TiO2/SnO2复合空心球在染料敏化太阳能电池中的应用

采用模板辅助法制备了SnO2/TiO2复合空心球,样品直径为1.5~4.0μm,比表面积达到了92.9 m^2·g^-1,复合空心球表现出优越的光散射性能.以这种复合空心球作为染料敏化太阳能电池的光阳极,电池的光电转换效率可达到7.72%,高于SnO2微米球(2.70%)和TiO2微米球(6.26%).此外,以锐钛矿型TiO2纳米晶作为底层,SnO2/TiO2复合空心球作为光散射层制备的双层结构光阳极,电池光电转换效率进一步提升至8.43%.     

利用胶体碳球为模板制备SiO2、TiO2、SnO2空心球

介观尺度的氧化物空心球材料在许多领域都有着潜在的应用价值[1],因此近年来受到人们的广泛关注。其制备方法包括:模板法[2],声化学法[3],水热法[4]等。其中胶体粒子模板合成是制备氧化物空心球材料的一条最为有效的途径。常见的胶体粒子有金、银、CdS的纳米粒子,介观尺度的SiO     

Preparation and properties of Nafion/hollow silica spheres composite membranes

In present work, hollow silica spheres (HSS)/Nafion^® composite membranes were prepared by solution casting. The thermal properties, water retention, swelling behavior and proton conductivity of the composite membranes were explored. It was found that HSS dispersed well at micrometer scale in the obtained composite membranes by SEM and TEM observation. Thermal properties of composite membranes were improved than that of recast Nafion^® membrane. Compared with the recast Nafion^® membrane, the composite membranes showed higher water uptake and lower swelling degree at the temperature range from 40 to 100 °C. At the same HSS loading, the smaller the diameter of HSS in composite membranes, the more the water uptake, however, the swelling degree of composite membranes was increased. The proton conductivity of the composite membrane with 3–5 wt.% HSS (120 and 250 nm) increased distinctively at above 60 °C, reached the optimal value at 100 °C, and decreased slowly when the temperature exceeded 100 °C.     

Preparation and characterization of hollow spheres of rutile

Hollow spherical particles of rutile were obtained by coating colloidal polystyrene beads with a titanium oxide hydrate layer and subsequently calcining at elevated temperatures under an oxygen atmosphere. In order to investigate the optimum conditions for the preparation of these hollow beads the maximum temperature and heating rate were systematically varied. The dimensions of the voids and the shell thickness of the hollow beads can be tailored by the size of the polystyrene beads and the thickness of the inorganic layer, respectively.     

Large-scale fabrication of TiO2 hierarchical hollow spheres

In this Communication, we report the fabrication of well-crystallized rutile-phase TiO2 hollow spheres using potassium titanium oxalate as the precursor. The spheres exhibited unique three-dimensional hierarchical architectures and demonstrated a significantly improved photocatalytic performance. The synthetic strategy used in this process represents a general approach and therefore may contribute to the formation mechanisms of hollow nanostructures.     

Preparation and characterization of CoFe2O4/TiO2 magnetic composite films

CoFe₂O₄/TiO₂ magnetic composite films were prepared using the sol-gel method with tetrabutyltitanate and metallic chlorates as starting materials. The effects of heat treatment temperatures on microstructures and on magnetic properties were studied. The microstructure and properties of the samples at different heat treatment temperatures were characterized by X-ray diffraction, Raman spectrum, scanning electron microscopy, polarized microscopy and vibrating sample magnetometry. The results show that crystals of different substances grow up independently. Cobalt ferrite is evenly embedded into the titanium dioxide matrix in the prepared composite films. The magnetism of the composite films is enhanced with an increase of the heat temperature.     

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.     

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%）.     

Porous carbon and carbon composite hollow spheres

In this communication, we propose a template approach toward synthesis of carbon hollow spheres by direct carbonization of highly crosslinked sulfonated polystyrene gel hollow spheres (sPS). The sulfonic acid group can facilitate carbonization. Moreover, the acid group can also induce a favorable growth of other materials within the sPS gel-forming carbon-based composite shell such as bi-continuous C/SiO₂ and their derivative ceramic SiC. Release of small molecules during polymers decomposition results porous shell.     

Double-shell structural polyaniline-derived TiO2 hollow spheres for enhanced photocatalytic activity

Transition Metal Chemistry - Polyaniline (PANI) is a conducting polymer which has been employed as a photosensitizer for enhancing the performance of a number of photocatalysts. Herein, we describe...     

Preparation and characterization of sulfonated polyimide/TiO2 composite membrane for vanadium redox flow battery

A sulfonated polyimide (SPI)/TiO₂ composite membrane was fabricated by a blend way to improve its performance in vanadium redox flow battery (VRB). Both EDS and XRD results verify the successful preparation of the SPI/TiO₂ composite membrane. The surface SEM image shows its homogeneous structure. TG analysis identifies its thermal stability. The SPI/TiO₂ composite membrane possesses much lower permeability of VO²⁺ ions (2.02?×?10^?7 cm² min^?1) and favorable proton conductivity (3.12?×?10^?2 S cm^?1). The VRB single cell with SPI/TiO₂ composite membrane shows higher coulombic efficiency (93.80–98.00 %) and energy efficiency (83.20–67.61 %) at the current density ranged from 20 to 80 mA cm^?2 compared with that with Nafion 117 membrane. And the operational stability of the as-prepared composite membrane is good after 50 times of cycling tests. Therefore, the low-cost SPI/TiO₂ composite membrane with excellent battery performance exhibits a great potential for application in VRB.     

复合光催化剂CeO2/TiO2的制备及性能研究

采用溶胶-凝胶-浸渍法制备了CeO2／TiO2二元复合纳米光催化剂,用XRD、FTIR等对其进行了表征。以紫外灯为光源,直接耐晒兰(DFB)的脱色为模型反应,研究了CeO2／TiO2的光催化活性。结果表明：掺杂摩尔百分比x(CeO2)=1．44％、600℃煅烧2h时,该催化剂的催化活性最高,比纯TiO2高近1倍。DFB脱色的最佳条件为：pH9．0～10．0,投加量200mg／50mL,空气流量200mL／min。     

Designing of nanostructured hollow TiO2 spheres obtained by ultrasonic spray pyrolysis

Theoretical model describing the mechanism of droplet formation and structure of hollow TiO2 spheres prepared by the process of ultrasonic spray pyrolysis, using colloidal solution consisting of the 2.5-nm TiO2 nanoparticles as a precursor, is developed. The proposed model quantitatively defines each line in the size distribution spectrum. The mechanism of droplet formation and/or particle genesis is fully determined by harmonization between the physical fields inherent to the system as the consequence of its physical characteristics: external, e.g., ultrasound, and internal. Agreement between theoretically obtained basic structural parameters (size distribution and geometry) and experimentally determined values was found.     

Synthesis and characterization of conductive polyaniline/TiO2 composite nanofibers

Fibrillar conductive polyaniline/TiO₂ (PANI/TiO₂) nanocomposites with different TiO₂ amount were synthesized with a template-free in situ polymerization method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and conductivity measurement. The morphology determination shows that the PANI/TiO₂ composite nanofibers are relatively uniform with the diameter and length in the range of 20–40 nm and 390–420 nm respectively. It also shows that the TiO₂ of the composite is rutile crystalline and PANI has some degree of crystallinity. The IR measurement indicates that there is a strong interaction between the PANI and TiO₂ nanoparticles, and it has a beneficial effect on the thermal stability of the composite nanofiber. The conductivity of PANI/TiO₂ composites changes with TiO₂ amount and reaches an optimum value of 2.86 S/cm at 11.1 wt% TiO₂. Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(4): 67–70 (in Chinese)     

碳纳米管/TiO_2复合材料的制备及表征研究

采用溶胶-凝胶法和水热合成法,制备出碳纳米管/TiO2(CNTs/TiO2)复合材料。通过X-射线衍射仪(XRD)、扫描电子显微镜(SEM),紫外-可见漫反射光谱(UV-Vis),荧光光谱(LS)检测CNTs/TiO2的晶型及形貌。结果表明:锐钛矿相TiO2纳米颗粒负载在碳纳米管的管壁上,CNTs/TiO2在紫外-可见光波长范围均有较好的吸收性能。在灭菌灯照射下,以甲基橙溶液为降解目标,CNTs/TiO2复合材料对甲基橙溶液的降解有高的光催化活性,180 min内降解率达到85%以上。     

Polyaniline/Au composite hollow spheres: synthesis, characterization, and application to the detection of dopamine

Polyaniline (PANI)/Au composite hollow spheres were successfully synthesized using polystyrene/sulfonated polystyrene core/shell gel particle templates. The PANI shell thickness and the number of Au nanoparticles decorating the PANI could be controlled effectively by adjusting the experimental conditions. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres. Furthermore, PANI/Au composites were immobilized on the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI/Au-modified GCEs showed one pair of redox peaks and high catalytic activity for the oxidation of dopamine. The possible formation mechanism of the PANI/Au composite hollow spheres was also discussed.     

Preparation and properties of polysulfone/TiO2 composite ultrafiltration membranes

The influence of inorganic filler TiO₂ nanoparticles on the morphology and properties of polysulfone (PS) ultrafiltration membranes was investigated. PS/TiO₂ composite membranes were prepared by a phase‐inversion method. TiO₂ nanoparticles modified by sodium dodecyl sulfate were uniformly dispersed in an 18 wt % PS casting solution. The addition of TiO₂ resulted in an increase in the pore density and porosity of the membrane skin layer. The pore size distribution changed from the log‐normal distribution to the bimodal distribution because of the presence of TiO₂ nanoparticles, and some large pores were observed when the concentration of the filler was over 3 wt %. The skin layer was gradually thickened; meanwhile, the morphology sublayer changed from macrovoids to spongelike pores, in comparison with PS membranes without the filler. The addition of TiO₂ also induced increases in the hydrophilicity, mechanical strength, and thermal stability. The ultrafiltration experiments showed when the concentration of TiO₂ was less than 2 wt %, the permeability and rejection of the membrane was enhanced and then decreased drastically with a higher filler concentration (>3%). © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 879–887, 2006     

TiO2 and SnO2@TiO2 hollow spheres assembled from anatase TiO2 nanosheets with enhanced lithium storage properties

TiO(2) and SnO(2)@TiO(2) hollow spheres assembled from anatase TiO(2) nanosheets with exposed (001) high-energy facets are constructed via a templating approach, and the as-prepared samples exhibit enhanced lithium storage properties.