_(2)微球的制备及其结构与性能研究

以十二烷基三甲基溴化铵(CTAB)为表面活性剂,氨水为催化剂,正硅酸乙酯(TEOS)为前驱体,采用工艺简单的氨催化水解法在乙醇/水混合溶剂中制备纳米SiO_(2)微球。利用扫描电镜(SEM)对样品的形貌和粒度进行了表征。结果表明,在其它条件不变的情况下,随着CTAB用量的增加,SiO_(2)微球粒径逐渐增大、粒度分布逐渐变宽;随着醇水比例的降低、TEOS用量及氨水浓度的增加,SiO_(2)微球粒径均先增大后减小;而随着醇水比例的降低,粒度分布先变宽后变窄;TEOS用量的增加,粒度分布先变窄后变宽;氨水浓度的增加,SiO_(2)微球的粒度分布逐渐变宽。制备SiO_(2)微球的最佳醇水比例为0.6∶1,所得微球分散性较好,粒度分布较窄,平均粒径为533 nm。并研究得出CTAB和乙醇在纯水体系中是通过“水包油”体系发生作用。所得微球成膜后的光学性能(透过率为76.06%;雾度为48.35%)满足实际应用,表明其在防眩增透显示屏领域具有潜在的应用价值。

SiO_(2)光子晶体的制备及其在增强上转换发光的应用

用改进的St?ber法制备了均一分散的SiO_(2)微球。探讨了不同温度环境和正硅酸乙酯(TEOS)的用量对生成微球粒径大小的影响。用扫描电子显微镜、分光光度计、X射线衍射仪紫外-近红外吸收发射光谱仪等仪器对粉末和薄膜的形貌与光学性能进行表征。结果表明:随着温度的增加,微球的粒径不断减小。TEOS试剂的用量增加,生成微球的粒径也随之增加。讨论了不同温度的自组装环境对光子晶体自组装的影响。结果表明,当自组装温度为55℃时制备的二氧化硅光子晶体薄膜质量最高。用980 nm激发光对旋涂在玻璃基板和光子晶体上的上转换薄膜进行发光测试,红光发光增强1.72倍,绿光发光增强1.93倍。这是由于带隙位于激发光波段的光子晶体表面具有高光子态密度,能够增强发光粒子周围电磁场强度,提高了电子跃迁的几率,从而增强了荧光强度。

Preparation and Properties of TiO2-Coated Hollow Glass Microspheres as Thermal Insulation Materials for Energy-Saving Buildings

A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter as nanoparticles with the formation of the SiO Ti bonds.The growth mechanism accounting for the formation of the TiO2 nanolayers was proposed.The morphology,composition,thermal insulation properties,and visible-near infrared(VIS-NIR)refl ectance of the HGMs/TiO2 composite hollow spheres were characterized.The VIS-NIR reflectance of the HGMs/TiO2 composite hollow spheres increased by more than 30%compared to raw HGMs.The thermal conductivity of the particles is 0.058 W/(m K).The result indicates that the VIS-NIR reflectance of the composite hollow spheres is strongly influenced by the coating of TiO2.The composite hollow spheres were used as the main functional filler to prepare the organic-inorganic composite coatings.The glass substrates coated by the organic-inorganic coatings had lower thermal conductivity and higher near infrared reflectivity.Therefore,the HGMs/TiO2 composite hollow spheres can reflect most of the solar energy and effectively keep out the heat as a thermal insulation coating for energy-saving constructions.

Monodisperse SiO_(2) Microspheres with Large Specific Surface Area: Preparation and Particle Size Control

Monodisperse SiO_(2) microspheres have found applications in catalysis,drug delivery,coatings,cosmetics,optical sensing and plastics.The particle size of monodisperse SiO_(2) microspheres is closely related to its application.In this paper,monodisperse SiO_(2) microspheres with tunable diameter were successfully synthesized using cetyltrimethylammonium bromide(CTAB)as template.The monodisperse SiO_(2) microspheres with diameters ranging from 200 nm to 3μm were obtained by controlling the concentration of CTAB,tetraethyl orthosilicate(TEOS),diethanolamine(DEA)and reaction temperature.The BET surface area could reach 835 m^(2)·g^(-1) and mean pore diameter was 2.3 nm.The formation mechanism of monodisperse SiO_(2) microspheres was investigated.

Preparation of Hollow Silica Microspheres via Poly（N-isopropylacrylamide）

Core-shell structured SiO2/poly（N-isopropylacrylamide） （SiO2/PNIPAM） microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl orthosilicate （TEOS） on the surface of PNIPAM template at 50 ~C. The PNIPAM template can be easily removed by water at room temperature so that SiO2 hollow microspheres were finally obtained. The transmission electron microscope and scanning electron microscope observations indicated that SiO2 hollow microspheres with an average diameter of 150 nm can be formed only if there are enough concentration of PNIPAM and TEOS, and the hy- drolysis time of TEOS. FTIR analysis showed that part of PNIPAM remained on the wall of SiO2 because of the strong interaction between PNIPAM and silica. This work provides a clean and efficient way to prepare hollow microspheres.

表面磷酸基修饰的巯基功能化空心介孔SiO_(2)的制备及吸附性能研究

在水溶液中,分别以乙烯基三乙氧基硅烷VTES为内核前驱体,2-氰乙基三乙氧基硅烷CTES为致孔剂,巯基丙基三甲氧基硅烷MPTMS为外壳前驱体,使用一步法结合官能团差异性刻蚀技术制备巯基功能化空心介孔SiO_(2)纳米球HS-HMSNs。并通过后磷酸化法将HS-HMSNs转化为磷酸修饰的杂化空心多孔SiO_(2)纳米球H_(2)O_(3)P-HMSNs。通过扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱、X射线光电子能谱仪等多种表征方法完整地揭示了功能化空心多孔材料的形貌、结构、化学组分和比表面积。结果表明:磷酸修饰后的材料含有一定量的P元素,且P含量为1.76%,证实了磷酸基团被接枝到SiO_(2)材料上,且磷酸修饰后的材料仍保持空心结构,并具有较大的比表面积。Cd^(2+)吸附实验显示,两种功能化材料在120min后吸附量接近饱和,当pH为6左右时,Cd^(2+)初始浓度维持在100~160mg/L时,材料表现出优良的吸附性能。此时,HS-HMSNs的最大吸附量达277.49mg/g,H_(2)O_(3)P-HMSNs的最大吸附量达304.62mg/g。且经过5次循环使用后,对Cd^(2+)的吸附性能仍是第1次的65%~70%,说明H_(2)O_(3)P-HMSNs作为重金属离子吸附剂具有良好的循环使用性能。

分级介孔SiO_(2)空心微球氨基修饰及木瓜蛋白酶固定化

为了提高SiO_(2)载体材料的酶固定化性能,分别采用接枝法和原位法对自制的分级介孔SiO_(2)空心微球进行氨基修饰,并考察其木瓜蛋白酶固定化性能。与未修饰的样品相比,接枝法修饰后微球一级最可几孔径(8.68~8.70 nm)减小,二级最可几孔径(29.30~29.89 nm)无明显变化,表明氨基主要修饰在一级孔道中。原位法修饰后样品的一级最可几孔径(4.47~7.34 nm)、二级最可几孔径(14.49~19.78 nm)均有明显减小,表明一、二级孔道中均有氨基修饰。与未修饰和接枝法修饰的样品相比,原位法修饰后样品的最大木瓜蛋白酶固定量为750 mg×g^(-1),相对酶活力为121.0%,均高于未修饰和接枝法修饰的样品。原位法氨基修饰在提高SiO_(2)载体材料的酶固定化性能方面更具优势。

Preparation and electrochemical performance of hollow-spherical polypyrrole/V_2O_5 composite

In order to improve the lower practical capacity and bad cyclability of crystalline V2O5（c-V2O5）,the vanadium oxide（V2O5） and polypyrrole（PPy） hybrid with hollow-spherical（HS） structure was studied.HS nanocomposite comprised of conductive polypyrrole and vanadium pentoxide（PPy/V2O5） was synthesized by polymerization of pyrrole monomer（Py） in the hollow-microspherical V2O5 host.This novel hybrid was characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and tested as the cathode material for lithium-ion batteries（LIB） by galvanostatic cell cycling and electrochemical impedance spectroscopy（EIS）.The hollow-spherical polypyrrole/vanadium oxide（HS-PPy/V2O5） composites,in which PPy molecules are intercalated between the layers of V2O5,exhibit slight reduced capacity and substantially improve cyclability and electrochemical activity compared with the pure HS-V2O5.

弱酸性溶液中快速制备PS/SiO_(2)空心微球及其应用研究

以聚乙烯吡咯烷酮为稳定剂,通过乳液聚合法合成了单分散聚苯乙烯(PS)微球。以PS微球为种子,在弱酸性溶液及不同温度下水解正硅酸乙酯(TEOS),一步合成了具有PS和SiO_(2)复合壳层的空心微球。研究了溶液p H及反应温度对微球空心度的影响,结果表明,能否得到空心微球受制于不同pH及温度下TEOS水解、缩聚速率以及所生成的纳米Si O_(2)对PS微球的包覆程度,溶液pH为3.0左右时,室温下反应就可以得到空心微球;pH升高至4.0~5.0时,反应温度达到40℃以上才可以得到空心微球;pH达到6.0时即使升温至50℃以上也无法得到空心微球。通过实验证实了空心SiO_(2)微球镀层不仅对玻璃具有增透效果,还可以使玻璃表面呈现出超亲水性。

纳米SiO_(2)微球@苯并三氮唑自修复型缓蚀剂的制备及表征

以正硅酸乙酯(TEOS)为硅源,采用乳液聚合的方式制备了表面负载介孔二氧化硅(SiO_(2))微球的苯并三氮唑(BTA)乳液。研究结果表明,当m(油相)∶m(水相)即m(石油醚+氨水+复合乳化剂)∶m(BTA+水)=4∶5、m(乳化剂)=4.5 g、t=80℃、t=8 h,乳液最稳定、性能最佳。通过SEM、FTIR、XRD等表征手段研究了介孔SiO_(2)微球的结构及形貌,表明纳米SiO_(2)成功负载于BTA表面,纳米粒子大小均一,分布均匀。