中空Ta_2O_5/TiO_2复合光催化剂的可控氧化制备及性能

以钛粉、钽粉为原料,炭黑作为反应性模板,通过熔盐法在炭黑表面原位生长了TaTiC_2纳米碳化物涂层,并以所得TaTiC_2/C复合物为碳化物前驱体,再经可控氧化制备出中空Ta_2O_5/TiO_2复合光催化剂。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见(UV-Vis)漫反射(DRS)及N2物理吸附等手段对所制备的光催化剂进行形貌、显微结构及孔结构表征。以高压汞灯为紫外光源,以亚甲基蓝为目标降解物,通过光催化降解实验评价中空Ta_2O_5/TiO_2复合光催化剂的光催化活性。结果表明,熔盐法生长碳化物涂层厚度均匀(20~30 nm),碳化物主要以TaTiC_2晶相存在且具有纳米级的颗粒尺寸。中空Ta_2O_5/TiO_2复合光催化剂同时具有200 nm左右的中空大孔结构及壳层10 nm左右的介孔结构。中空大孔和介孔的存在提高了所制备催化剂对亚甲基蓝的吸附能力。此外,TiO_2与Ta2O5通过电子能带结构的耦合,有效提高了光生电子和空穴的分离效率,从而显著提高了光催化活性。nTi∶nTa=2.5∶1.5时,相应的中空Ta_2O_5/TiO_2复合光催化剂表现出最佳的光催化活性,对亚甲基蓝的紫外光催化降解率高达97%。     

三维有序介孔/大孔TiO2微球的制备、表征及光催化性能

以聚甲基丙烯酸甲酯微球为模板,分别以钛酸四丁酯和四异丙醇钛为钛源,通过溶胶-凝胶法辅助模板法制得TiO2纳米微球前驱体,并用程序升温控制其焙烧温度,最终成功制得了具有三维有序介孔/大孔复合结构的TiO2微球.以罗丹明B(RhB)为模型污染物,探索了以不同钛源制备得到的介孔/大孔复合TiO2微球的光催化性能;并采用XRD、SEM、TEM、UV-vis DRS、比表面积测试、光催化性能测试等对样品的晶粒尺寸、物相、形貌、光吸收、比表面积及性能等进行了分析.结果表明,运用溶胶凝胶法辅助模板法能够合成结晶度高、形貌规整、比表面积大、光催化活性良好的锐钛矿相TiO2微球.     

苯乙烯和N-乙烯基吡咯烷酮共聚物/Ag复合微球的制备及性能研究

首先用无皂乳液聚合法制备了单分散聚苯乙烯(PSt)乳液,以此为种子乳液,使用N,N-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸钾(KPS)为引发剂,进行苯乙烯和N-乙烯基吡咯烷酮(NVP)共聚合制备了以PSt为核、St和NVP共聚物为壳的具有核-壳结构的聚合物微球(P(St-NVP)).以此微球为模板通过化学沉积法得到了粒径分布均匀、单分散的P(St-NVP)/Ag复合微球.傅里叶红外光谱、X-射线衍射、扫描电镜、透射电镜、激光粒度仪和紫外-可见光谱对复合微球的结构、形貌、物相及催化性能进行了表征.结果表明,P(St-NVP)/Ag复合微球具有规则的球形结构,粒径在400～700 nm之间,随交联剂浓度或种子乳液浓度的增加,复合微球粒径减小.粒径在十几个纳米左右的银粒子均匀分布在微球表面和内部.载银复合微球在NaBH4还原4-硝基苯酚为4-氨基苯酚的模型反应中表现出较高的催化活性.     

TiO_2微球的合成及其作为散射层在量子点敏化太阳能电池中的应用（英文）

以十六烷基三甲基溴化铵(CTAB)为模板剂,通过TiCl4在乙醇水溶液中的直接水解,制备了介孔TiO2微球.X射线衍射(XRD)结果表明所制备的微球晶型为金红石,扫描电镜(SEM)结果显示微球的直径大约为700nm,由粒径约为16 nm的小颗粒堆积而成.通过刮涂法制备了在TiO2小颗粒层上涂覆有作为散射层的TiO2微球和未涂覆微球的薄膜.并通过化学浴沉积(CBD)的方法在膜上生长CdS/CdSe量子点,得到了量子点敏化太阳能电池(QDSCs).紫外吸收和漫反射结果表明,这种微球结构有利于量子点的沉积,具有较强的光散射作用,有效地增加了光线的收集,从而提高了电池的光电流,最终得到了4.5%的光电转换效率,比不加散射层的电池的效率高27.7%,也比利用传统散射层(由20 nm TiO2小颗粒和400 nm TiO2固体颗粒组成)的电池效率高10.2%.我们把电池效率的提升归因于较强的光散射作用和较长的电子寿命.     

三维有序大孔钙钛矿 LaFeO3 催化剂的制备及其催化炭黑颗粒燃烧性能

 采用水油两相双引发剂的无皂乳液聚合法制备了羧基改性的聚甲基丙烯酸甲酯 (PMMA) 聚合物微球, 并以此为模板, 采用胶体晶体模板法制备了三维有序大孔 (3DOM) 钙钛矿 LaFeO3 催化剂. 同时采用柠檬酸络合燃烧法制备了纳米钙钛矿 LaFeO3 催化剂. 通过傅里叶红外光谱、扫描电镜、X 射线衍射和激光粒度仪等方法对样品进行了表征. 采用程序升温氧化反应评价了催化剂对模拟柴油机炭黑颗粒催化燃烧的活性. 结果表明, 制备的羧基改性 PMMA 聚合物微球固含量约为 10%, 表面羧基含量约为 3 mmol/g. 微球粒径分布均匀, 且可通过调节反应条件得到不同的粒径, 可控范围在 300~700 nm. 所制得的 3DOM 钙钛矿 LaFeO3 催化剂以六方有序的方式排列, 其孔径及孔径收缩率分别为 300 nm 和 32%, 大孔孔壁平均厚度约 50 nm. 该催化剂对炭黑颗粒催化燃烧的 T10, T50, T90 和 SmCO2 分别为 340, 412, 458 oC 和 99.8%, 性能优于纳米 LaFeO3 催化剂.     

基于聚合物中空微球构建膜内纳米空腔及其对气体渗透性能的影响

分别以四氢呋喃丙烯酸酯和双季戊四醇六丙烯酸酯为油相反应单体和交联剂,利用界面引发剂在无表面活性剂微乳液油水界面处引发聚合,制备了中空微球,浇铸形成具有纳米空腔的中空微球膜.考察了膜内纳米空腔对分离膜气体渗透性和分离性的影响.结果表明,制备的中空微球平均粒径为116. 7 nm,中空结构明显,壳层厚度为10～20 nm;中空微球膜的渗透分离性能较壳层材料的本征值有显著提升,在35℃,0. 2 MPa条件下,CO_2的渗透系数增大1. 4～5. 7倍,且分离系数也有所提升.     

空心锌铬铁氧体/二氧化钛复合物的制备及去污性能

以葡萄糖溶液为原料,通过水热法制备了分散性良好的碳微球;以碳微球为模板,应用化学沉淀法和热处理技术除去碳核获得空心铬锌铁氧体;用钛酸四丁酯作为钛源,在空心铁氧体表面包覆二氧化钛制备了锌铬铁氧体/二氧化钛二元复合物.采用现代分析技术表征了制备样品的微观结构、形貌和电磁性能,并对其吸附和降解染料废水的性能进行了研究.结果表明,Zn Cr_(0.25)Fe_(1.75)O_4对染料废水具有较好的去污效果,对甲基橙和罗丹明B的去污效率分别为87%和83%;TiO_2对铁氧体的包覆能提高复合物对染料废水的光催化降解性能,其中m_(T/ZCF)=0.3的ZnCr_(0.25)Fe_(1.75)O_4/TiO_2复合物的去污效果最佳,几乎与纯二氧化钛相仿.     

Ag掺杂型空心TiO2纳米微球的制备与表征及其光催化性能

通过甲基丙烯酸与苯乙烯的乳液聚合制备了表面载有阴离子的聚苯乙烯(PSt)纳米乳胶粒. 在乙醇与水的混合溶剂中, 用硅烷偶联剂乙烯基三甲氧基硅烷对其进行表面改性. 以此乳胶粒为模板, 加入钛酸四丁酯和硝酸银制备了Ag₂O掺杂型聚苯乙烯/二氧化钛(PSt/TiO₂)复合微球. 对该微球在180 °C进行液相预处理、干燥、500 °C煅烧等步骤制备了Ag 掺杂型Ag-TiO₂复合粒子. 通过扫描电镜(SEM)、透射电镜(TEM)和X射线衍射(XRD)等手段对PSt/TiO₂复合粒子及Ag-TiO₂空心粒子的形貌及晶体结构等进行了表征. 考察了Ag-TiO₂复合粒子在紫外光(365 nm)与紫外-可见光(370-760 nm)下对罗丹明B (RhB)降解的催化活性. 结果表明, 与不含银的TiO₂空心微球相比, 在紫外光照射下, 银含量(n_Ag/n_Ti)为0.1%的Ag-TiO₂复合粒子对RhB的降解率提高了11%左右; 在紫外-可见光照射下, n_Ag/n_Ti为1.0%和2.0% 的Ag-TiO₂复合粒子对RhB的降解率提高了30%左右.     

具有广谱紫外屏蔽性能的三元共聚物微球的制备

以醋酸乙烯酯(VA)、 马来酸酐(MA)和商品化的紫外吸收剂2-{2-羟基-5-[2-(甲基丙烯酰氧)乙基]苯基}-2H-苯并三唑(NB)为单体, 偶氮二异丁腈(AIBN)为引发剂, 通过自稳定沉淀聚合法(2SP)制备了具有广谱紫外屏蔽性能的单分散三元共聚物微球(PVMN); 研究了溶剂、 单体配比、 引发剂用量、 单体浓度、 反应温度和反应时间对共聚物微球形态和性能的影响. 研究结果表明, 体积比为7∶3的苯甲酸乙酯/正庚烷混合溶剂是2SP法合成单分散PVMN微球的理想溶剂. 随着单体配比中紫外吸收单体NB比例的增加, 引发剂用量、 单体浓度、 反应温度的提高和反应时间的延长, 微球的粒径随之增大, 进而改变了微球的紫外屏蔽性能. 本文制备的微球的粒径范围为(249±19)~(1434±213) nm, 优化得到的PVMN微球可屏蔽约90%的紫外光. 该策略还可扩展到其它可用作紫外吸收剂的乙烯基单体, 是一种制备稳定高分子紫外屏蔽剂的通用方法.     

P(St-AM)核壳聚合物微球的制备及其光子晶体膜

采用一步乳液聚合法,调节引发剂用量,制备了不同粒径的具有核壳结构的功能性聚(苯乙烯-丙烯酰胺)乳胶微球.用透射电子显微镜表征了乳胶微球的核壳结构和粒径,所制微球的粒径分别为195,217,234和255 nm.用红外光谱对微球的化学成分进行了表征,证实聚丙烯酰胺已包覆在聚苯乙烯外层.通过竖直沉积自组装法制备了聚合物微球的光子晶体薄膜.扫描电子显微镜表征了所制光子晶体膜的表面形貌,反射和透射光谱表征了光子禁带.结果表明,聚合物微球以面心立方紧密堆积,其(111)面与基底平行;微球粒径不同,光子晶体的光子禁带不同.制备了不同光子禁带的光子晶体,禁带分别位于473,515,574和630 nm,相应的薄膜分别呈蓝色、绿色、黄色和红色,对于光子晶体的拓展和应用具有重要的意义.     

碳空心球/硫复合材料制备和电化学性能研究

采用PMMA为模板制备碳空心球材料,并以碳空心球材料为导电骨架与硫材料复合制得碳空心球/硫复合材料. SEM和TEM照片显示,硫材料能均匀地填充在碳空心球的孔道和腔体内部. 采用恒电流充放电测试碳空心球/硫复合电极的电化学性能. 结果表明,在100 mA·g^-1、500 mA·g^-1、1 A·g^-1、2 A·g^-1 和5 A·g^-1电流密度下,碳空心球/硫复合电极可逆放电容量分别为1145 mAh·g^-1、824 mAh·g^-1、702 mAh·g^-1、586 mAh·g^-1和395 mAh·g^-1,呈现出较优异的倍率循环寿命.     

Preparation of hollow titania and strontium titanate spheres using sol–gel derived silica gel particles as templates

A facile approach, based on polyelectrolyte-mediated electrostatic adsorption of a water-soluble titanium complex on colloidal templates and hydrothermal treatment, is presented for the formation of hollow titania (TiO₂) and strontium titanate (SrTiO₃) spheres. Monodispersed silica gel particles were prepared by the sol?Cgel method and adopted as core templates. Deposition of a water-soluble titanium complex, titanium (IV) bis(ammoniumlactato)dihydroxide (TALH), on the silica gel particles was carried out via the layer-by-layer assembly technique. Hollow spheres were successfully formed from the core?Cshell particles. The silica gel particles used as core templates dissolved during hydrothermal treatment because of the particles?? undeveloped siloxane network. In addition, the hydrothermal treatment induced crystallization of the hollow shells. Therefore, the hydrothermal treatment played two roles; removal of the silica templates and crystallization of the hollow shells. When deionized water was used, hollow TiO₂ spheres were obtained. Hollow SrTiO₃ spheres could also be formed when an aqueous solution of Sr(OH)₂ was used. The approach presented here could be exploited as a novel and sustainable approach for the fabrication of a range of different inorganic hollow spheres.     

纳米结构TiO2/PS及TiO2空心球的自组装与表征

以TiCl₄的盐酸溶液配制的TiO₂溶胶为前驱体, 以聚苯乙烯微球为载体, 在表面活性剂存在下, 通过逐层自组装技术制备了纳米结构TiO₂/PS及TiO₂空心球. 利用XRD, SEM, TG-DTA等对复合颗粒进行了表征. 研究表明: 纳米结构TiO₂/PS的组成、结构、形貌和粒度可通过溶胶酸度、组装时水解反应温度、煅烧温度、硫酸根的加入量来控制.     

分级微纳结构TiO2空心球的制备及其在DSSC中的应用

以钛酸四丁酯为钛源,无水乙醇为溶剂,通过碳球模板法制备出直径为200nm、壳厚20～25nm的TiO2空心球（HS）.通过X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）和N2吸附脱附等对产物的形貌、晶相组成、孔结构和紫外-可见光谱性质进行了表征,结果显示所制备的锐钛矿相TiO2空心微球是由初级结构纳米级TiO2晶粒构成的.将这种TiO2空心球应用于染料敏化太阳电池（DSSC）领域可以提高光阳极对光的散射.通过制备P25/HS-TiO2双层膜电极,相比单纯的P25纳米晶电极（Jsc=13.5mAcm？2,Voc=0.653V,FF=0.53,η=4.95%）可以得到更高的光电转化效率（Jsc=15.79mAcm？2,Voc=0.653V,FF=0.55,η=6.66%）.     

Synthesis and photonic band calculations of NCP face-centered cubic photonic crystals of TiO2 hollow spheres

With the help of self-assembly, thermal sintering, selective etching techniques and sol-gel process, the non-close packed (ncp) face-centered cubic (fcc) photonic crystals of titanium dioxide (TiO2) hollow spheres connected by TiO2 cylindrical tubes have been fabricated using silica template. The photonic bandgap calculations indicate that the ncp structure of TiO2 hollow spheres was easier to open the pseudogaps than close packed system at the lowest energy.     

Preparation of Porous Hollow SiO2 Spheres by a Modified St?ber Process Using MF Microspheres as Templates

Using the surface charged and acid dissolvable melamine formaldehyde (MF) microspheres as sacrificial hard templates, silica coated MF core?Cshell composite microspheres, denoted as MF@SiO₂, were synthesized via a surfactant-assisted sol?Cgel process by using tetraethyl orthosilicate (TEOS) as silica source. Hollow SiO₂ spheres with mesoporous shells were then obtained after selective removal of the MF cores and the pore directing surfactant by hydrochloric acid etching or calcinations in air. Interesting shrinkage phenomena were observed in both the hollow products derived from hydrochloric acid etching and calcinations. The influence of the ratio of MF sphere to TEOS and the removal method of the MF core on the size of the hollow spheres, the shell thickness and the shell surface roughness have been studied. The composition, the thermal stability, the morphology, the surface area and pore size distribution, the wall thickness and adsorption properties of the hollow spheres derived from hydrochloric acid etching and calcinations were also investigated and compared based on the FTIR, SEM, TEM, TGA, Nitrogen adsorption?Cdesorption and spectrophotometer techniques or measurements.     

Use of carbonaceous polysaccharide microspheres as templates for fabricating metal oxide hollow spheres

A general method for the synthesis of metal oxide hollow spheres has been developed by using carbonaceous polysaccharide microspheres prepared from saccharide solution as templates. Hollow spheres of a series of metal oxides (SnO2, Al2O3, Ga2O3, CoO, NiO, Mn3O4, Cr2O3, La2O3, Y2O3, Lu2O3, CeO2, TiO2, and ZrO2) have been prepared in this way. The method involves the initial absorption of metal ions from solution into the functional surface layer of carbonaceous saccharide microspheres; these are then densified and cross-linked in a subsequent calcination and oxidation procedure to form metal oxide hollow spheres. Metal salts are used as starting materials, which widens the accessible field of metal oxide hollow spheres. The carbonaceous colloids used as templates have integral and uniform surface functional layers, which makes surface modification unnecessary and ensures homogeneity of the shell. Macroporous films or cheese-like nanostructures of oxides can also be prepared by slightly modified procedures. XRD, TEM, HRTEM, and SAED have been used to characterize the structures. In a preliminary study on the gas sensitivity of SnO2 hollow spheres, considerably reduced "recovery times" were noted, exemplifying the distinct properties imparted by the hollow structure. These hollow or porous nanostructures have the potential for diverse applications, such as in gas sensitivity or catalysis, or as advanced ceramic materials.     

Formation of Triple‐Shelled Molybdenum–Polydopamine Hollow Spheres and Their Conversion into MoO2/Carbon Composite Hollow Spheres for Lithium‐Ion Batteries

Unique triple‐shelled Mo‐polydopamine (Mo‐PDA) hollow spheres are synthesized through a facile solvothermal process. A sequential self‐templating mechanism for the multi‐shell formation is proposed, and the number of shells can be adjusted by tuning the size of the Mo‐glycerate templates. These triple‐shelled Mo‐PDA hollow spheres can be converted to triple‐shelled MoO₂/carbon composite hollow spheres by thermal treatment. Owing to the unique multi‐shells and hollow interior, the as‐prepared MoO₂/carbon composite hollow spheres exhibit appealing performance as an anode material for lithium‐ion batteries, delivering a high capacity of ca. 580 mAh g^?1 at 0.5 A g^?1 with good rate capability and long cycle life.     

Fabrication of hollow spheres of metal oxide using fructose-derived carbonaceous spheres as sacrificial templates

In this report, fructose-derived carbonaceous spheres were utilized as sacrificial templates for the fabrication of metal oxide hollow spheres (MOHSs) by a facile hydrothermal approach. Hollow spheres of a series of crystalline metal oxides (α-Fe₂O₃, Cr₂O₃, Co₃O₄, NiO, and ZnO) have been fabricated, utilizing the metal chloride as the oxide precursors. Heating of an aqueous solution of the metal chloride and fructose to moderate temperature in an autoclave affords a spherical composite consisting of a metal precursor shell sheathing a carbonaceous core. Subsequent removal of the interior carbonaceous cores by thermal treatment through oxidation in air produces free-standing crystalline oxides hollow spheres. The MOHSs were characterized by means of SEM, TEM, XRD, IR spectroscopy, energy dispersive X-ray (EDX) and sorption measurements. The results show convincingly that using fructose as a sacrificial template after application of a hydrothermal synthesis route could be a favourable sacrificial template for the fabrication of various MOHSs.     

Preparation, photocatalytic activities, and dye-sensitized solar-cell performance of submicron-scale TiO2 hollow spheres

We prepared submicron-scale spherical hollow particles of anatase TiO2 by using a polystyrene-bead template. The obtained particles were very uniform in size, with a diameter of 490 nm and a shell thickness of 30 nm. The Brunauer-Emmett-Teller surface area measurements revealed a large value of 70 m2/g. The photocatalytic property was investigated by the complete decomposition of gaseous isopropyl alcohol under UV irradiation. It was indicated that the activity of the hollow spheres was 1.8 times higher than that of the conventional P25 TiO2 nanoparticles with a diameter of 30 nm. Furthermore, we fabricated a dye-sensitized solar cell (DSC) using an electrode of the TiO2 hollow spheres, and examined the photovoltaic performance under simulated sunlight. Although the per-area efficiency was rather low (1.26%) because of a low area density of TiO2 on the electrode, the per-weight efficiency was 2.5 times higher than those of the conventional DSCs of TiO2.