核壳结构TiO2/Ag反蛋白石的制备与形貌观察

用化学还原法制备了银包覆聚苯乙烯(PS)微球结构,通过垂直沉积法排列出具有密堆积结构的PS-Ag蛋白石模板,然后采用溶胶-凝胶法渗透TiO2,最后焙烧处理除去PS,制备出了规整的核壳结构TiO2/Ag反蛋白石。采用扫描电镜、透射电镜和X射线衍射对该样品进行了分析。结果表明,PS球表面包覆的为纳米尺度的金属Ag;所制备的PS/Ag核壳微球蛋白石经过480℃、12h焙烧处理后获得的核壳TiO2/Ag反蛋白石结构的单胞参数可以通过调节包覆银层的厚度来调变,即改变AgNO3与PS球的质量比获得具有不同银包覆层厚度、不同单胞参数的三维蛋白石和反蛋白石结构。     

核壳结构TiO2/Ag反蛋白石的制备与形貌观察

用化学还原法制备了银包覆聚苯乙烯(PS)微球结构,通过垂直沉积法排列出具有密堆积结构的PS-Ag蛋白石模板,然后采用溶胶-凝胶法渗透TiO2,最后焙 烧 处 理 除 去PS,制 备 出 了 规 整 的 核 壳 结 构TiO2/Ag反蛋白石。采用扫描电镜、透射电镜和X射线衍射对该样品进行了分析。结果表明,PS球表面包覆的为纳米尺度的金属银;所制备的PS/Ag核壳微球蛋白石经过480℃、12h焙烧处理后获得的核壳TiO2/Ag反蛋白石结构的单胞参数可以通过调节包覆银层的厚度来调变,即改变AgNO3与PS球的质量比获得具有不同银包覆层厚度、不同单胞参数的三维蛋白石和反蛋白石结构。     

Ag-TiO_2空心复合微球制备及其光催化性能

为了提高空心TiO2的光催化活性和拓展其对可见光的响应,以聚苯乙烯为模板合成TiO2空心微球,再通过KBH4还原AgNO3,制备了TiO2空心壳层表面载有Ag单质粒子的复合微球。利用SEM、TEM、XRD和EDS对Ag-TiO2空心微球的形貌结构和组成进行表征,并以有机染料罗丹明B(RhB)为目标降解物,研究该复合微球的光催化性能。在紫外光下,载银量为2%的Ag-TiO2复合微球2h内对RhB的降解率比同条件下空心TiO2提高23.8%;在可见光下,载银量为2%的Ag-TiO2复合微球在6h内对RhB的降解率比同条件下空心TiO2提高28.2%。结果表明,壳层表面载有适量Ag单质粒子的空心TiO2复合微球,其光催化活性和对可见光的响应显著高于纯空心TiO2微球。     

反蛋白石结构三维有序大孔CeO_2的制备和性能EI北大核心CSCD

以单分散聚苯乙烯(PS)微球为构筑单元,用双基片垂直沉积方法制备高度有序的PS胶体晶体模板,再用模板法合成了具有反蛋白石结构的三维有序大孔CeO_2(3DOM-CeO_2)。用X-射线衍射仪(XRD)、场发射扫描电镜(FESEM)、高分辨透射电镜(HRTEM)、原子力显微镜(AFM)和N_2吸脱附等手段对样品微观结构进行了表征,并借助H_2-TPR分析了样品的还原性能。结果表明:PS胶体晶体模板排列高度有序,呈多层面心立方结构紧密堆积;所制备的3DOM-CeO_2具有三维周期性排列的多孔结构,其孔间距在280-300 nm,壁厚约为40 nm;样品的大孔骨架由粒径为5-10 nm的CeO_2颗粒所组成;与纳米CeO_2标样相比,3DOM-CeO_2样品具有更好的低温还原性能。     

微波辐照掺氮改性有序多孔TiO2微球制备与光催化性能研究

采用溶胶-凝胶法和胶体晶体模板法制备了有序多孔TiO2微球,在微波辐照条件下对其掺氮改性,利用FTIR、SEM、XRD、XPS分析等方法对掺氮TiO2材料进行表征,并研究掺氮前后TiO2材料的光催化性能。实验结果显示,所制备有序多孔TiO2微球整体较致密,但局部有孔洞塌陷。微波辐照前后有序多孔TiO2微球的晶型没有改变,依然为锐钛型。XPS分析发现微波辐照制备掺氮有序多孔TiO2微球是可行的,且有序多孔TiO2微球中氮元素质量分数约为1.24%。掺氮有序多孔TiO2微球的光催化性能好于未掺氮TiO2的光催化性能。     

纳米尺度PS/Ag核壳结构复合球的制备与表征

采用分步法制备了聚苯乙烯/银(PS/Ag)核壳结构复合纳米球。首先采用无皂乳液聚合法并利用丙烯酸(AA)的羧基对制备的PS球进行改性,使其表面带负电荷;然后通过静电吸附作用在改性PS球的表面沉积[Ag(NH3)2]+,水浴(80℃)环境中利用十二烷基磺酸钠(SDS)作为还原剂将PS球表面的[Ag(NH3)2]+还原,制备出PS/Ag核壳结构复合球。通过动态激光粒度分析仪和透射电子显微镜对PS/Ag核壳纳米球的粒度分布、形貌和结构进行了表征,研究了AA的用量对复合球粒径及包覆的Ag壳厚度的影响。结果表明,随着AA用量的增大,所包覆的银层更加致密,厚度增大,当AA用量为15%时可得到Ag完全包覆的PS/Ag复合纳米球。     

TiO2@SiO2微球的制备及其光催化性能研究

采用模板法以钛酸丁酯为钛源,SiO2为模板球,制备出了TiO2包覆SiO2微球。利用SEM、TEM、XRD、EDS对样品形貌、结构和成分进行了表征分析,并测试了样品的光催化性能。结果表明TiO2@SiO2微球的光催化性能优于用相同方法制得的TiO2的光催化性能,当使用TiO2@SiO2微球为光催化剂时,在光照180min后甲基橙的降解率达到82%,而相同方法制得的TiO2为56%,较后者提高了26%,具有良好的光催化活性。     

煅烧温度对TiO_2中空微球光催化性能的影响

以分散聚合法制得的单分散阳离子聚苯乙烯（PS）微球为模板,钛酸丁酯为前驱体,采用溶胶-凝胶法在模板表面包覆TiO2壳层,并在不同煅烧温度下制备了晶相结构不同的微米级中空TiO2微球。采用TEM、SEM、FT-IR、XRD、UV-Vis DRS对样品的微观结构、相态组成及光催化性能进行了表征。结果表明TiO2中空微球平均粒径达到1.23μm,壳层厚度约为30nm;随着煅烧温度增加,锐钛矿晶粒尺寸会增加,并在700℃时出现混晶结构;在500℃煅烧得到的TiO2中空微球对甲基橙（MO）降解表现出比P25更好的光催化性能及光催化稳定性。     

胶晶模板法制备WO3多孔薄膜及其光催化特性

通过苯乙烯聚合制备了聚苯乙烯微球胶体,采用浸渍-提拉制备成为紧密堆积的PS球胶晶模板,微球之间的间隙采用溶胶-凝胶法制备的WO3溶胶填隙,最后通过煅烧得到有序规则排列的多孔WO3薄膜。通过XRD、SEM对WO3多孔薄膜的结构及形貌进行了表征,并评价了薄膜的光催化性能。结果表明,在450℃高温下煅烧PS模板,得到有序排列的多孔WO3薄膜,平均粒径为150nm,光催化效率最高。     

载银SnO2复合微球的制备及表征

以结晶四氯化锡(SnCl4·5H2O)和尿素为原料,采用溶剂热法在180℃下反应12h制备出了单分散性良好的SnO2微球,并通过原位化学还原法在SnO2微球表面沉积银纳米颗粒制备表面载银的SnO2复合微球。考察了表面活性剂的种类及SnCl4·5H2O的浓度对微球形貌的影响,分析了Ag纳米颗粒在微球表面分布的均匀性。通过XRD、SEM、EDS、TEM等分析手段对产物进行了表征。结果表明,以PEG6000为模板导向剂,SnCl4浓度为2mmol时,可以得到分散性良好、直径约为1μm的SnO2微球,微球由平均晶粒尺寸约为5nm的SnO2纳米晶粒组装而成;以Sn2+活化处理SnO2微球,弱还原剂聚乙烯吡咯烷酮(PVP)还原Ag+,可以得到Ag纳米颗粒均匀沉积的载银SnO2复合微球。     

A facile method for fabrication of highly ordered hollow Ag/TiO2 nanostructure and its photocatalytic activity

This letter reports a facile and efficient strategy for the designed preparation of highly ordered hollow Ag/TiO₂ nanostructure. Different from previous reports, the presently proposed method conveniently combines the long-range ordering porosity and the property of Ag nanoparticles by a general colloidal crystal-templating technique. The sample was characterized by SEM and XRD. The results show that such hollow nanostructured material is composed of anatase TiO₂ and metal Ag. The as-prepared sample shows a good photocatalytic activity for photodegradation of methyl orange compared with the reference samples, which was attributed to its long-range ordering porosity and the addition of Ag nanoparticles.     

Preparation and enhanced photocatalytic performance of Sn ion modified titania hollow spheres

Sn-doped hollow titania spheres were prepared using carbon spheres as template and Sn-doped titania nanoparticles as building blocks. The Sn-doped titania nanoparticles were synthesized under mild condition (low temperature and atmospheric pressure). The prepared hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The effects of Sn content on the physical structure and photocatalytic activity of doped hollow titania sphere samples were investigated. It shows that the increasing of Sn content induces the transformation of titania from anatase to rutile phase. Results also showed that there was an optimal Sn-doped content (5%) in our samples for the photocatalytic degradation of Reactive Brilliant Red X-3B (C.I. reactive red 2).     

Synthesis and photo-degradation application of WO3/TiO2 hollow spheres

A WO(3)/TiO(2) composite, hollow-sphere photocatalyst with average diameter of 320 nm and shell thickness of 50 nm was successfully prepared using a template method. UV-vis diffuse reflectance spectra illustrated that the main absorption edges of the WO(3)/TiO(2) hollow spheres were red-shifted compared to the TiO(2) hollow spheres, indicating an extension of light absorption into the visible region of the composite photocatalyst. The WO(3) and TiO(2) phases were confirmed by X-ray diffraction analysis. BET isotherms revealed that the specific surface area and average pore diameter of the hollow spheres were 40.95 m(2)/g and 19 nm, respectively. Photocatalytic experiments indicate that 78% MB was degraded by WO(3)/TiO(2) hollow spheres under visible light within 80 min. Under the same conditions, only 24% MB can be photodegraded by TiO(2). The photocatalytic mineralization of MB, catalyzed by TiO(2) and WO(3)/TiO(2), proceeded at a significantly higher rate under UV irradiation than that under visible light, and more significant was the increase in the apparent rate constant with the WO(3)/TiO(2) composite semiconductor material which was 3.2- and 3.5-fold higher than with the TiO(2) material under both UV and visible light irradiation. The increased photocatalytic activity of the coupled nanocomposites was attributed to photoelectron/hole separation efficiency and the extension of the wavelength range of photoexcitation.     

Synthesis,characterization, antibacterial and photocatalytic performance of Ag/AgI/TiO2 hollow sphere composites

Dispersed TiO₂ hollow spheres were successfully prepared which was obtained via Ostwald ripening under solvothermal conditions without any templates or surfactants. Then, the AgI/TiO₂ was synthesized by the deposition−precipitation process. Finally, Ag/AgI/TiO₂ was obtained by a photocatalytic reduction way. Their characteristics were analyzed by XRD, SEM, HRTEM, N₂ adsorption−desorption measurements and UV-vis absorption spectra. To demonstrate the potential applications of such composites, their antibacterial activity against Escherichia coli (E. coli) was studied by microcalorimetry for the first time, and their photocatalytic performance for degradation of different organic dyes under simulated UV and visible light was discussed. The results indicated that Ag/AgI/TiO₂ hollow spheres revealed elevated antibacterial and photocatalytic activity because of their unique morphology, hollow structure and high surface area. The mechanism of the excellent antibacterial and photocatalytic activity of Ag/AgI/TiO₂ hollow spheres are discussed which are attributed to the synergetic effect of Ag, AgI and TiO₂. It suggested that the new Ag/AgI/TiO₂ photocatalyst has broad application prospects in solar cell, sensor, antibacterial, catalysis and nanotechnology.     

Facile synthesis of Ag nanoparticles supported on TiO2 inverse opal with enhanced visible-light photocatalytic activity

TiO₂ inverse opal films loaded with silver nanoparticles (ATIO) were synthesized on glass substrates. TiO₂ inverse opal (TIO) films were prepared via a sol-gel process using self-assembly of SiO₂ colloidal crystal template and a facile wet chemical route featuring an AgNO₃ precursor solution to fabricate silver nanoparticles on the TIO films. The inverse opal structure and Ag deposition physically and chemically modify titania, respectively. The catalysts were characterized by Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), UV-vis absorption spectra, X-ray photoelectron spectroscopy and photoluminescence spectroscopy. The HRTEM results show that Ag nanoparticles measuring 5-10 nm were evenly distributed on TIO. Both the UV- and visible-light photocatalytic activities of the samples were evaluated by analyzing the degradation of methylene blue (MB) in aqueous solution. The results reveal that the apparent reaction rate constant (k_app) of MB degradation of the sample ATIO under UV-light irradiation is approximately 1.5 times that of the conventional Ag-loaded TiO₂ film (ATF) without an ordered porous structure at an AgNO₃ concentration of 5 mM in the precursor solution. At an AgNO₃ concentration of 10 mM, the sample exhibits a k_app value approximately 4.2 times that of ATF under visible-light irradiation. This enhanced visible-light photocatalytic performance can be attributed to the synergistic effect of optimized Ag nanoparticle deposition and an ordered macroporous TIO structure. Repeated cycling tests revealed that the samples showed stable photocatalytic activity, even after six repeated cycles.     

Bi_2MoO_6空心球的水热沉淀法制备及其光催化性能

以葡萄糖为前躯体,采用水热法制备胶体碳球,以其为模板通过水热沉淀法制备C/Bi2MoO6核壳结构,然后在350℃空气中煅烧,获得了具有良好光催化性能的Bi2MoO6空心球.通过SEM、XRD、FT-IR和BET等测试方法对该催化剂进行了表征;并对其形成机理及反应过程进行了初步探讨,以亚甲基蓝作为被降解物质,研究了其光催化活性。结果表明,Bi2MoO6空心球是由纳米晶粒组成的,壁厚约为30～50nm,平均直径约为0.6～0.8μm,采用胶体碳球作模板时制得的Bi2MoO6空心球比表面积为11.315m2/g,而直接合成的粉体比表面积为3.378m2/g。在黑管灯照射下,2.5h亚甲基蓝的降解率达到了91.95%。     

有序多孔结构二氧化钛薄膜的制备和应用

本文探讨了一种制备二氧化钛高度有序多孔结构的方法及其在染料敏化太阳电池中的应用。采用聚苯乙烯悬浮液,采取垂直沉积法得到了聚苯乙烯胶体晶体;以该模板制备了高度有序的纳米二氧化钛反蛋白石多孔薄膜。对胶体晶体模板和二氧化钛反蛋白石有序膜的微观结构进行表征和讨论。用所制得的二氧化钛反蛋白石有序膜组装成染料敏化太阳电池。通过电流...     

Synthesis and photocatalytic oxidation properties of titania hollow spheres

The hollow spheres of anatase TiO₂ with higher photocatalytic activity have been fabricated by spherical CaCO₃ nanoparticles as a template, and titanium sulfate (Ti(SO₄)₂) as a precursor, and the CaCO₃ templates were dissolved subsequently in dilute HNO₃ solution. The TiO₂ hollow spheres samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and N₂ adsorption-desorption isotherms. The characterization results indicate that as prepared TiO₂ hollow spheres sample was transformed to anatase phase in calcined at 400 °C, and the anatase TiO₂ hollow spheres have a higher specific surface area and show much better photocatalytic activity than commercial P25 in the photodegradation of Rhodamine B under the UV irradiation.