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71.
Multiporous TiO2/Ti film electrodes were prepared by different anodic oxidation processes at low voltage, in which the micro-structured TiO2 thick films were prepared in H2SO4–H2O2–H3PO4–HF solution for 2 h and the nano-structured TiO2 thin films were prepared in H3PO4–HF solution for 30 min with post-calcination. Both types of TiO2/Ti films were characterized by scanning electron microscopy and X-ray diffraction analysis. The photocatalytic (PC) and photoelectrocatalytic (PEC) reactivity of the TiO2/Ti electrodes were evaluated in terms of bisphenol A (BPA) degradation in aqueous solution. The experimental results demonstrated that the nano-structured TiO2/Ti thin-film electrodes had higher reactivity in the BPA degradation reaction. The PEC degradation of BPA was further studied using different cathodes, either a reticulated vitreous carbon (RVC) electrode or a platinum (Pt) electrode. The experimental results confirmed that the efficiency of BPA degradation could be significantly enhanced in the TiO2/Ti–RVC reaction system due to the generation of H2O2 on the RVC cathode. It is believed that such a H2O2-assisted TiO2 PEC oxidation process may have good potential for water and wastewater treatment. 相似文献
72.
Hideki Koyama 《Journal of Applied Electrochemistry》2006,36(9):999-1003
Dilute HF solutions with concentrations down to 0.03% have been used to obtain luminescent porous silicon (PSi) layers on p-type Si wafers. The experimental results show that with a constant etching time of 30 min, PSi layers with sufficient luminescence efficiencies can be formed for HF concentrations as low as 0.1%. Because of a significantly lowered critical current density, only very low etching current densities of ≤0.1 mA cm−2 can result in the formation of luminescent PSi samples in 0.1% HF solutions. A notable result is that these low etching current densities cannot be used to form luminescent PSi layers in concentrated ( ≥1%) HF solutions. The behavior of PL intensity as a function of etching current density has been analyzed over a wide range of HF concentration. The PL intensity is determined by the ratio of the etching current density to the critical current density, suggesting that the presence of silicon oxides plays an important role in the formation of luminescent Si nanostructures in PSi layers. 相似文献
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75.
《Journal of Experimental Nanoscience》2013,8(3):207-214
A fabrication method for one-step anodization of an anodic aluminum oxide (AAO) template with nanopore arrays using pretreated high purity aluminum foil is reported in this article. Morphology of the AAO was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results showed that porous AAO with ideal nanopore arrays can be fabricated by one-step anodization fabrication technology on high purity aluminum foil which had been anodized at 45?V direct current (DC), in 0°C, 0.5?M H2C2O4 solution for 48 hours. The average pore diameter and the interpore distance were 80?nm and 120?nm, respectively. Nanopores in porous AAO had very narrow size distribution and were arranged into hexagonal array. The formation mechanism of nanopore arrays in porous AAO is discussed. Porous AAO with ideal nanopore arrays provide an ideal template for preparation of many one-dimensional nanomaterials. One-step anodization of AAO is a simpler procedure and more applicable in industrial application than the previous two-step anodization technology. 相似文献
76.
A novel interfacial structure consisting of long (up to 5 μm), thin (about 300 nm), highly-ordered, free-standing, highly-reproducible aluminum oxide nanobottles and long tubular nanocapsules attached to a rigid, thin (less than 1 μm) nanoporous anodic alumina membrane is fabricated by simple, fast, catalyst-free, environmentally friendly voltage-pulse anodization. A growth mechanism is proposed based on the formation of straight channels in alumina membrane by anodization, followed by neck formation due to a sophisticated voltage control during the process. This process can be used for the fabrication of alumina nanocontainers with highly controllable geometrical size and volume, vitally important for various applications such as material and energy storage, targeted drug and diagnostic agent delivery, controlled drug and active agent release, gene and biomolecule reservoirs, micro-biologically protected platforms, nano-bioreactors, tissue engineering and hydrogen storage. 相似文献
77.
本研究采用剧烈-温和阳极氧化(hard anodization-mild anodization, HA-MA)结合快速制备高度有序多孔阳极氧化铝(porous anodic alumina, PAA)膜的方法, 即先利用HA在铝表面快速形成有序凹坑阵列, 然后再对表面留有有序凹坑的铝基进行温和阳极氧化, 制备出有序PAA膜。研究了剧烈阳极氧化时氧化电压、氧化时间对所制备PAA膜有序度的影响。研究结果表明, HA-MA结合法制备PAA膜的优化HA参数为: 0.3 mol/L硫酸、80 V、10 min。HA-MA结合法所制备PAA膜的有序性和机械稳定性与二步温和阳极氧化法的相近, 但形成有序PAA膜所需的时间为4.5 h, 约为温和阳极氧化法的1/4, 极大地提高了高度有序PAA膜的制备效率。 相似文献
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79.
We evaluated the scanning probe microscope based anodization process of silicon(100) terminated by organic monolayers of the same thickness but with different surface properties. The surface energy of these monolayers with its dispersive and polar component was determined by contact angle measurements. We discovered that the anodization oxide characteristics depend ceteris paribus clearly on the surface properties of the sample. With an increased polar component, and therefore hydrophilic character of the surface, the formed oxide structures became broader and thinner. On the other hand a hydrophilic surface allowed the generation of oxide structures at higher tip velocities and lower applied voltages. The absolute amount of formed oxide is independent of the monolayer indicating a dominating influence of initially formed oxide on the following oxidation process. 相似文献
80.
Yip CT Huang H Zhou L Xie K Wang Y Feng T Li J Tam WY 《Advanced materials (Deerfield Beach, Fla.)》2011,23(47):5624-5628
A TiO(2) nanotube layer with a periodic structure is used as a photonic crystal to greatly enhance light harvesting in TiO(2) nanotube-based dye-sensitized solar cells. Such a tube-on-tube structure fabricated by a single-step approach facilitates good physical contact, easy electrolyte infiltration, and efficient charge transport. An increase of over 50% in power conversion efficiency is obtained in comparison to reference cells without a photonic crystal layer (under similar total thickness and dye loading). 相似文献