中空微球及其制备方法

科技资讯科技资讯S I N &T NOLOGY I NFORM TI O N2008N O .11SC I ENC E &TEC HN OLO GY I NFO RM ATI O N高新技术聚合物中空微球内部的空腔，可以直接封装气体或小分子物质，如水、烃类等挥发性溶剂，以及其他具有特殊功能的化合物[1]。

由于空气/聚合物界面处的折光指数的差异和中空结构的特殊性能，因而可用作优质的聚合物系遮盖性颜料、抗紫外填料和手感改性剂等。

鉴于聚合物中空微球的用途广泛，引起了人们越来越多的关注，并对其制备方法和工艺条件的研究也日益深入。

1W /O /W 乳液聚合法W/O /W 乳液聚合法制备中空结构聚合物微球的主要过程包括先通过强剪切如超声分散制成W /O 乳液，再将此乳液在搅拌作用下缓慢滴加入溶有第二乳化剂的水溶液中，从而制得W/O /W 乳液，并经聚合反应制得聚合物乳胶微球内包含有水相的水系乳液，然后将该乳液加以干燥后即可得到中空结构的聚合物微球。

P a r k 等[2]用W /O/W 法制备了封装有不同疏水性物质的微胶囊，如卵清蛋白/聚氨醋囊。

Hi l de br a nd 等[3]报道了W /O 型乳液聚合法结合诱导相分离技术制备封装有缩氨酸和蛋白质的微胶囊。

2封装非溶剂乳液聚合法M c Dnoal d 等[4,5]报道了通过封装烃类非溶剂乳液聚合法制得0.2um ～1um 粘度的中空P S t /P M M A 微球的方法，微球孔隙率可达50%。

Ti ar ks 和L andf es t er [6-8]采用直接将单体和非溶剂烃混合，然后在水溶液中应用超声乳化成微乳液，接着以自由基引发聚合使生成的聚合物不溶于非溶剂烃而在其表面成壳，反应一步完成，最后去除非溶剂烃后得到纳米级聚合物中空微球。

研究表明，聚合物乳液的形态由乳化剂的类型、单体的极性以及所选用的非溶剂烃决定。

由于该法对过程操作要求较高，体系容易失稳，目前尚未达到实际应用的程度。

基于柯肯达尔效应的空心球制备摘要：介孔空心结构纳米材料与实心纳米颗粒相比具有更低的密度、更大的比表面积、更多元的功能调节维度(光、电、热、磁等)和更灵活的应用方式。

故有非常广泛的使用空间，而空心球制备方法有很多，本文结合传输原理传质部分内容以及柯肯达尔效应进行原理分析，应用举例以及改进方法等方面阐述。

关键词：空心球柯肯达尔效应扩散1空心材料优点介孔空心结构纳米材料与实心纳米颗粒相比具有更低的密度、更大的比表面积、更多元的功能调节维度(光、电、热、磁等)和更灵活的应用方式。

如：中空结构的微/纳米催化剂可以有效增加其在催化反应中的活性位点数；通过改变微/纳米介孔空心结构的组分、形貌、尺寸、壳壁厚度、孔隙率、孔的位置和孔内壁的特性等因素可以实现对其光、热、电、磁和催化等物化性能的调节；将难溶的功能活性成分担载在介孔空心的微/纳米结构的孔隙中，可以提高难溶物质的溶解度；将特异性药物担载在介孔空心微/纳米结构的孔隙中，为药物的缓释和可控释放提供了可能；将介孔空心微/纳米结构作为“纳米反应器”利用其量子限域效应和特殊的反应微环境，能得到特殊的反应结果。

因此，具有介孔空心结构的纳米粒子为纳米材料的功能化提供了广阔的空间。

2扩散及柯肯达尔效应简介空位机制适用于置换式固溶体的扩散"在置换式固溶体(或纯金属)中，由于原子的尺寸相差不大，因此很难进行间隙扩散"晶体中结点并非完全被原子所占据，存在一定的空位"而且空位的数量随温度的升高而增加，在一定的温度下对应着一定的空位浓度"也就是说在一定的温度下存在一定浓度空位的晶体才是稳定的"依靠空位的移动而进行的扩散机制称为空位扩散机制"其扩散过程是这样进行的，与空位相邻原子，由于热振动而可能脱离原来位置而到空位中去，占据了点阵中的空位，而原来原子所处位置就成为空位"这种过程不断进行，就发生了扩散"在空位扩散时，扩散原子跳入空位，此时所需的能量不大，但每次跳动必须有空位移动与之配合，即原子进入相邻空位实现一次跳动之后，必须等到一个新的空位移动到它的邻位，才能实现第二次跳动"因此实现空位扩散，必须同时具备两个条件：(l)扩散原子近旁存在空位；(2)近邻空位的扩散原子具有可以超过能垒的自由能石可见，空位扩散机制的扩散主要是通过空位的迁移来实现扩散，它的扩散激活能由原子跳动激活能与空位形成能两部分组成"柯肯达尔效应最初是金属学中的概念。

微球种类及工艺
微球种类繁多，根据形貌可分为实心微球、双层微球、中空微球、多孔微球。

根据材质的不同，微球可分为无机微球和有机微球。

在制备微球时，有多种方法可供选择，如溶剂挥发法、喷雾干燥法、相分离法、微流体技术、静电喷射法等。

微球制剂的材料选择也非常重要。

目前微球制剂材料可分为天然来源的聚合物和人工化学合成的聚合物两类。

天然来源的聚合物价格低廉且来源广泛，可分为多糖和蛋白质类等，如葡聚糖、壳聚糖、海藻酸盐、淀粉、明胶、白蛋白等。

天然来源的聚合物对纯化有着较高的要求，当作为微球辅料用于大批量生产时较难保持批次间严格的质量标准。

常用的化学合成聚合物可分为聚酯、聚酸酐、聚磷腈、聚酰胺、聚磷酸酯等。

其优点是可以通过人为控制聚合制备工艺，来保证药用辅料级别的质量。

当作为载药微球的骨架材料时，聚合物材料还可以通过改变黏度及分子量等参数，灵活地控制载药微球的降解速度，以调节所包埋药物的释放速率。

另外对聚合物材料或微球表面进行特异性修饰能使微球具有主动靶向性，精准定位到病灶区域或改变释放行为，因此化学合成的聚合物是微球研究及生产原料的主要来源。

如需更多与微球有关的信息，建议咨询材料科学专家或查阅相关文献资料。

二氧化硅空心微球的制备方法及其作为药物载体的展望杨开;许正新【摘要】随着纳米技术的不断发展，二氧化硅空心微球在生物化工、医药、光学、催化、复合材料等领域有着广阔的运用前景。

本文将二氧化硅空心微球作为药物载体的优势进行阐述，并对近几年二氧化硅空心微球的制备方法进行综述，对其在药物制剂领域的发展进行展望。

【期刊名称】《药学研究》【年(卷),期】2016(035)010【总页数】3页(P602-604)【关键词】二氧化硅空心微球;药物载体;制备方法【作者】杨开;许正新【作者单位】[1]扬州大学广陵学院,江苏扬州225001;[2]扬州大学医学院,江苏扬州225001【正文语种】中文【中图分类】R944.271.1 常规高分子材料的特点目前，用于缓释制剂的主要基质仍是各种有机高分子材料，包括天然高分子材料，如明胶、壳聚糖等，半合成高分子化合物，如EM、CAP、EC等，以及合成高分子材料，如聚乳酸、聚氨基酸等3大类。

其中，天然高分子材料具有稳定、毒性小、成膜性好、黏度大等特点，目前依然是微球的主要载体材料。

然而由于其主要来源于壳聚糖、蛋白质、海藻盐类等天然产物，资源有限，且实际使用效果不佳［6］，因此在实际应用过程中还存在着不少问题。

对于半合成和合成的高分子材料，其生物相容性较差，在体内较难降解，且有些材料对酸、碱敏感，易在体内分解，甚至有一定的致敏作用，容易引发机体炎症，从而对组织、细胞造成伤害。

因基于上述高分子材料的特点，将二氧化硅空心微球作为新型的药物载体进行开发、利用这一思路已逐渐引起国内外专家的注意和重视。

1.2 二氧化硅空心微球的主要优势二氧化硅空心微球作为一种新型无机材料，其粒度分布范围窄、分散性好、稳定性好、熔点高、比表面积大等特点具有较为广阔的发展前景，如生物化工、医药、光学、催化、复合材料等方向。

由于其原材料丰富、无毒，且药物释放量可控等特点，加之二氧化硅空心微球的制备技术不断地发展，使得其在药物载具方面逐渐展示出自己的独特优势。

【技术】如何制备碳酸钙空心微球？碳酸钙空心微球由于其比表面积大、密度低，同时具有机械和热稳定性、良好的生物相容性和可降解性等优点，可广泛用于医药、化妆品、基因载体等领域。

碳酸钙空心微球的制备主要有CO2气体扩散法和复分解法等，通过有机添加剂或模板剂的调控作用，获得各种晶型和形貌的碳酸钙空心微球。

【1】复分解法制备碳酸钙空心微球以聚丙烯酸和十二烷基磺酸钠为有机添加剂，以Na2CO3和CaCl2为原料，采用复分解法制备粒径均匀、具有方解石和球霰石复合晶型的碳酸钙空心微球。

（1）碳酸钙空心微球的制备预先准确制备0.1mol/L的Na2CO3溶液、0.1mol/L的CaCl2溶液和一定浓度的聚丙烯酸溶液。

取出两份聚丙烯酸（25mL）溶液，分别加入到Na2CO3溶液（100mL）和CaCl2溶液（100mL）中，低速搅拌0.5h。

将一定浓度的十二烷基磺酸钠溶液只加入到装有Na2CO3和聚丙烯酸的混合溶液的三口烧瓶中，然后调转速为200r/min，将CaCl2和聚丙烯酸混合溶液快速倒入此三口烧瓶中，在一定温度、转速为200r/min的条件下，保持反应1h。

所得的CaCO3产物经过滤，用去离子水和无水乙醇各洗涤2次后，放入80℃的真空干燥箱中干燥24h后，即得到白色粉末（碳酸钙空心微球样品）。

（2）最佳制备工艺当反应温度为80℃、聚丙烯酸浓度为0.5g/L、十二烷基磺酸钠浓度为10mmol/L时，所得碳酸钙空心微球均为球形，且大小分布均匀，其粒径范围在4-7μm，从破损的微球中可以看到明显的空心结构。

图1 碳酸钙空心微球的SEM图从上图可看出：所得碳酸钙空心球的壳壁厚度约为300nm，空腔直径约为4μm，进一步观察发现，所示碳酸钙空心微球的表面不太光滑，绝大部分碳酸钙空心微球由无数纳米粒子相互堆积而成，这些纳米粒子的平均粒径约为250nm。

【2】碳酸钙空心微球的形成机理图2 碳酸钙空心微球形成机理碳酸钙空心微球整个形成过程可分为3个阶段：第一阶段：由于聚丙烯酸与钙离子的静电作用，致使聚丙烯酸链上的钙离子过饱和度高，优先形成无定形碳酸钙，而十二烷基磺酸钠由于超过了其临界胶束浓度，在表面张力和静电引力的作用下，溶液中的十二烷基磺酸钠胶束会使无定形碳酸钙形成球状结构。

Published online 26July 2016 | doi: 10.1007/s40843-016-5046-1Sci China Mater 2016,59(7):567–573Novel synthesis of V 2O 5hollow microspheres for lithium ion batteriesLu Zeng 1,2,Anqiang Pan 2*,Shuquan Liang 2,Jinbin Wang 1*and Guozhong Cao 3ABSTRACT In this work,hollow structured V 2O 5micro-spheres were fabricated from solid vanadium precursor microspheres which were prepared by microwave-assisted,solvothermal approach.In the annealing process,the spher-ical precursor microspheres can be converted into hollow microspheres,serving as a sacrificial template.The synthesis approach is quite different from the previously reported approaches for the preparation of hollow structured V 2O 5microspheres.As cathode materials for lithium ion batter-ies,the hollow-structured V 2O 5microspheres exhibit high capacity and good rate capability.The electrodes deliver specific discharge capacities of 132and 113mA h g −1at the current densities of 1C and 8C,respectively.Keywords: vanadium oxides,solvothermal,microwave-assisted synthesis,hollow microspheres,lithium ion batteriesINTRODUCTIONVanadium pentoxide (V 2O 5)has been extensively studied as a potential cathode material in rechargeable lithium-ion batteries (LIBs),due to its high capacity,abundant re-sources of vanadium elements in storage,and easy fab-rication [1–5].However,the low diffusion coefficient of lithium ions (10−12to 10−13cm 2s −1)[6]and low electronic conductivity (10−2to 10−3S cm −1)[7]impede its elec-trochemical performance.Recently,nanomaterials are effective to improve their electrochemical performance because of the kinetic enhancement for Li +ions diffusion and electron transportation [7–15].To date,various V 2O 5nanostructures,such as nanofibers [16,17],nanowires [18]and hierarchical microspheres [19–22]have been reported with improved electrochemical properties.Among the nanostructured materials,hierarchical nan/omicrostructures are preferred because the self-aggre-gation upon cycling can be inhibited at some extent.Inparticular,hollow structured vanadium oxides are of great interest,due to their structural advantages.First,the hol-low interior can better accommodate the volume change upon cycling.Second,the porous exterior shell allows the easy penetration of the electrolyte.Third,the nanopar-ticles which compose the microsphere can increase the contact area between electrode and electrolyte,which ensures the good rate capability of the electrode materials.To date,the synthesis strategies of hollow V 2O 5micro-spheres can be generally grouped into two classes:the Ostwald-ripening [9,19]and template-assisted fabrication [20].For Ostwald-ripening synthesis,the hollow precur-sors are initially formed during the solvo/hydrothermal process and can be converted into V 2O 5microspheres in the subsequent annealing process in air.For instance,Pan et al .[9]successfully fabricated hollow structured VO 2mi-crospheres with complex interiors and converted them into V 2O 5microspheres with well-preserved structures,which exhibited high capacity and tunable electrochemical prop-erties.Template-assisted synthesis of V 2O 5microsphere is a straightforward approach by first growing vanadium precursor against the templates and removing the tem-plates thereafter.More recently,Wu et al .[20]reported the growth of vanadium precursors by template against carbon microspheres and their conversion into multi-shelled V 2O 5microspheres in the subsequent annealing in air.The pre-pared double-shelled V 2O 5microspheres exhibited high specific discharge capacity and good stability.Cao et al .[23]reported the polyol synthesis of nanorod-assembled hollow microspheres using polyvinyl pyrrolidone (PVP)as a surfactant.The structures of the V 2O 5microspheres were pre-fixed by the precursor microspheres.However,the synthesis of hollow V 2O 5microspheres from solid1School of Materials Science &Engineering,Xiangtan University,Xiangtan 411105,China2School of Materials Science &Engineering,Central South University,Changsha 410083,China 3Department of Materials Science &Engineering,University of Washington,Seattle 98195,USA *Corresponding authors (emails:pananqiang@ (Pan S);jbwang@ (Wang J))567microspheres has been rarely reported.The difficulty may be raised from the synthesis of uniform vanadium organic precursor microspheres,which may create hollow interiors due to their large volume shrinkage upon annealing at high temperature.The microwave-assisted synthesis method as a rapid heating route for the fabrication of nanomaterials attracts increasing interests,which also shows some other advan-tages such as environmental friendliness,low cost and easy mass production in a short bining microwave synthesis with hydrothermal process presents a poten-tially faster,more efficient and selective method for the preparation of nanomaterials.Herein,we report the new preparation of hollow structured V2O5microspheres from the microwave-assisted,solvothermally prepared solid microspheres by a thermal induced annealing,in which the solid microspheres function as sacrificial templates. As cathode materials for lithium ion batteries,the V2O5 hollow microspheres exhibit high capacity and good rate capability.EXPERIMENTAL SECTIONSynthesis of V2O5hollow microspheresAll chemicals were of analytical purity and used as received without further purification.In a typical synthesis,200mg of V2O5,4mL of glycerol were dissolved into20mL of iso-propanol under magnetically stirring for30min to get yel-low slurry,which was then sealed in a Teflon-lined auto-clave and kept at3W,180°C for1h in a microwave reac-tor(MDS-6GSMART,Shanghai).After cooling down nat-urally,the dark brown precipitate was collected by centrifu-gation and washed with ethanol several times before dry-ing in an electrical oven at70°C.The dried solid precursor was annealed in air at400°C for1h to obtain V2O5hol-low microspheres.The temperature ramping rate was0.5°C min−1.Materials characterizationThe crystallographic phases of all the products were in-vestigated by powder X-ray diffraction(XRD,Rigaku D/max2500)with Cu Kα(λ=1.5406Å)radiation.The morphologies of the samples were characterized by field emission scanning electron microscope(FESEM,FEI Nova NanoSEM230),transmission electron microscopy(TEM, JEOL-JEM-2100F)and high resolution transmission electron microscope(HRTEM,TecnaiG2F20).Thermo gravimetric(TG)and differential scanning calorimetry (DSC)analyses were performed on a combined TG and DSC analysis instrument(Netzsch STA449C,Germany).Electrochemical measurementsThe working electrode was prepared by dispersing V2O5, carbon black(Super P-Li)and poly(vinylidene fluoride) (PVDF)binder in N-methylpyrrolidone with a weight ratio of70:20:10to form a slurry,which was coated on an alu-minum foil and dried in a vacuum oven at100°C for20h. The electrode disks were1.2cm in diameter and had an ac-tive material loading of0.6–0.9mg cm−2.Lithium foil was used as the counter and reference electrode,and1.0mol L−1LiPF6in ethyl carbonate/dimethyl carbonate(1:1v/v ratio)was used as the electrolyte.The cyclic voltammetry (CV)measurements were performed on an electrochemi-cal workstation(CHI604E,China)in the voltage range of 2.5–4V vs.Li/Li+under a scan rate of0.1mV s−1.The gal-vanostatic charge/discharge performance of the electrodes was evaluated at room temperature using a Land battery tester(Land CT2001A,China).RESULTS AND DISCUSSIONThe possible formation mechanism of the V2O5hollow spheres is shown in Fig.1.The commercial V2O5powder may experience a dissolution and recrystallization process in the mixed solvents of isopropanol during the solvother-mal process.The V5+from V2O5is partially reduced to V4+ by the organic species and the V2O5particles are converted into V4O9solid microspheres with organic species.In the later annealing process,the organic species in the solid spheres are decomposed,resulting in a volume contraction to create the interior hollow space.At the same time,the vanadium oxide is oxidized into V2O5microspheres. Fig.2a shows the XRD patterns of the solvothermally prepared precursor and its annealing product.Two main broad peaks are detected in the XRD pattern of the solvothermally prepared precursor and the whole pattern is in good agreement of the XRD pattern of V4O9 (JCPDS card23-0720).The broad peaks suggest the low crystallinity or small crystallites of V4O9in the precursor. Moreover,the valence of V5+in V2O5was partially reduced to V4+in the solvothermal process[24,25].After annealing the microsphere precursor in air,orthorhombic V2O5 phase(space group:Pmmn(59),JCPDS card41-1426) can be obtained with high purity.The phase transition from precursor to V2O5crystallites was studied by TG and DSC analysis and the result is shown in Fig.2b.The initial weight loss below279°C can be attributed to the evaporation of physical or chemical bounded water.The detection of a fast weight loss between279and370°C and an exothermal peak at321o C indicate the existence of organic species in the solvothermal prepared precursors.568Figure 1 Schematic illustration of the formation mechanism of the V 2O 5hollow spheres.Figure 2 (a)XRD patterns of the microwave-assisted solvothermally prepared product (black curve)and its annealing product (red curve);(b)TG and DSC results of the solvothermal products from room temperature to 600°C in air.The temperature ramping rate was set to 10°C min −1.As we know,the simple phase changes from V 4O 9to V 2O 5will cause the weight increase during annealing process.However,the large weight loss (about 10%)is related to the large amount of organic species in the vanadium precursor.The slight weight increase above 380°C can be attributed to the oxidation of vanadium species into V 2O 5.According to the TG and DSC analysis result,400°C was selected as the annealing temperature for the calcination process in air.Fig.3shows the structural characterization results of the vanadium precursor and the annealed V 2O 5.Fig.3a shows the SEM image of the solvothermally prepared pre-cursor particles,which are of spherical morphology with a mean diameter of about 1μm.The energy dispersive X-ray spectroscopy (EDS)result (inset of Fig.3b )indi-cates the precursor microspheres are composed of C,V and O.The clear detection of C element in the precursor mi-crospheres suggests the existence of organic species in the precursor microspheres.The result is in good agreement with the TG and DSC results.The TEM image (Fig.3c )reveals the solid interior of the microspheres.The struc-tures of the obtained V 2O 5from the solid vanadium pre-cursor are also characterized.Fig.3d shows the spherical morphology of the obtained V 2O 5with a mean diameter of about 1μm.However,the surface of the microspheres be-comes rough and porous.The surface structural changes can be attributed to the removal of organic species dur-ing the annealing process,which creates the pores on the surface.In general,the spherical morphology is well re-tained.The TEM image of the V 2O 5microspheres (Fig.3e )clearly presents the hollow interiors of the V 2O 5mi-crosphere and the porous feature of the exterior shell.The HRTEM image (Fig.3f )shows the layer fringes of 0.5714nm for V 2O 5hollow microspheres,in good agreement with the planar distance of (200)lattice planes.The selected area electron diffraction (SEAD)pattern (inset of Fig.3f )also confirms the good crystallinity of the obtained V 2O 5hol-low microspheres.It is worth mentioning that the forma-tion of V 2O 5hollow microspheres reported in this work is quite different from the previously reported synthesis strategy [26],such as Ostwald-ripening mechanisms [13]and template-assisted synthesis [20].The formation of the hollow microsphere can be attributed to the volume con-traction of the solid spheres after removing the organic species during the calcination process in air.The removal of organic species creates the porous feature of the exterior shells.In the whole process,the solid microspheres are ro-bust enough and can serve as self-sacrificial templates for the construction of the hollow microspheres.Fig.4a shows the Raman spectra of the V 4O 9solid spheres.The peaks located at 96,140, 191, 282, 403,528,569Figure 3 FESEM images (a and b),the EDS (inset of b)and TEM image (c)of the solvothermally prepared product;FESEM image (d),TEM (e),HRTEM image (f)and the SAED pattern (inset of f)of the calcination product.688and 990cm −1are ascribed to the characteristic peaks of V 4O 9[27,28],which is in good agreement with XRD re-sults.The hierarchical nature of the V 2O 5porous hollow spheres is further evaluated by nitrogen adsorption-des-orption measurement and the results are shown in Fig.4b .The isotherm can be described as type II with a H3hys-teresis loop,which indicates the slit-shaped pores in the V 2O 5porous hollow spheres.The measured Brunauer-Em-mett-Teller (BET)surface area of the sample is about 12.146m 2g −1.Barrett-Joyner-Halenda (BJH)calculations disclose that the pore size distribution is mainly in the range of 1–20nm,which is in good correspondence with the TEM image.The V 2O 5hollow microspheres were assembled into coin cells to evaluate their electrochemical performances,and the results are shown in Fig.5.Fig.5a shows five consec-utive CV cycles for the V 2O 5hollow microspheres.During the cathodic scan,two peaks at 3.3and 3.1V vs .Li/Li +cor-respond to the phase transition from α-V 2O 5to ε-Li 0.5V 2O 5,and then to δ-LiV 2O 5,respectively [29,30].During the an-odic scan,the peaks at 3.26and 3.48V are attributed to the Li +de-intercalation process,corresponding to the phase changes from δ-LiV 2O 5,to ε-Li 0.5V 2O 5and then to α-V 2O 5,in reverse [31–33].The large overlap of the CV curves in-dicates the good reversibility of the V 2O 5hollow micro-spheres.Fig.5b shows the discharge/charge profiles of the V 2O 5hollow microspheres at different C-rates.The multi-ple discharge/charge plateaus at different rates indicate the multi-step Li +ions intercalation/de-intercalation process,in good agreement with the CV result.Even at 4C,the plateaus can be still clearly detected.Fig.5c shows the rate performance of the hollow structured V 2O 5electrodes.A specific discharge capacity of 136mA h g −1can be delivered at 1C,which is quite close to the theoretical capacity of 147mA h g −1for one Li +ion intercalation per formula.The electrodes deliver the capacities of 133.0,129.4and 113.8mA h g −1at 2C,4C and 8C,respectively.Even at 16C,the electrode can release a capacity of 86.8mA h g −1.The re-sults demonstrate the good rate capability of the electrodes.Fig.5d shows the cycling performance ofthe hollow struc-Figure 4 (a)Raman spectra of the V 4O 9solid spheres;(b)nitrogen adsorption-desorption isotherm of the V 2O 5porous hollow spheres,and the pore size distribution of the V 2O 5porous hollow spheres (inset of b).570Figure5 (a)CV curves of the V2O5microspheres at a scan rate of0.1mV s−1;(b)discharge/charge profiles and;(c)rate performance of the V2O5 microspheres at various rates in the voltage range between2.5–4.0V vs.Li/Li+;(d)long-term cycling performance of the V2O5microspheres in the voltage range of2.5–4.0V at5C and10C.Here1C=147mA g−1.tured V2O5microspheres at the rates of5C and10C.The electrodes exhibit an initial discharge specific capacity of 130mA h g−1at5C and retain the capacity of111.8mA h g−1after500cycles,with an average capacity fading rate of0.3%per cycle.The electrodes also show good capacity retention at10C.The capacity fading rate is0.5%per cy-cle.Moreover,the Coulombic efficiency of the electrode is very close to100%.All the electrochemical results indicate the good electrochemical performance of the V2O5hollow microspheres,which can be attributed to their structural advantages:(1)the hollow interiors can better accommo-date the volume change upon cycling;(2)the porous ex-terior shell allow the easy penetration of the electrolyte;(3) the large surface area can increase the contact area between electrode and electrolyte,which ensures the good rate ca-pability of the electrode materials. 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11:1990–199833Qin M,Liang Q,Pan A,et al.Template-free synthesis of vanadium oxides nanobelt arrays as high-rate cathode materials for lithium ion batteries.J Power Sources,2014,268:700–705 Acknowledgments This work was supported by the National Natural Science Foundation of China(51302323),the Program for New Century Excellent Talents in University(NCET-13-0594),and the Natural Science Foundation of Hunan Province(14JJ3018).Author contributions Zeng L carried out the main experiment and wrote the paper;Pan A and Wang J made the research plan and revised the manuscript.Liang S and Cao G participated the data discussion. Conflict of interest The authors declare that they have no conflict of interest.572Lu Zeng received her bachelor degree from Hunan University of Technology in2013.She is currently a graduate student at the School of Materials Science and Engineering,Xiang Tan University.She worked in Prof.Anqiang Pan’s group in2015. Her current research focuses on hollow-structured materials for electrochemical energy storage application.Anqiang Pan received his BSc(2005)and PhD(2011)degrees in materials physics and chemistry from Central South Uni-versity.He worked at the University of Washington,Pacific Northwest National Laboratory and Nanyang Technological University and joined Central South University as a Sheng-Hua Professor in2013.His current interests are on lithium ion batteries,and supercapacitors.573。

中空ZSM-5分子筛微球及其吸附与催化性能孙莉莉;闫凯;罗稳;周健【摘要】首先利用聚乙二醇作为软模板合成出具有一定介孔结构的ZSM-5分子筛微球,再通过快速可控碱刻蚀的方法,成功制备出尺寸均一的中空分子筛微球.利用X 射线衍射(XRD)、氮气吸附等温线分析(N2 isotherm)、扫描和透射电子显微镜(SEM,TEM)对所制备的中空分子筛微球进行了表征,并研究了中空分子筛微球对有机物废水的吸附性能和对大分子的催化裂解性能.结果表明,刻蚀后分子筛结晶度略有下降,但是介孔度和孔体积明显提升.中空分子筛微球外径在600 nm,壳层厚度在100 nm左右.此外,该中空结构不仅对苯等有机分子具有吸附富集作用,其饱和吸附量几乎达到了常规分子筛微球的3倍,并且六次循环使用后的吸附容量依然保持基本不变,显示出较高的吸附容量和循环使用稳定性.在异丙苯和三异丙苯裂解反应中中空分子筛微球也显示出较高的催化活性.【期刊名称】《无机材料学报》【年(卷),期】2016(031)008【总页数】7页(P834-840)【关键词】中空分子筛微球;碱刻蚀;吸附;苯废水;催化裂解【作者】孙莉莉;闫凯;罗稳;周健【作者单位】黄河水利职业技术学院,开封475003;黄河水利职业技术学院,开封475003;河南大学河南省天然药物与免疫工程重点实验室,开封475004;中国石化上海石油化工研究院,上海201208【正文语种】中文【中图分类】TQ174中空微球是一类备受关注的具有重要功能的结构材料[1-2], 内部的空腔赋予其低密度、高比表面积等性质, 更重要的是, 通过将特定组分封装入空腔中, 可以形成具有特殊功能的核/壳复合微球颗粒。

因此中空微球在催化、环境保护和生物医药等领域具有重要的应用前景[3-5], 其组成已经从碳、金属以及聚合物扩展到无机氧化物等[6-8]。

近年来, 具有中空结构的氧化硅微球的合成与应用探索成为无机材料研究中的一个热点, 但是到目前为止, 绝大部分文献报道的氧化硅微球是无定形的氧化硅[2, 3, 5], 这使其在苛刻条件下或者长时间、多次循环中的应用受到限制。

单分散中空二氧化硅微球的制备万恒成;段涛;竹文坤;姚卫棠;易欢;程文财;牛振威【摘要】Through sacrificing micron grade PS template synthesis method in situ preparation of micron grade hollow monodisperse SiO2 microspheres,this paper mainly studied the effect of such parameters as temperature reflex(50,70 ℃),TEOS usage(2,3,4 g),dosage of ammonia (1,2,3 mL) and dosage of MTC(0.2,0.4 g) on the silica microspheres,thus obtaining the best preparation technology of micronlevel (1-5 microns),and structure (hollow degree,wall thickness,etc.) of controllable monodisperse hollow SiO2 microspheres.The performance of the microspheres was represented through testing methods such asSEM,TEM,FT-IR,TGA and BET.%通过牺牲微米级PS模板原位合成方法制备微米级单分散中空SiO2微球,着重研究反应温度(50,70℃)、TEOS用量(2,3,4 g)、氨水用量(1,2,3 mL)与MTC用量(0.2,0.4g)等参数对中空微球的影响,获得微米级(1～5μm)、结构(孔径、壁厚等)可控的单分散中空SiO2微球的最佳制备工艺,通过扫描电镜分析(SEM)、透射电镜分析(TEM)、红外光谱分析(FT-IR)、热失重分析(TGA)、氮吸附(BET)等测试手段表征了微球性能.【期刊名称】《西南科技大学学报》【年(卷),期】2017(032)004【总页数】6页(P1-6)【关键词】中空二氧化硅微球;牺牲模板法;微米级微球【作者】万恒成;段涛;竹文坤;姚卫棠;易欢;程文财;牛振威【作者单位】西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900;西南科技大学新能源材料研究中心四川绵阳621900【正文语种】中文【中图分类】TB321近年来，空心微球作为一种新型功能材料已经广泛应用于化学、生物医药和材料领域中，如被用作催化剂载体、填料、涂料、控制释放微胶囊材料(药物、颜料、化妆品、油墨和生物活性试剂)等[1]。