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31.
S.‐Z. Chu K. Wada S. Inoue M. Isogai A. Yasumori 《Advanced materials (Deerfield Beach, Fla.)》2005,17(17)
A simple, low‐cost approach to fabricating large‐area highly ordered nanoporous alumina films in sulfuric acid solutions through a single‐step high‐field anodization, without the assistance of any additional process, is reported on p. 2115 by Chu and co‐workers. The critical high anodizing potential in the adopted electrolyte system increases with the ageing of solutions after a long period of anodization. Correspondingly, the applicable current density for stable anodization rises significantly, thus leading to high‐speed film growth. Uniform porous anodic alumina films in sulfuric acid solutions under a high electric field of 40–70 V and 1600–2000 A m–2 are achieved. 相似文献
32.
CeF3 nanoparticles 5-10 nm in size were prepared using the polyol method. CeCl3 and HF were heated up in ethylene glycol. At a temperature of 180 °C crystalline CeF3 nanoparticles were formed. The material was washed with ethanol, centrifugated and dried. The particles were characterized by EDX, XRD and TEM. 相似文献
33.
ZnS nanoparticles about 3 nm in size were prepared by a simple, rapid and reliable route under microwave irradiation in a heterogeneous system, using ZnAc2·2H2O (AcCH3COO) and Na2S·9H2O as the starting materials, ethylene glycol (EG) as the medium. The product was characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and ED, respectively. The optical properties of ZnS nanoparticles were studied. 相似文献
34.
Nanocomposite tantalum carbide/amorphous hydrocarbon (TaC/a-C:H) thin film composition, structure, and mechanical properties depend on the direct current bias voltage (Vb) level applied to the substrate during reactive sputter deposition. A set of TaC/a-C:H films was deposited across the range Vb = 0 to − 300 V with all other deposition parameters held constant except substrate temperature, which was allowed to reach its steady state during the depositions. Effects of Vb on film composition and structure were explored, including TaC crystallite size and dispersion using X-ray diffraction and high resolution transmission electron microscopy. In addition, the dependency of stress and hardness on Vb was studied with an emphasis on relationships to a-C:H phase structure. 相似文献
35.
Well-crystalline Al4B2O9 nanorods were synthesized by a low-heating-temperature solid-state precursor method. This process does not involve the use of metal catalyst or protective gas. The products were characterized by thermogravimetry and differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed the products to possess a single phase, large surface area, narrow size distribution of 20-30 nm and lengths up to several micrometers. A self-catalytic growth mechanism of the aluminum borate nanorods is proposed. 相似文献
36.
Birnessite-type MnO2 nanoparticles are synthesized by mixing KMnO4 solution directly with ethylene glycol under ambient conditions. When cobalt exists in the solution, the micro-morphology of the products transforms from conglomeration to dispersive state. The result of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) shows that the product is constructed with nanosphere in sizes of ca. 40 nm. These nanospheres are twisted by nanorods clusters. X-ray diffraction (XRD) pattern shows that the products are birnessite-type. The electrochemical properties of the prepared materials are studied using cyclic voltammetry (CV) and galvanostatic charge–discharge test in aqueous electrolyte. The product shows a very high specific capacity of 326.4 F g−1. These results indicate that cobalt has great effects on the micro-morphology and electrochemical properties of manganese dioxide. 相似文献
37.
Sakdinun Nuntang Sirilux Poompradub Suchada Butnark Toshiyuki Yokoi Takashi Tatsumi Chawalit Ngamcharussrivichai 《Materials Chemistry and Physics》2014
This study is the first report on synthesis, characterization and catalytic application of propylsulfonic acid-functionalized mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). In comparison with propylsulfonic acid-functionalized HMS (HMS-SO3H), a series of NR/HMS-SO3H composites were prepared via an in situ sol–gel process using tetrahydrofuran as the synthesis media. Tetraethylorthosilicate as the silica source, was simultaneously condensed with 3-mercaptopropyltrimethoxysilane in a solution of NR followed by oxidation with hydrogen peroxide to achieve the mesoporous composites containing propylsulfonic acid groups. Fourier-transform infrared spectroscopy and 29Si MAS nuclear magnetic resonance spectroscopy results verified that the silica surfaces of the NR/HMS-SO3H composites were functionalized with propylsulfonic acid groups and covered with NR molecules. After the incorporation of NR and organo-functional group into HMS, the hexagonal mesostructure remained intact concomitantly with an increased framework wall thickness and unit cell size, as evidenced by the X-ray powder diffraction analysis. Scanning electron microscopy analysis indicated a high interparticle porosity of NR/HMS-SO3H composites. The textural properties of NR/HMS-SO3H were affected by the amount of MPTMS loading to a smaller extent than that of HMS-SO3H. NR/HMS-SO3H exhibited higher hydrophobicity than HMS-SO3H, as revealed by H2O adsorption–desorption measurements. Moreover, the NR/HMS-SO3H catalysts possessed a superior specific activity to HMS-SO3H in the esterification of lauric acid with ethanol, resulting in a higher conversion level. 相似文献
38.
Hematite solid spindles and hollow spindles have been selectively synthesized by a template-free, economical hydrothermal method, using FeCl3·6H2O as the starting materials and NaOH as the homogeneous precipitant. XRD analyses indicated that the products consisted of α-Fe2O3. SEM and TEM measurements showed that the morphologies of products were in the shape of solid spindles and hollow spindles, respectively. A possible formation process based on the nucleation-oriented aggregation-recrystallization mechanism is proposed. Moreover, the as-prepared hollow spindle-like α-Fe2O3 exhibits a good response and reversibility to some organic gas, such as 2-propanol and acetone. Compared with other hematite nanostructures, the porous hollow hematite spindles show outstanding performance in gas sensing due to their large surface area and porous hollow structure. Because of the unique porous hollow structures of the samples, the photocatalytic property of the spindle-like α-Fe2O3 was also investigated. 相似文献
39.
Wenshuang Zhang Xinyong Li Qidong Zhao Yang Hou Yu Shen Guohua Chen 《Materials Chemistry and Physics》2011
Uniform α-Fe2O3 nanotubes with small aspect ratio were successfully fabricated by a hydrothermal method. In situ Fourier-transform infrared spectroscopy was used to study the mechanistic details of adsorption and photocatalytic oxidation of naphthalene over theα-Fe2O3 nanotubes. A possible degradation mechanism of naphthalene was proposed. 相似文献
40.
Colorless and organo-soluble polyimide (PI) films have been synthesized from an alicyclic dianhydride BCDA and aromatic diamine 3,4′-ODA in the cosolvent of DMAc and GBL via one-step process. The graphene oxide (GO) was mixed with the above PI in DMAc solution to fabricate the PI/GO nanocomposite films. With the addition of only 0.001 wt% of GO in PI matrix, the resultant nanocomposite (PI/GO-0.001) exhibits not only the enhanced resistance to moisture but also retains superior visible light transmission, enhanced mechanical strength, and excellent dimensional stability, simultaneously. The water-vapor-transmission-rate (WVTR) significantly reduced to 30 g mil m−2 day−1 for this nanocomposite compared to 181 g mil m−2 day−1 for pure PI. Notably, the PI/GO-0.001 nanocomposite also exhibits low coefficient of thermal expansion (CTE) of 41 ppm °C−1, which is benefited from the homogeneous distribution of ultrathin GO nanosheets in PI matrix. 相似文献