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Sample records for anodically oxidized titanium

  1. Fabrication of titanium oxide nanotube arrays by anodic oxidation

    Science.gov (United States)

    Zhao, Jianling; Wang, Xiaohui; Chen, Renzheng; Li, Longtu

    2005-06-01

    The formation of titanium oxide nanotube arrays on titanium substrates was investigated in HF electrolytes. Under optimized electrolyte and oxidation conditions, well-ordered nanotubes of titania were fabricated. Topologies of the anodized titanium change remarkably along with the changing of applied voltages, electrolyte concentration and oxidation time. Electrochemical determination and scanning electron microscope indicate the nanotubes are formed due to the competition of titania formation and dissolution under the assistance of electric field. A possible growth mechanism has also been presented.

  2. Synthesis and characterization of anodized titanium-oxide nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Michael Z. [ORNL; Lai, Peng [University of Cincinnati; Bhuiyan, Md S [ORNL; Tsouris, Costas [ORNL; Gu, Baohua [ORNL; Paranthaman, Mariappan Parans [ORNL; Gabitto, Jorge [Prairie View A& M University; Harrison, L. D. [Prairie View A& M University

    2009-01-01

    Anodized titanium-oxide containing highly ordered, vertically oriented TiO2 nanotube arrays is a nanomaterial architecture that shows promise for diverse applications. In this paper, an anodization synthesis using HF-free aqueous solution is described. The anodized TiO2 film samples (amorphous, anatase, and rutile) on titanium foils were characterized with scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Additional characterization in terms of photocurrent generated by an anode consisting of a titanium foil coated by TiO2 nanotubes was performed using an electrochemical cell. A platinum cathode was used in the electrochemical cell. Results were analyzed in terms of the efficiency of the current generated, defined as the ratio of the difference between the electrical energy output and the electrical energy input divided by the input radiation energy, with the goal of determining which phase of TiO2 nanotubes leads to more efficient hydrogen production. It was determined that the anatase crystalline structure converts light into current more efficiently and is therefore a better photocatalytic material for hydrogen production via photoelectrochemical splitting of water.

  3. Synthesis of self-ordered titanium oxide nanotubes by anodization of titanium

    Science.gov (United States)

    Krishnan, A. Yaadhav; Sivabalan, S.; Subhachandhar, S.; Balakrishnan, M.; Narayanan, R.

    2012-07-01

    Self-ordered arrays of titanium oxide nanotubes were prepared by anodization of Ti in sodium sulphate solution containing sodium fluoride. The dimensions of the nanotubes (diameter: 20-100 nm and length: 1000-1500 nm) could be tuned by changing the synthesis parameters. The as-anodized nanotubes showed amorphous structure which upon annealing at 500°C in oxygen atmosphere turned crystalline, according to XRD analysis. The pit morphologies show that pit initiation occurs due to NaF content in the electrolyte and nanotube formation starts after pit growth terminates.

  4. Preparation of bioactive titania films on titanium metal via anodic oxidation.

    Science.gov (United States)

    Cui, X; Kim, H-M; Kawashita, M; Wang, L; Xiong, T; Kokubo, T; Nakamura, T

    2009-01-01

    To research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF). Titanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1 min at room temperature. Anodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H(2)SO(4) and Na(2)SO(4) electrolytes, while amorphous titania films were produced after anodizing in CH(3)COOH and H(3)PO(4) electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7d, but titanium metal with amorphous titania layers was not able to induce apatite formation. The resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.

  5. Bioactive titanium metal surfaces with antimicrobial properties prepared by anodic oxidation treatment

    Institute of Scientific and Technical Information of China (English)

    YUE ChongXia; YANG BangCheng; ZHANG XingDong

    2009-01-01

    In order to endow titanium metals with bioactivity and antimicrobial properties,titanium plates were subjected to anodic oxidation treatment in NaCI solutions in this study.The treated titanium metals could induce apatite formation in the fast calcification solution,and osteoblasts on the treated titanium surfaces proliferated well as those on the untreated titanium metal surfaces.The treated metals could inhibit S.aureus growth in the microbial culture experiments.It was assumed that Ti-OH groups and Ti-CI groups formed on the treated titanium surface were responsible for the bioactivity and antimicrobial properties of the metals.The anodic oxidation treatment was an effective way to prepare bioactive titanium surfaces with antimicrobial properties.

  6. Formation of crystalline TiO2 by anodic oxidation of titanium

    Institute of Scientific and Technical Information of China (English)

    Zixue Su; Linjie Zhang; Feilong Jiang; Maochun Hongn

    2013-01-01

    Formation of crystalline TiO2 (anatase) films by anodic oxidation of titanium foils in ethylene glycol (EG) based electrolytes at room temperature has been investigated. By varying the anodizing parameters such as the amounts of water and NH4F added, applied voltage and anodization time, anodic TiO2 films with different crystalline structures were obtained. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) characterizations were employed to determine the morphologies and crystalline structures of as-prepared anodic TiO2 films. The results indicate that crystallization of anodic TiO2 films was generally facilitated by high fluoride concentration, high applied voltage and longer anodization time, and the formation of anodic TiO2 films with best crystallinity could only be achieved when optimized amounts of water were added.

  7. The surface treatment on oxide film of pure titanium Part 1. The effect of Anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    Ge Wang; Xiangrong Cheng

    2006-01-01

    目的:研究阳极氧化对纯钛种植材料氧化膜的影响.方法:5片直径9 mm厚2 mm的纯钛在升压速度为7~8 v/min、电流密度≤10 mA/cm2的条件下分别进行阳极氧化处理,(A)10 v 10 min,(B)24 v 10 min,(C) 40 v 10 min,(D)24 v 40 min,(E) 24 v 2 h.用potentiostat仪检测以上样品在生理盐水和人造海水中的电化学行为.结果:以上样品的颜色呈:A蓝色,B淡黄色,C粉红色,D金黄色,E深黄色.随着电压的升高和作用时间的延长,2.55峰渐渐强化,2.34峰弱化.在生理盐水中,阳极氧化膜的开路电势稳定于0 mV,而自然氧化膜则很快从-50上升到-40 mV,极化电流比自然氧化膜的低100倍.在人造海水中,阳极氧化膜的开路电势稳定在-90 mV,自然氧化膜则从-480 mV快速上升到-310 mV,且活化电流明显高于阳极氧化膜.结论:阳极氧化膜的颜色可能和膜的厚度有关,而颜色对种植体上的修复体有影响,因此,金黄色被选为理想的颜色.2.55和2.34峰的变化规律尚无法解释.阳极氧化膜的稳定性和耐腐蚀性远远高于自然氧化膜.因此,阳极氧化法是一种提高纯钛氧化膜耐腐蚀性的好方法.%Objectives: To study the oxide film of pure titanium implant material treated by anodic oxidation. Methods: Five commercially pure (CP) titanium sheets (9mm in diameter and 2mm thick) were treated by the speed of 7-8 v/min of potential, the current density ≤10mA/cm2 to (A) 10v for 10min, (B) 24v for 10min, (C) 40v for 10min, (D) 24v for 40min, (E) 24v for 2hr in Kawahara's electrochemical solution. The electro-chemical behavior of anodic oxide film and natural oxide film was studied using a potentiostat. Results: The samples color changed from white to the following sequence blue, light gold, pink, media gold and dark gold. Along with potential and time going on, XRD patterns showed that the peak 2.55 strengthened, and peak 2.34 weakened. The voltage-time curve in physiological salt solution (PSS) showed

  8. Characterization and quantification of oxides generated by anodization on titanium for implantation purposes

    Science.gov (United States)

    Aloia Games, L.; Pastore, J.; Bouchet, A.; Ballarre, J.

    2011-12-01

    The use of titanium as implant material is widely known in the surgery field. The formation of natural or artificial compact and protective oxide is a convenient tool for metal protection and a good way to generate phosphate deposits to enhance biocompatibility and bone fixation with the existing tissue. The present work has the aim of superficially modify commercially pure titanium sheets used in orthopedics and odontology, with a potencistatic anodization process with an ammonium phosphate and ammonium fluoride solution as electrolyte. The objective is to generate titanium oxides doped with phosphorous on the surface, to promote bioactivity. The characterization and quantification of the generated deposits is presented as a starting point for the future application of these materials. The applied characterization methods are X ray diffraction, micro-Raman spectroscopy analysis for evaluating the chemical and phase composition on the modified surface and PDI image analysis techniques that allow the segmentation of SEM images and the measurement and quantification of the oxides generated by the anodization process. The samples with polished treated surface at 30V have the deposit of a phosphate rich thick layer covering almost all the surface and spherical-shaped titanium oxide crystals randomly placed (covering more than 20% of the surface area).

  9. Surface characteristics and electrochemical corrosion behavior of a pre-anodized microarc oxidation coating on titanium alloy.

    Science.gov (United States)

    Cui, W F; Jin, L; Zhou, L

    2013-10-01

    A porous bioactive titania coating on biomedical β titanium alloy was prepared by pre-anodization followed by micro arc oxidation technology. The effects of pre-anodization on the phase constituent, morphology and electrochemical corrosion behavior of the microarc oxidation coating were investigated. The results show that pre-anodization has less influence on the phase constituent and the surface morphology of the microarc oxidation coating, but improves the inner layer density of the microarc oxidation coating. The decrease of plasma discharge strength due to the presence of the pre-anodized oxide film contributes to the formation of the compact inner layer. The pre-anodized microarc oxidation coating effectively inhibits the penetration of the electrolyte in 0.9% NaCl solution and thus increases the corrosion resistance of the coated titanium alloy in physiological solution.

  10. Anodic oxidized nanotubular titanium implants enhance bone morphogenetic protein-2 delivery.

    Science.gov (United States)

    Bae, In-Ho; Yun, Kwi-Dug; Kim, Hyun-Seung; Jeong, Byung-Chul; Lim, Hyun-Pil; Park, Sang-Won; Lee, Kwang-Min; Lim, Young-Chai; Lee, Kyung-Ku; Yang, Yunzhi; Koh, Jeong-Tae

    2010-05-01

    Implant failure has been attributed to loosening of an implant from the host bone possibly due to poor osseointegration. One promising strategy for improving osseointegration is to develop a functional implant surface that promotes osteoblast differentiation. In this study, a titanium (Ti) surface was functionalized by an anodic oxidation process and was loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2). The following four groups of Ti surfaces were prepared: machined (M), anodized machined (MA), resorbable blast medium (RBM), and anodized RBM (RBMA). The surfaces were characterized by scanning electron microscopy and contact angle measurements. The results showed that a Ti oxide layer (TiO(2)) was observed in the anodized surfaces in the form of nanotubes, approximately 100 nm in diameter and 500 nm in length. The hydrophilic properties of the anodized surfaces were significantly improved. The adsorbed rhBMP-2 loaded on the nonanodized surfaces and lyophilized showed spherical particle morphology. However, the adsorbed rhBMP-2 showed a dispersed pattern over the anodized surfaces. The velocity of the rhBMP-2 released from the surfaces was measured to determine if the anodized surface can improve in delivery efficiency. The results showed that the release velocity of the rhBMP-2 from the anodized surfaces was sustained when compared with that of the nonanodized surfaces. In addition, the rhBMP-2 released from the surface was found to be bioactive according to the alkaline phosphatase activity and the level of calcium mineral deposition. These results suggest that the TiO(2) nanotubular structure formed by anodizing is a promising configuration for sustained rhBMP-2 delivery.

  11. Photocatalytic effect of anodic titanium oxide nanotubes on various cell culture media

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chun-Kang; Hu, Kan-Hung; Wang, Shing-Hoa [National Taiwan Ocean University, Center for Marine Bioenvironment and Biotechnology, Keelung (China); National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung (China); Hsu, Todd [National Taiwan Ocean University, Center for Marine Bioenvironment and Biotechnology, Keelung (China); National Taiwan Ocean University, Institute of Bioscience and Biotechnology, Keelung (China); Tsai, Huei-Ting [National Taiwan Ocean University, Institute of Bioscience and Biotechnology, Keelung (China); Chen, Chien-Chon [National United University, Department of Energy and Resources, Miaoli (China); Liu, Shiu-Mei [National Taiwan Ocean University, Center for Marine Bioenvironment and Biotechnology, Keelung (China); National Taiwan Ocean University, Institute of Marine Biology, Keelung (China); Lin, Tai-Yuan [National Taiwan Ocean University, Institute of Optoelectronic Sciences, Keelung (China); Chen, Chin-Hsing [National Chiao Tong University, Department of Applied Chemistry, Hsinchu (China)

    2011-02-15

    The use of titanium dioxide (TiO{sub 2}) in photodynamic therapy for the treatment of cancer cells has been proposed following studies of cultured cancer cells. In this work, an ordered channel array of anodic titanium oxide (ATO) was fabricated by anodizing titanium foil. The ATO layer of nanotubes with diameters of 100 nm was made in NH{sub 4}F electrolyte by anodization. The photocatalytic effect of ATO was examined on various culture media by ultraviolet A (UV-A) (366 nm) irradiation. After UV-A irradiation of the ATO layer, redox potential of Tris-HCl buffer (pH 7.5) and dilute acrylamide solution increased instantaneously. The redox potential of the serum-containing RPMI1640 medium also increased dramatically, while that of serum-containing MEM and DMEM media increased slightly. The UVA-induced high redox potential was correlated with the greater ability to break down plasmid DNA strands. These phenomena suggest that a culture medium, such as RPMI1640, with a greater ability to produce free radical may be associated with a stronger photocatalytic effect of ATO on cultured cancer cells reported previously. (orig.)

  12. The Microstructure and Capacitance Characterizations of Anodic Titanium Based Alloy Oxide Nanotube

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    Po Chun Chen

    2013-01-01

    Full Text Available This paper presents a simple anodization process to fabricate ordered nanotubes (NTs of titanium and its alloys (Ti-Mo and Ti-Ta. TiO2, MoO3, and Ta2O5 are high dielectric constant materials for ultracapacitor application. The anodic titanium oxide contains a compact layer on the NT film and a barrier layer under the NT film. However, the microstructure of oxide films formed by anodic Ti-Mo and Ti-Ta alloys contains six layers, including a continuous compact layer, a continuous partial porous layer, a porous layer, a net layer, an ordering NT film, and an ordering compact barrier layer. There are extra layers, which are a partial porous layer and a porous layer, not presented on the TiO2 NT film. In this paper, we fabricated very high surface area ordered nanotubes from Ti and its alloys. Based on the differences of alloys elements and compositions, we investigated and calculated the specific capacitance of these alloys oxide nanotubes.

  13. Modern Trends in Anodic Oxidation of Titanium Implant%钛种植体阳极氧化的研究

    Institute of Scientific and Technical Information of China (English)

    王婷婷; 王丽娜(综述); 范震(审校)

    2016-01-01

    如何对钛种植体进行表面改性,提高钛种植体表面物理性能、化学性能和生物性能一直是国内外学者研究的热点。钛表面阳极氧化技术可增加钛表面氧化膜厚度,增加表面粗糙度,增强耐腐蚀性和抗菌性,使钛表面着色。细胞黏附实验显示,经阳极氧化后的钛表面生物活性提高,骨结合能力增强。根据氧化条件的不同,阳极氧化又可以分为一般阳极氧化、微弧氧化、二氧化钛纳米管的形成。本文将对钛表面阳极氧化的研究进展做一综述。%Anodic oxidation is used for the surface treatment of commercial implants to improve their functional (physi-cal, chemical, and biological) properties for clinical success. The anodic oxidation technique on the titanium can increase the thickness of titanium surface oxidation film and the surface roughness, enhance the corrosion resistance and antimicro-bial properties, change the color of titanium surface. Cell adhesion experiments have shown that titanium surface is more bioactive for initial bone bonding after anodic oxidation. According to different oxidation conditions, anodic oxidation can be divided into general anodic oxidation, micro arc oxidation, the formation of titanium dioxide nanotubes. This article re-views the impact of titanium and titanium alloy anodic oxidation technology on dental implant.

  14. OBTENTION OF POROUS TITANIUM DIOXIDE COATINGS BY ANODIC OXIDATION FOR PHOTOCATALYTIC APPLICATIONS

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    Hernán D. Traid

    2016-03-01

    Full Text Available Titanium dioxide is one of the most used materials in heterogeneous photocatalysis process due its low cost, low toxicity and high photocatalytic activity. In the present work, porous TiO2 coatings are obtained by anodic oxidation, starting at constant current density and continuing at constant potential of 120 V in spark discharge conditions. After the oxidation, the coatings received a thermal treatment. The studied variable was the current density. The curves of current density and potential showed characteristics fluctuations of spark discharge. Micrographs of the oxides showed an average pore diameter of 100 nm. Diffractograms showed, in all cases, the presence of the anatase and rutile phases of TiO2, showing an increase of the rutile fraction when the current density was higher. The synthesized oxides showed favorable characteristics as potential materials for heterogeneous catalysis processes for water treatment.

  15. Electrochemical combustion of indigo at ternary oxide coated titanium anodes

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    María I. León

    2014-12-01

    Full Text Available The film of iridium and tin dioxides doped with antimony (IrO2-SnO2–Sb2O5 deposited on a Ti substrate (mesh obtained by Pechini method was used for the formation of ·OH radicals by water discharge. Detection of ·OH radicals was followed by the use of the N,N-dimethyl-p-nitrosoaniline (RNO as a spin trap. The electrode surface morphology and composition was characterized by SEM-EDS. The ternary oxide coating was used for the electrochemical combustion of indigo textile dye as a model organic compound in chloride medium. Bulk electrolyses were then carried out at different volumetric flow rates under galvanostatic conditions using a filter-press flow cell. The galvanostatic tests using RNO confirmed that Ti/IrO2-SnO2-Sb2O5 favor the hydroxyl radical formation at current densities between 5 and 7 mA cm-2, while at current density of 10 mA cm-2 the oxygen evolution reaction occurs. The indigo was totally decolorized and mineralized via reactive oxygen species, such as (·OH, H2O2, O3 and active chlorine formed in-situ at the Ti/IrO2-SnO2-Sb2O5 surface at volumetric flow rates between 0.1-0.4 L min-1 and at fixed current density of 7 mA cm-2. The mineralization of indigo carried out at 0.2 L min-1 achieved values of 100 %, with current efficiencies of 80 % and energy consumption of 1.78 KWh m-3.

  16. Cycle Life of Commercial Lithium-Ion Batteries with Lithium Titanium Oxide Anodes in Electric Vehicles

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    Xuebing Han

    2014-07-01

    Full Text Available The lithium titanium oxide (LTO anode is widely accepted as one of the best anodes for the future lithium ion batteries in electric vehicles (EVs, especially since its cycle life is very long. In this paper, three different commercial LTO cells from different manufacturers were studied in accelerated cycle life tests and their capacity fades were compared. The result indicates that under 55 °C, the LTO battery still shows a high capacity fade rate. The battery aging processes of all the commercial LTO cells clearly include two stages. Using the incremental capacity (IC analysis, it could be judged that in the first stage, the battery capacity decreases mainly due to the loss of anode material and the degradation rate is lower. In the second stage, the battery capacity decreases much faster, mainly due to the degradation of the cathode material. The result is important for the state of health (SOH estimation and remaining useful life (RUL prediction of battery management system (BMS for LTO batteries in EVs.

  17. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  18. Adhesive strength of medical polymer on anodic oxide nanostructures fabricated on biomedical β-type titanium alloy.

    Science.gov (United States)

    Hieda, Junko; Niinomi, Mitsuo; Nakai, Masaaki; Cho, Ken; Mohri, Tomoyoshi; Hanawa, Takao

    2014-03-01

    Anodic oxide nanostructures (nanopores and nanotubes) were fabricated on a biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr alloy (TNTZ), by anodization in order to improve the adhesive strength of a medical polymer, segmented polyurethane (SPU), to TNTZ. TNTZ was anodized in 1.0M H3PO4 solution with 0.5 mass% NaF using a direct-current power supply at a voltage of 20V. A nanoporous structure is formed on TNTZ in the first stage of anodization, and the formation of a nanotube structure occurs subsequently beneath the nanoporous structure. The nanostructures formed on TNTZ by anodization for less than 3,600s exhibit higher adhesive strengths than those formed at longer anodization times. The adhesive strength of the SPU coating on the nanoporous structure formed on top of TNTZ by anodization for 1,200s improves by 144% compared to that of the SPU coating on as-polished TNTZ with a mirror surface. The adhesive strength of the SPU coating on the nanotube structure formed on TNTZ by anodization for 3,600s increases by 50%. These improvements in the adhesive strength of SPU are the result of an anchor effect introduced by the nanostructures formed by anodization. Fracture occurs at the interface of the nanoporous structure and the SPU coating layer. In contrast, in the case that SPU coating has been performed on the nanotube structure, fracture occurs inside the nanotubes.

  19. Oxidation of phenol and chlorophenols on platinized titanium anodes in an acidic medium

    Science.gov (United States)

    Mokbel, Saleh Mohammed; Kolosov, E. N.; Mikhalenko, I. I.

    2016-06-01

    A comparative study of oxidation of phenol, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol on Pt/Ti and Ce,Pt/Ti electrocatalysts is performed via cyclic voltammetry. It is shown that the surface morphology and roughness of the anode do not change after modification with cerium. The formal kinetic orders of electrooxidation of all compounds are found to be less than one. It is shown that the β temperature coefficients of the rate of oxidation of chlorophenols grow by 10 to 50% when the Ce,Pt/Ti anode is used at a substrate concentration of 1 mM. A tenfold increase in concentration reduces the effect of cerium additive, except for 3-chlorophenol: the latter exhibits a 250% increase in the β value, compared to the Pt/Ti anode.

  20. Influence of Anodic Conditions on Self-ordered Growth of Highly Aligned Titanium Oxide Nanopores

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    Hernández-Vélez M

    2007-01-01

    Full Text Available AbstractSelf-aligned nanoporous TiO2templates synthesized via dc current electrochemical anodization have been carefully analyzed. The influence of environmental temperature during the anodization, ranging from 2 °C to ambient, on the structure and morphology of the nanoporous oxide formation has been investigated, as well as that of the HF electrolyte chemical composition, its concentration and their mixtures with other acids employed for the anodization. Arrays of self-assembled titania nanopores with inner pores diameter ranging between 50 and 100 nm, wall thickness around 20–60 nm and 300 nm in length, are grown in amorphous phase, vertical to the Ti substrate, parallel aligned to each other and uniformly disordering distributed over all the sample surface. Additional remarks about the photoluminiscence properties of the titania nanoporous templates and the magnetic behavior of the Ni filled nanoporous semiconductor Ti oxide template are also included.

  1. Influence of oxidative nanopatterning and anodization on the fatigue resistance of commercially pure titanium and Ti-6Al-4V.

    Science.gov (United States)

    Ketabchi, Amirhossein; Weck, Arnaud; Variola, Fabio

    2015-04-01

    With an increasingly aging population, a significant challenge in implantology is the creation of biomaterials that actively promote tissue integration and offer excellent mechanical properties. Engineered surfaces with micro- and nanoscale topographies have shown great potential to control and direct biomaterial-host tissue interactions. Two simple yet efficient chemical treatments, oxidative nanopatterning and anodization, have demonstrated the ability to confer exciting new bioactive capacities to commercially pure titanium and Ti-6Al-4V alloy. However, the resulting nanoporous and nanotubular surfaces require careful assessment in regard to potential adverse effects on the fatigue resistance, a factor which may ultimately cause premature failure of biomedical implants. In this work, we have investigated the impact of oxidative nanopatterning and anodization on the fatigue resistance of commercially pure titanium and Ti-6Al-4V. Quantitative (e.g., S-N curves) and qualitative analyses were carried out to precisely characterize the fatigue response of treated metals and compare it to that of polished controls. Scanning electron microscopy (SEM) imaging revealed the effects of cyclic loading on the fracture surface and on the structural integrity of chemically grown nanostructured oxides. Results from this study reinforce the importance of mechanical considerations in the development and optimization of micro- and nanoscale surface treatments for metallic biomedical implants.

  2. Fabrication and characterization of anodic oxide films on a Ti-10V-2Fe-3Al titanium alloy

    Institute of Scientific and Technical Information of China (English)

    Jian-hua Liu; Jun-lan Yi; Song-mei Li; Mei Yu; Yong-zhen Xu

    2009-01-01

    Anodic oxide films of the titanium alloy Ti-10V-2Fe-3Al in ammonium tartrate electrolyte without hydrofluoric acid or fluoride were fabricated.The morphology,components,and microstructure of the films were characterized by scanning electron mi-croscopy (SEM),X-ray photoelectron spectroscopy (XPS),X-ray diffraction (XRD),and Raman spectroscopy.The results showed that the films were thick,uniform,and nontransparent.Such films exhibited sedimentary morphology,with a thickness of about 3 μm,and the pore diameters of the deposits ranged from several hundred nanometers to 1.5 μm.The films were mainly titanium dioxide.Some coke-like deposits,which may contain or be changed by OH,NH,C-C,C-O,and C=O groups,were doped in the firms.The films were mainly amorphous with a small amount of anatase and rutile phase.

  3. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    measurable anode weight loss during this time period. Quantitative chemical analysis of the anode surface showed that the lead content after testing remained at its initial level. No lead dissolution or transfer from the anode to the product occurred.A key benefit of the titanium-lead anode design is that cobalt additions to copper electrolyte should be eliminated. Cobalt is added to the electrolyte to help stabilize the lead oxide surface of conventional lead anodes. The presence of the titanium intimately mixed with the lead should eliminate the need for cobalt stabilization of the lead surface. The anode should last twice as long as the conventional lead anode. Energy savings should be achieved due to minimizing and stabilizing the anode-cathode distance in the electrowinning cells. The anode is easily substitutable into existing tankhouses without a rectifier change.The copper electrowinning test data indicate that the titanium-lead anode is a good candidate for further testing as a possible replacement for a conventional lead anode. A key consideration is the cost. Titanium costs have increased. One of the ways to get the anode cost down is manufacturing the anodes with fewer cylinders. Additional prototypes having different number of cylinders were constructed for a long-term commercial testing in a circuit without cobalt. The objective of the testing is to evaluate the need for cobalt, investigate the effect of decreasing the number of cylinders on the anode performance, and to optimize further the anode design in order to meet the operating requirements, minimize the voltage, maximize the life of the anode, and to balance this against a reasonable cost for the anode. It is anticipated that after testing of the additional prototypes, a whole cell commercial test will be conducted to complete evaluation of the titanium-lead anode costs/benefits.

  4. Properties of anodic oxides grown on a hafnium–tantalum–titanium thin film library

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    Andrei Ionut Mardare

    2014-01-01

    Full Text Available A ternary thin film combinatorial materials library of the valve metal system Hf–Ta–Ti obtained by co-sputtering was studied. The microstructural and crystallographic analysis of the obtained compositions revealed a crystalline and textured surface, with the exception of compositions with Ta concentration above 48 at.% which are amorphous and show a flat surface. Electrochemical anodization of the composition spread thin films was used for analysing the growth of the mixed surface oxides. Oxide formation factors, obtained from the potentiodynamic anodization curves, as well as the dielectric constants and electrical resistances, obtained from electrochemical impedance spectroscopy, were mapped along two dimensions of the library using a scanning droplet cell microscope. The semiconducting properties of the anodic oxides were mapped using Mott–Schottky analysis. The degree of oxide mixing was analysed qualitatively using x-ray photoelectron spectroscopy depth profiling. A quantitative analysis of the surface oxides was performed and correlated to the as-deposited metal thin film compositions. In the concurrent transport of the three metal cations during oxide growth a clear speed order of Ti > Hf > Ta was proven.

  5. Effect of hot water and heat treatment on the apatite-forming ability of titania films formed on titanium metal via anodic oxidation in acetic acid solutions.

    Science.gov (United States)

    Cui, Xinyu; Kim, Hyun-Min; Kawashita, Masakazu; Wang, Longbao; Xiong, Tianying; Kokubo, Tadashi; Nakamura, Takashi

    2008-04-01

    Titanium and its alloys have been widely used for orthopedic implants because of their good biocompatibility. We have previously shown that the crystalline titania layers formed on the surface of titanium metal via anodic oxidation can induce apatite formation in simulated body fluid, whereas amorphous titania layers do not possess apatite-forming ability. In this study, hot water and heat treatments were applied to transform the titania layers from an amorphous structure into a crystalline structure after titanium metal had been anodized in acetic acid solution. The apatite-forming ability of titania layers subjected to the above treatments in simulated body fluid was investigated. The XRD and SEM results indicated hot water and/or heat treatment could greatly transform the crystal structure of titania layers from an amorphous structure into anatase, or a mixture of anatase and rutile. The abundance of Ti-OH groups formed by hot water treatment could contribute to apatite formation on the surface of titanium metals, and subsequent heat treatment would enhance the bond strength between the apatite layers and the titanium substrates. Thus, bioactive titanium metals could be prepared via anodic oxidation and subsequent hot water and heat treatment that would be suitable for applications under load-bearing conditions.

  6. Evaluation of titanium dioxide and cerium oxide as anodes for the electrooxidation of toluene A theoretical approach of the electrode process

    Energy Technology Data Exchange (ETDEWEB)

    D' Elia, Luis F.; Rincon, L.; Ortiz, R

    2004-09-30

    Cerium oxide and titanium dioxide were prepared by thermal decomposition of the precursor salts and thermal treatment of titanium plates. In aqueous medium, the metal oxides show a well-defined electrochemical reaction; a solid state redox process takes place in the cathodic range of potentials and only water discharge reaction occurs in the anodic region. At the experimental conditions, the prepared materials were not totally active for the electrooxidation of toluene. The theoretical modeling suggests that the lack of activity is due to the weak interaction between toluene and the metal oxide surface.

  7. Effect of sodium tartrate concentrations on morphology and characteristics of anodic oxide film on titanium alloy Ti–10V–2Fe–3Al

    Directory of Open Access Journals (Sweden)

    Ma Kun

    2016-08-01

    Full Text Available The effect of sodium tartrate concentrations on morphology and characteristics of anodic oxide film on titanium alloy was investigated. The alloy substrates were anodized in different concentration solutions of sodium tartrate with the addition of PTFE emulsion and their morphology and characteristics were analyzed. The anodic oxide film presented a uniform petaloid drums and micro-cracks morphology. Additionally, micro-cracks dramatically swelled with the increase of the tartrate concentrations. The thickness of the anodic oxide film increased with the concentrations until the concentration reached 15 g/L. The results of Raman analysis illustrate that all samples have similarity in the crystal structure, consisting of mainly amorphous TiO2, some anatase TiO2 and a small amount of rutile TiO2. And the ratios of anatase TiO2 and rutile TiO2 increase with the concentrations until it reaches 15 g/L. Furthermore, the intensity of the peaks increases with enhanced concentrations until the concentration reaches 15 g/L. The corrosion resistance of the anodic oxide film is increased by the sodium tartrate with higher concentrations before 15 g/L. The coefficient of friction of the anodic oxide film reduces with the concentrations until the concentration reaches 15 g/L, then the coefficient of friction of the anodic oxide film increases with the concentrations.

  8. Increased chondrocyte adhesion on nanotubular anodized titanium.

    Science.gov (United States)

    Burns, Kevin; Yao, Chang; Webster, Thomas J

    2009-03-01

    Previous studies have demonstrated increased osteoblast (bone-forming cells) functions (including adhesion, synthesis of intracellular collagen, alkaline phosphatase activity, and deposition of calcium-containing minerals) on titanium anodized to possess nanometer features compared with their unanodized counterparts. Such titanium materials were anodized to possess novel nanotubes also capable of drug delivery. Since titanium has not only experienced wide spread commercial use in orthopedic but also in cartilage applications, the objective of the present in vitro study was for the first time to investigate chondrocyte (cartilage synthesizing cells) functions on titanium anodized to possess nanotubes. For this purpose, titanium was anodized in dilute hydrofluoric acid at 20 V for 20 min. Results showed increased chondrocyte adhesion on anodized titanium with nanotube structures compared with unanodized titanium. Importantly, the present study also provided evidence why. Since material characterization studies revealed significantly greater nanometer roughness and similar chemistry as well as crystallinity between nanotubular anodized and unanodized titanium, the results of the present study highlight the importance of the nanometer roughness provided by anodized nanotubes on titanium for enhancing chondrocyte adhesion. In this manner, the results of the present in vitro study indicated that anodization might be a promising quick and inexpensive method to modify the surface of titanium-based implants to induce better chondrocyte adhesion for cartilage applications.

  9. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  10. Study for preparation of nanoporous titania on titanium by anodic oxidation; Estudo da preparacao de titania nanoporosa sobre titanio por oxidacao anodica

    Energy Technology Data Exchange (ETDEWEB)

    Passos, Alessandra Pires

    2014-07-01

    Currently titanium is the most common material used in dental, orthopedic implants and cardiovascular applications. In the mid 1960s, prof. Braenemark and coworkers developed the concept of osseointegration, meaning the direct structural and functional connection between living bone and the surface of artificial implant. Thus, studies on the modification of the implant surface are widely distributed among them are the acid attack, blasting with particles of titanium oxide or aluminum oxide, coating with bioactive materials such as hydroxyapatite, and the anodic oxidation. The focus of this work was to investigate the treatment of titanium surface by anodic oxidation. The aim was to develop a nanoporous titanium oxide overlay with controlled properties over titanium substrates. Recent results have shown that such surface treatment improves the biological interaction at the interface bone-implant besides protecting the titanium further oxidation and allow a faster osseointegration. The anodizing process was done in the potentiostatic mode, using an electrolyte composed of 1.0 mol/L H{sub 3}PO{sub 4} and HF 0.5% m/I. The investigated process parameters were the electrical potential (Va) and the process time (T). The electric potential was varied from 10 V to 30 V and the process time was defined as 1.0 h, 1.5 h or 2.0 h. The treated Ti samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy X-ray (EDS), and X-ray diffraction (XRD). The results showed the formation of nanoporous titanium oxide by anodizing with electric potential (Va) in the range of 20 V to 30 V and process time in the range of 1 to 2 hours. The average pore diameter was in the range 94-128 nm. Samples anodized in electric potential lower than 20 V did not show the formation of the nanoporous surface. In the case of Va above 30 V, it was observed the formation of agglomerates of TiO{sub 2}. The results obtained in this study

  11. Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.Y., E-mail: yshy2004@hotmail.com [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Feng, C.Q. [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Wu, S.J.; Liu, H.L.; Ke, B.Q. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Zhang, K.L. [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Chen, D.H. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South Central University for Nationalities, Wuhan 430074, Hubei (China)

    2015-09-05

    Highlights: • Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} has been successfully synthesized via a molten salt route. • Calcination temperature is an important effect on the component and microstructure of the product. • Pure phase Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} could be obtained at 700 °C for 2 h. - Abstract: The sodium lithium titanium oxide with composition Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 14} has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700 °C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700 °C revealed highly reversible insertion and extraction of Li{sup +} and displayed a single potential plateau at around 1.3 V. The product obtained at 700 °C for 2 h exhibits good cycling properties and retains the specific capacity of 62 mAh g{sup −1} after 500 cycles.

  12. Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environments

    Directory of Open Access Journals (Sweden)

    Mr. Sunil D. Kahar

    2014-07-01

    Full Text Available Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.

  13. Cell response of anodized nanotubes on titanium and titanium alloys.

    Science.gov (United States)

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells.

  14. The effect of surface microgrooves and anodic oxidation on the surface characteristics of titanium and the osteogenic activity of human periodontal ligament cells.

    Science.gov (United States)

    Lee, Myung Hyun; Kang, Jong Ho; Lee, Suk Won

    2013-01-01

    The purpose of this study was to investigate the effect of titanium (Ti) surface microgrooves and anodic oxidation on the surface characteristics of titanium and the osteogenic activity of human periodontal ligament cells (PLCs) cultured on theses surfaces. Mechanically ground Ti was used as the control substratum (NE0). Truncated V-shaped microgrooves, 60μm-wide and 10μm-deep in cross-sections, were created on the Ti substrata by photolithography (NE60/10). Anodically oxidized Ti (NE0AO) and anodically oxidized microgrooved Ti (NE60/10AO) were also prepared. Scanning electron microscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were performed for surface characterization. Cell proliferation assay, osteoblast differentiation assay, and quantitative real-time PCR analysis were performed to compare the osteogenic activity of PLCs on NE0, NE60/10, NEAO, and NE60/10AO. A decrease in the microgroove-width of NE60/10AO compared to NE60/10 due to Ti oxide layer generation by anodic oxidation was detected with XRD and XPS. Cell proliferation, osteoblast differentiation, and osteo-related gene expression were enhanced on the NE60/10AO substrata compared with NE0, NE60/10, and NE0AO. The combination of Ti surface microgrooves and subsequent anodic oxidation treatment synergistically upregulated osteo-related gene expression, despite showing limited ability to increase cell proliferation and osteoblast differentiation levels in PLCs. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. High-Temperature Stable Anatase Titanium Oxide Nanofibers for Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Lee, Sangkyu; Eom, Wonsik; Park, Hun; Han, Tae Hee

    2017-08-02

    Control of the crystal structure of electrochemically active materials is an important approach to fabricating high-performance electrodes for lithium-ion batteries (LIBs). Here, we report a methodology for controlling the crystal structure of TiO2 nanofibers by adding aluminum isopropoxide to a common sol-gel precursor solution utilized to create TiO2 nanofibers. The introduction of aluminum cations impedes the phase transformation of electrospun TiO2 nanofibers from the anatase to the rutile phase, which inevitably occurs in the typical annealing process utilized for the formation of TiO2 crystals. As a result, high-temperature stable anatase TiO2 nanofibers were created in which the crystal structure was well-maintained even at high annealing temperatures of up to 700 °C. Finally, the resulting anatase TiO2 nanofibers were utilized to prepare LIB anodes, and their electrochemical performance was compared to pristine TiO2 nanofibers that contain both anatase and rutile phases. Compared to the electrode prepared with pristine TiO2 nanofibers, the electrode prepared with anatase TiO2 nanofibers exhibited excellent electrochemical performances such as an initial Coulombic efficiency of 83.9%, a capacity retention of 89.5% after 100 cycles, and a rate capability of 48.5% at a current density of 10 C (1 C = 200 mA g(-1)).

  16. Bacterial adherence to anodized titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Peremarch, C Perez-Jorge; Tanoira, R Perez; Arenas, M A; Matykina, E; Conde, A; De Damborenea, J J; Gomez Barrena, E; Esteban, J, E-mail: cperemarch@fjd.es

    2010-11-01

    The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

  17. Electrochemical anodizing treatment to enhance localized corrosion resistance of pure titanium.

    Science.gov (United States)

    Prando, Davide; Brenna, Andrea; Bolzoni, Fabio M; Diamanti, Maria V; Pedeferri, Mariapia; Ormellese, Marco

    2017-01-26

    Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

  18. 钛表面阳极氧化膜的腐蚀行为研究%Study of corrosion behavior of titanium with anodized oxidation film

    Institute of Scientific and Technical Information of China (English)

    于卫强; 邱憬; 张富强

    2011-01-01

    目的 探讨钛阳极氧化前后腐蚀性能的变化.方法 钛表面阳极氧化法制备TiO2纳米管,扫描电镜观察氧化膜的微结构,X线衍射分析氧化膜煅烧前后晶型的变化,极化曲线分析钛阳极氧化前后对腐蚀性能的影响.结果 阳极氧化后,钛表面呈现管径80 nm,管长400 nm的纳米管状结构;X线衍射分析表明阳极氧化膜煅烧后变为锐钛矿晶型;电化学实验表明:光滑钛的破钝电位低于煅烧前后的阳极氧化膜(P<0.05),自腐蚀电位的绝对值、自腐蚀电流和钝化区电流高于煅烧前后的阳极氧化膜(P<0.05),煅烧后钛表面阳极氧化膜的腐蚀性能较煅烧前有所改善,但未见统计学差异.结论 钛经过阳极氧化处理后,表面形成的TiO2纳米管结构可以提高钛的抗腐蚀性能.%Objective To investigate the variation of the corrosion resistance of anodized oxidation film on titanium by electrochemical methods. Methods TiO2 nanotube layer was formed on Ti surface by anodization. The morphology was observed with scanning electron microscope(SEM) and the crystal phase was analyzed using X-ray diffraction(XRD) before and after annealing. Polarization curves were examined by electrochemical methods. Results Titanium oxide nanotubes with 80 nm diameter and 400 nm length was seen on Ti after anodization. The annealing nanotubes was anatase crystalline phase by X-ray diffraction analysis. The self-corrosion potential and break-down potential of smooth Ti were significantly lower than TiO2 nanotubes by anodization (P<0.05). The self-corrosion current and passived current were significantly higher than Ti02 nanotubes by anodization (P<0.05). Annealing improved the corrosion resistance of anodized oxidation film on titanium. Conclusion The resuIts of electrochemical examinations indicate that the TiO2 nanotubes by anodization increases the corrosion resistance of titanium.

  19. Sub-stoichiometric titanium oxide (Ti4O7) as a suitable ceramic anode for electrooxidation of organic pollutants: A case study of kinetics, mineralization and toxicity assessment of amoxicillin.

    Science.gov (United States)

    Ganiyu, Soliu O; Oturan, Nihal; Raffy, Stéphane; Cretin, Marc; Esmilaire, Roseline; van Hullebusch, Eric; Esposito, Giovanni; Oturan, Mehmet A

    2016-12-01

    Electrochemical degradation of aqueous solutions containing antibiotic amoxicillin (AMX) has been extensively studied in an undivided electrolytic cell using a sub-stoichiometric titanium oxide (Ti4O7) anode, elaborated by plasma deposition. Oxidative degradation of AMX by hydroxyl radicals was assessed as a function of applied current and was found to follow pseudo-first order kinetics. The use of carbon-felt cathode enhanced oxidation capacity of the process due to the generation of H2O2. Comparative studies at low current intensity using dimensional stable anode (DSA) and Pt anodes led to the lower mineralization efficiencies compared to Ti4O7 anode: 36 and 41% TOC removal for DSA and Pt respectively compared to 69% for Ti4O7 anode. Besides, the use of boron doped diamond (BDD) anode under similar operating conditions allowed reaching higher mineralization (94%) efficiency. Although Ti4O7 anode provides a lesser mineralization rate compared to BDD, it exhibits better performance compared to the classical anodes Pt and DSA and can constitutes an alternative to BDD anode for a cost effective electro-oxidation process. Moreover several aromatic and aliphatic oxidation reaction intermediates and inorganic end-products were identified and a plausible mineralization pathway of AMX involving these intermediates was proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 电解铜箔用涂层钛阳极表面结垢的去除%Descaling of oxide-coated titanium anode for manufacturing of electrolytic copper foils

    Institute of Scientific and Technical Information of China (English)

    徐海清; 胡耀红; 陈力格; 秦足足; 廖磊华; 张招贤

    2015-01-01

    采用X射线衍射(XRD)、X射线荧光光谱分析(XRF)测试了失效电解铜箔用钛阳极表面结垢成分,考察了BH−阳极除垢剂对电解铜箔用钛阳极表面结垢的去除效果,通过循环伏安曲线、极化曲线、强化寿命测试分析了 BH−阳极除垢剂对钛阳极电催化活性的影响,给出了电解铜箔用钛阳极在应用过程中的维护措施。结果表明,BH−阳极除垢剂可以有效去除结垢而不会破坏钛阳极表面的贵金属涂层,有利于延长钛阳极的寿命。%The composition of scale formed on surface of failure titanium anode used for manufacturing of electrolytic copper foils was examined by X-ray diffraction (XRD) and X-ray fluorescence analysis (XRF). The effectiveness of BH anode descaling agent on the oxide-titanium anode used for electrolytic copper foils was studied and its influence on electrocatalytic activity of the anode was analyzed through cyclic voltammetry, polarization curve measurement, and accelerated service life test. The maintenance methods for oxide-coated titanium anode during the manufacturing of electrolytic copper foils were presented. The results indicated that the BH anode descaling agent removes the scales effectively, and has no damage to the precious metal oxide coating, extending the service life of the oxide-coated titanium anode.

  1. Preparation and application of a titanium dioxide/graphene oxide anode material for lithium-ion batteries

    Science.gov (United States)

    Siwińska-Stefańska, Katarzyna; Kurc, Beata

    2015-12-01

    This paper describes the synthesis and physicochemical properties of a new type of titania/graphene oxide (TA/GO) composite. Titania powder was synthesized via the sol-gel method, and its surface was functionalized with N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS) to increase its adhesion to graphene oxide. Transmission electron microscopy (TEM), non-invasive back scattering (NIBS), porous structure parameters (low-temperature nitrogen sorption), degree of modification of titania and TA/GO determined by Fourier-transform infrared spectroscopy (FT-IR), impedance analysis, charging/discharging and cyclic voltammetry were carried out. At a current density of 50 mA g-1, the good cyclability exhibited by the TA/GO anode can be readily retained at 370 mAh g-1 after 50 cycles, which is outstanding among the TiO2 composites reported in the literature.

  2. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  3. Biocompatibility and in vitro antineoplastic drug-loaded trial of titania nanotubes prepared by anodic oxidation of a pure titanium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    TiO2 nanotube (NT) arrays have been prepared by anodic oxidation of a Ti sheet,and carbon-deposited TiO2 NT arrays have been prepared by annealing TiO2 NT arrays in carbon atmosphere. The biocompatibility of the as-prepared NT arrays was investigated by observing the growth of osteosarcoma (MG-63) cells on the NT arrays. The application of the TiO2 NT arrays as a drug delivery vehicle was investigated. Both the TiO2 NTs and the carbon-modified TiO2 NTs have good biocompatibility supporting the normal growth and adhesion of MG-63 cells with no need of extracellular matrix protein coating. The one end-opened TiO2 NTs can be easily filled with drugs,working as an efficient drug delivery vehicle.

  4. Growth of anatase titanium dioxide nanotubes via anodization

    Directory of Open Access Journals (Sweden)

    Ed Adrian Dilla

    2012-06-01

    Full Text Available In this work, titanium dioxide nanotubes were grown via anodization of sputtered titanium thin films using different anodization parameters in order to formulate a method of producing long anatase titanium dioxide nanotubes intended for solar cell applications. The morphological features of the nanotubes grown via anodization were explored using a Philips XL30 Field Emission Scanning Electron Microscope. Furthermore, the grown nanotubes were also subjected to X-ray diffraction and Raman spectroscopy in order to investigate the effect of the predominant crystal orientation of the parent titanium thin film on the crystal phase of the nanotubes. After optimizing the anodization parameters, nanotubes with anatase TiO2 crystal phase and tube length more than 2 microns was produced from parent titanium thin films with predominant Ti(010 crystal orientation and using ammonium fluoride in ethylene glycol as an electrolyte with a working voltage equal to 60V during 1-hour anodization runs.

  5. Characterization and corrosion resistance of anodic electrodeposited titanium oxide/phosphate films on Ti-20Nb-10Zr-5Ta bioalloy

    Energy Technology Data Exchange (ETDEWEB)

    Popa, Monica; Vasilescu, Cora; Drob, Silviu I.; Osiceanu, Petre; Anastasescu, Mihai; Calderon-Moreno, Jose M., E-mail: josecalderonmoreno@yahoo.com [Institute of Physical Chemistry ' Ilie Murgulescu' of the Romanian Academy, Bucharest (Romania)

    2013-07-15

    In this work, the anodic galvanostatic electrodeposition of an oxidation film containing phosphates on Ti-20Nb-10Zr-5Ta alloy from orthophosphoric acid solution is presented. Its composition was determined by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman micro-spectroscopy, and its topography by atomic force microscopy (AFM). The corrosion resistance of the coated alloy in simulated human fluid (by linear polarization method and monitoring of open circuit potentials, corresponding open circuit potential gradients) as well as the characterization of the coating (by Raman spectroscopy and depth profile X-ray photoelectron spectroscopy (XPS)) deposited in a period of 300 h soaking in simulated human body fluid were studied. The electrodeposited film was composed of amorphous titanium dioxide and contained phosphate groups. The corrosion resistance of the coated Ti-20Nb-10Zr-5Ta alloy in neutral and alkaline Ringer's solutions was higher than that of the bare alloy due to the protective properties of the electrodeposited film. The corrosion parameters improved over time as result of the thickening of the surface film by the deposition from the physiological solution. The deposited coating presented a variable composition in depth: at the deeper layer nucleated nanocrystalline hydroxyapatite and at the outer layer amorphous calcium phosphate. (author)

  6. HA coating on titanium with nanotubular anodized TiO2 intermediate layer via electrochemical deposition

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-qin; TAO Jie; WANG Ling; HE Ping-ting; WANG Tao

    2008-01-01

    Hydroxyapatite (HA) coating has been prepared on titanium substrate through an electrochemical deposition approach.In order to improve the bonding strength between HA coating and Ti substrate,a well oriented and uniform titanium oxide nanotube array on the surface of titanium substrate was applied by means of anodic oxidation pre-treatment.Then the calcium hydrogen phosphate (CaHPO4-2H2O,DCPD) coating,as the precursor of hydroxyapatite coating,was electrodeposited on the anodized Ti.At the initial stage of electro-deposition,the DCPD crystals,in nanometer precipitates,are anchored in and between the tubes.With increasing the deposition time,the nanometer DCPD crystals are connected together to form a continuous coating on titanium oxide nanotube array.Finally,the DCPD coating is converted into hydroxyapatite one simply by being immersed in alkaline solution.

  7. Niobium-doped titanium oxide anode and ionic liquid electrolyte for a safe sodium-ion battery

    Science.gov (United States)

    Usui, Hiroyuki; Domi, Yasuhiro; Shimizu, Masahiro; Imoto, Akinobu; Yamaguchi, Kazuki; Sakaguchi, Hiroki

    2016-10-01

    The anode properties of Nb-doped rutile TiO2 electrodes were investigated in an ionic liquid electrolyte comprised of N-methyl-N-propylpyrrolidinium cation and bis(fluorosulfonyl)amide anion for use in a safe Na-ion battery. Although the electrolyte's conductivity was lower than that of a conventional organic electrolyte at 30 °C, it showed high conductivity comparable to that of the organic electrolyte at 60 °C. The Nb-doped TiO2 electrode showed excellent cyclability in the ionic liquid electrolyte at 60 °C: a high capacity retention of 97% was observed even at the 350th cycle, which is comparable to value in the organic electrolyte (91%). In a non-flammability test in a closed system, no ignition was observed with the ionic liquid electrolyte even at 300 °C. These results indicate that combination of a Nb-doped TiO2 anode and ionic liquid electrolyte gives not only an excellent cyclability but also high safety for a Na-ion battery operating at a temperature below the sodium's melting point of 98 °C.

  8. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Parcharoen, Yardnapar [Department of Biological Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Kajitvichyanukul, Puangrat [Center of Excellence on Environmental Research and Innovation, Faculty of Engineering, Naresuan University, Phitsanulok (Thailand); Sirivisoot, Sirinrath [Department of Biological Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Termsuksawad, Preecha, E-mail: preecha.ter@kmutt.ac.th [Division of Materials Technology, School of Energy, Environment and Materials, King Mongkut' s University of Technology Thonburi, 126 Pracha Uthit Rd., Bang Mod, ThungKhru, Bangkok 10140 (Thailand)

    2014-08-30

    Highlights: • We found that different anodization time of titanium significantly effects on nanotube length which further impacts adhesion strength of hydroxyapatite coating layers. • Adhesion strength of Hydroxyapatite (HA) coated on titanium dioxide nanotubes is better than that of HA coated on titanium plate. • Hydroxyapatite coated on titanium dioxide nanotubes showed higher cell density and better spreading of MC3T3-E1 cells (bone-forming cells) than that coated on titanium plate surface. - Abstract: Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO{sub 2}) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO{sub 2} nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH{sub 4}F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO{sub 2} nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO{sub 2} nanotubes were found when high viscous electrolyte, NH{sub 4}F in glycerol, was used. Negative voltage (−4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO{sub 2} nanotubes was significantly increased by times. The TiO{sub 2} nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO{sub 2} nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that

  9. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features

    Directory of Open Access Journals (Sweden)

    Balasubramanian K

    2011-08-01

    Full Text Available Amancherla Rajyalakshmi1, Batur Ercan2,3, K Balasubramanian1, Thomas J Webster2,31Non-Ferrous Materials Technology Development Centre, Hyderabad, India; 2School of Engineering, 3Department of Orthopedics, Brown University, Providence, RI, USAAbstract: One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti leads to the formation of TiO2 nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF for 1 minute, nanotextured (nonnanotube surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40–50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60–70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.Keywords: anodization, titanium

  10. Titanium Oxide Nanotubes Prepared by Anodic Oxidation and Their Application in Solar Cells%阳极氧化法制备二氧化钛纳米管及其在太阳能电池中的应用

    Institute of Scientific and Technical Information of China (English)

    李欢欢; 陈润锋; 马琮; 张胜兰; 安众福; 黄维

    2011-01-01

    We review the history, fabrication procedures, and mechanisms of TiO2 nanotubes prepared by the anodic oxidation of titanium.The influence of various preparation factors, such as electrolytes, pH value, voltage, bath temperature, and post treatment, on the structure and morphology of the TiO2 nanotubes are discussed.This review also summarizes the application of TiO2 nanotubes to dye-sensitized solar cells, quantum dot solar cells, and bulk heterojunction solar cells.A perspective on the future development of TiO2nanotubes and their applications is tentatively discussed.%介绍了阳极氧化法制备二氧化钛纳米管的技术发展历程,论述了其制备过程及生长机理,探讨了电解液、pH值、氧化电压、氧化时间、氧化温度和后处理方法等因素对TiO2纳米管结构和形态的影响,综述了近几年来利用TiO2纳米管组装染料敏化、量子点和本体异质结等太阳能电池所取得的进展,展望了其未来发展趋势和应用前景.

  11. Tuning anatase and rutile phase ratios and nanoscale surface features by anodization processing onto titanium substrate surfaces.

    Science.gov (United States)

    Roach, M D; Williamson, R S; Blakely, I P; Didier, L M

    2016-01-01

    Both the anatase (A) and rutile (R) phases of titanium oxide have shown enhanced antimicrobial and bioactivity levels but the specific A/R phase ratio needed for the best results is still unknown. In this study titanium samples were anodized to produce specific ratios of anatase and rutile phases within the oxide layers. Specific ratios produced included maximum A minimum R, minimum A maximum R, 50% A 50% R, minimum A minimum R, and a non-anodized titanium control group. Samples were characterized for phase distributions within the oxide layers, surface porosity, corrosion resistance, and bioactivity. Results indicated the targeted phase ratios were reproducibly achieved during the anodization process. Samples containing the highest levels of anatase showed the largest individual pore sizes, but a lower overall percent porosity value compared to samples containing higher rutile levels. EBSD examination of the anodized layer cross-sections provided valuable new spatial information on the distribution of anatase and rutile phases within the anodized layers. Highly porous oxide layers showed significantly higher corrosion rates compared to non-anodized titanium, but no significant differences were shown in the icorr values between samples containing primarily anatase phase, samples containing primarily rutile phase, and samples containing an approximate 50:50 mixture of the two phases. Minimum A minimum R samples showed substantially less porosity compared to the other anodization groups, a significantly lower oxide thickness, and comparable corrosion rates to non-anodized titanium. All samples within the study showed apatite production in simulated body fluid within the seven day test period indicating enhanced bioactivity.

  12. Titanium oxide nanotube arrays prepared by anodic oxidation method and photocatalytic degradation of chloramine phosphorus%阳极氧化法制备氧化钛纳米管阵列及光催化降解氯胺磷

    Institute of Scientific and Technical Information of China (English)

    龚青; 尹荔松; 郭智博; 阳素玉; 安科云

    2011-01-01

    Using anodic oxidation in HF+ACOH+PEG solution at the constant voltage to deal with the titanium foil, the high-density TiO2 nanotube arrays with regular and orderly structure were prepared. The morphology of the nanotubes was characterized by SEM, and the crystal of the nanotubes was analyzed by XRD. The effect of oxidation time on the morphology and size of nanotube arrays were studied, and the current-time curve was obtained. The photocatalytic activities were evaluated by degradation of chloramine phosphorus. The ratio of degradation was measured and calculated by Molybdenum- Antimony Anti-Spectrophotometric method. The influences of annealing temperature and anodic oxidation time of solution were analyzed. The sol-gel method was used to prepare TiC>2 thin film, which is used to do photocatalytic comparative experiments.%采用阳极氧化法在氢氟酸+冰醋酸+聚乙二醇水溶液恒压处理钛箔,制备结构规整有序的高密度TiO2纳米管阵列.利用电子扫描电镜(SEM)和X线衍射仪(XRD)对纳米管形貌和结构进行表征,考察氧化时间对纳米管阵列形貌和尺寸的影响,绘制并分析电流-时间曲线.选用有机磷药氯胺磷为光催化降解对象,利用钼锑抗分光光度法测量并计算降解率,研究不同热处理温度和阳极氧化时间对光催化降解效果的影响,并采用溶胶-凝胶法制备TiO2纳米薄膜进行光催化对比实验.

  13. 阳极氧化钛表面淫羊藿苷/PHBV药物缓释涂层的制备与表征%Preparation and characterization of icariin/PHBV drug delivery coatings on anodic oxidized titanium

    Institute of Scientific and Technical Information of China (English)

    戴瑶; 刘海蓉; 夏磊磊; 周征

    2011-01-01

    A composite material was fabricated by applying a biodegradable drug delivery coating,consisting of poly (3-hydroxyburyrate-co-3-hydroxyvalerate) (PHBV) and icariin,to an anodic oxidized titanium plate.The coating was prepared by evaporating chloroform solution containing PHBV and icariin on the titanium plate under vacuum condition.Icariin/PHBV coated titanium plates significantly enhance the proliferation of MG-63 cells compared with the PHBV coated and anodic oxidized ones.Increased icariin contained in the coating displays an elevated influence on cell proliferation.The results show that icariin gradually releases from the coating to cells mainly through the phospholipid-based cellular membrane instead of the culture medium.The overall results suggest that the novel icariin/PHBV coating can be used to enhance the bioactivity of titanium based orthopedic implants.%以聚3-羟基丁酸酯-co-3-羟基戊酸酯(PHBV)和中药淫羊藿苷的三氯甲烷溶液为原料,通过真空干燥使溶剂挥发,在阳极氧化钛表面制备可降解的药物缓释涂层.体外细胞实验表明,相比于阳极氧化钛和PHBV涂层,含淫羊藿苷PHBV涂层能够显著地促进成骨细胞MG-63在其表面增殖,并且随着涂层中淫羊藿苷含量的增加,促进细胞增殖的作用越明显.淫羊藿苷主要通过细胞膜吸收而不是通过溶解在培养液中的方式发挥作用.结果表明,此药物缓释涂层能够有效增强钛植入材料的生物活性.

  14. Electrolyte effects on the surface chemistry and cellular response of anodized titanium

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsu, Naofumi, E-mail: nohtsu@mail.kitami-it.ac.jp [Instrumental Analysis Center, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Kozuka, Taro; Hirano, Mitsuhiro [Instrumental Analysis Center, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Arai, Hirofumi [Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, Kitami, Hokkaido 090-8507 (Japan)

    2015-09-15

    Highlights: • Ti samples were anodized using various electrolytes. • Anodization decreased carbon adsorption, improving hydrophilicity. • Improved hydrophilicity led to improved cellular attachment. • Only one electrolyte showed any heteroatom incorporation into the TiO{sub 2} layer. • Choice of electrolyte played no role on the effects of anodization. - Abstract: Anodic oxidation of titanium (Ti) material is used to enhance biocompatibility, yet the effects of various electrolytes on surface characteristics and cellular behavior have not been completely elucidated. To investigate this topic, oxide layers were produced on Ti substrates by anodizing them in aqueous electrolytes of (NH{sub 4}){sub 2}O·5B{sub 2}O{sub 3}, (NH{sub 4}){sub 2}SO{sub 4}, or (NH{sub 4}){sub 3}PO{sub 4}, after which their surface characteristics and cellular responses were examined. Overall, no surface differences between the electrolytes were visually observed. X-ray photoelectron spectroscopy (XPS) revealed that the anodized surfaces are composed of titanium dioxide (TiO{sub 2}), while incorporation from electrolyte was only observed for (NH{sub 4}){sub 3}PO{sub 4}. Surface adsorption of carbon contaminants during sterilization was suppressed by anodization, leading to lower water contact angles. The attachment of MC3T3-E1 osteoblast-like cells was also improved by anodization, as evidenced by visibly enlarged pseudopods. This improved attachment performance is likely due to TiO{sub 2} formation. Overall, electrolyte selection showed no effect on either surface chemistry or cellular response of Ti materials.

  15. Differences in the electrochemical behavior of ruthenium and iridium oxide in electrocatalytic coatings of activated titanium anodes prepared by the sol–gel procedure

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIĆ

    2010-10-01

    Full Text Available The electrochemical characteristics of Ti0.6Ir0.4O2/Ti and Ti0.6Ru0.4O2/Ti anodes prepared by the sol–gel procedure from the corresponding oxide sols, obtained by force hydrolysis of the corresponding metal chlorides, were compared. The voltammetric properties in H2SO4 solution indicate that Ti0.6Ir0.4O2/Ti has more pronounced pseudocapacitive characteristics, caused by proton-assisted, solid state surface redox transitions of the oxide. At potentials negative to 0.0 VSCE, this electrode is of poor conductivity and activity, while the voltammetric behavior of the Ti0.6Ru0.4O2/Ti electrode is governed by proton injection/ejection into the oxide structure. The Ti0.6Ir0.4O2/Ti electrode had a higher electrocatalytical activity for oxygen evolution, while the investigated anodes were of similar activity for chlorine evolution. The potential dependence of the impedance characteristics showed that the Ti0.6Ru0.4O2/Ti electrode behaved like a capacitor over a wider potential range than the Ti0.6Ir0.4O2/Ti electrode, with fully-developed pseudocapacitive properties at potentials positive to 0.60 VSCE. However, the impedance characteristics of the Ti0.6Ir0.4O2/Ti electrode changed with increasing potential from resistor-like to capacitor-like behavior.

  16. Effect of anodization on corrosion behaviour and biocompatibility of Cp-titanium in simulated body fluid

    Indian Academy of Sciences (India)

    Archana Singh; B P Singh; Mohan R Wani; Dinesh Kumar; J K Singh; Vakil Singh

    2013-10-01

    The objective of this investigation is to study the effectiveness of anodized surface of commercial purity titanium (Cp-Ti) on its corrosion behaviour in simulated body fluid (SBF) and proliferation of osteoblast cells on it, to assess its potentiality as a process of surface modification in enhancing corrosion resistance and osseointegration of dental implants. Highly ordered nano-porous oxide layer, with nano-sized pores, is developed on the surface of Cp-Ti through electrochemical anodization in the electrolyte of aqueous solution of 0.5% HF at 15 V for 30 min at 24 °C. The nano-porous feature of the anodized surface is characterized by field-emission scanning electron microscope (FESEM). Pores of some anodized samples are sealed by exposing the anodized surface in boiling water. Corrosion behaviour of the anodized specimen is studied in Ringer’s solution at 30 ± 2 °C, using electrochemical impedance and cyclic polarization technique. Biocompatibility of the anodized surface is accessed using MG63 osteoblast cells. Both corrosion as well as pitting resistance of Cp-Ti in simulated body fluid are found to be highest in the anodized and sealed condition and followed in decreasing order by those of anodized and unanodized ones. Significantly higher MG63 osteoblast cell proliferations are found on the anodized surface than that on the unanodized one. Anodized Cp-Ti develops nano-size surface pores, like that of natural bone. It enhances corrosion and pitting resistance and also the process of osteoblast cell proliferation on Cp-Ti.

  17. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    Science.gov (United States)

    Parcharoen, Yardnapar; Kajitvichyanukul, Puangrat; Sirivisoot, Sirinrath; Termsuksawad, Preecha

    2014-08-01

    Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO2) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO2 nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH4F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO2 nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO2 nanotubes were found when high viscous electrolyte, NH4F in glycerol, was used. Negative voltage (-4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO2 nanotubes was significantly increased by times. The TiO2 nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO2 nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that growing on titanium plate surface.

  18. Plasma electrolytic oxidation of Titanium Aluminides

    Science.gov (United States)

    Morgenstern, R.; Sieber, M.; Grund, T.; Lampke, T.; Wielage, B.

    2016-03-01

    Due to their outstanding specific mechanical and high-temperature properties, titanium aluminides exhibit a high potential for lightweight components exposed to high temperatures. However, their application is limited through their low wear resistance and the increasing high-temperature oxidation starting from about 750 °C. By the use of oxide ceramic coatings, these constraints can be set aside and the possible applications of titanium aluminides can be extended. The plasma electrolytic oxidation (PEO) represents a process for the generation of oxide ceramic conversion coatings with high thickness. The current work aims at the clarification of different electrolyte components’ influences on the oxide layer evolution on alloy TNM-B1 (Ti43.5Al4Nb1Mo0.1B) and the creation of compact and wear resistant coatings. Model experiments were applied using a ramp-wise increase of the anodic potential in order to show the influence of electrolyte components on the discharge initiation and the early stage of the oxide layer growth. The production of PEO layers with technically relevant thicknesses close to 100 μm was conducted in alkaline electrolytes with varying amounts of Na2SiO3·5H2O and K4P2O7 under symmetrically pulsed current conditions. Coating properties were evaluated with regard to morphology, chemical composition, hardness and wear resistance. The addition of phosphates and silicates leads to an increasing substrate passivation and the growth of compact oxide layers with higher thicknesses. Optimal electrolyte compositions for maximum coating hardness and thickness were identified by statistical analysis. Under these conditions, a homogeneous inner layer with low porosity can be achieved. The frictional wear behavior of the compact coating layer is superior to a hard anodized layer on aluminum.

  19. Electrochemical oxidation of trace organic contaminants in reverse osmosis concentrate using RuO2/IrO2-coated titanium anodes.

    Science.gov (United States)

    Radjenovic, Jelena; Bagastyo, Arseto; Rozendal, René A; Mu, Yang; Keller, Jürg; Rabaey, Korneel

    2011-02-01

    During membrane treatment of secondary effluent from wastewater treatment plants, a reverse osmosis concentrate (ROC) containing trace organic contaminants is generated. As the latter are of concern, effective and economic treatment methods are required. Here, we investigated electrochemical oxidation of ROC using Ti/Ru(0.7)Ir(0.3)O(2) electrodes, focussing on the removal of dissolved organic carbon (DOC), specific ultra-violet absorbance at 254 nm (SUVA(254)), and 28 pharmaceuticals and pesticides frequently encountered in secondary treated effluents. The experiments were conducted in a continuously fed reactor at current densities (J) ranging from 1 to 250 A m(-2) anode, and a batch reactor at J = 250 A m(-2). Higher mineralization efficiency was observed during batch oxidation (e.g. 25.1 ± 2.7% DOC removal vs 0% removal in the continuous reactor after applying specific electrical charge, Q = 437.0 A h m(-3) ROC), indicating that DOC removal is depending on indirect oxidation by electrogenerated oxidants that accumulate in the bulk liquid. An initial increase and subsequent slow decrease in SUVA(254) during batch mode suggests the introduction of auxochrome substituents (e.g. -Cl, NH(2)Cl, -Br, and -OH) into the aromatic compounds. Contrarily, in the continuous reactor ring-cleaving oxidation products were generated, and SUVA(254) removal correlated with applied charge. Furthermore, 20 of the target pharmaceuticals and pesticides completely disappeared in both the continuous and batch experiments when applying J ≥ 150 A m(-2) (i.e. Q ≥ 461.5 A h m(-3)) and 437.0 A h m(-3) (J = 250 A m(-2)), respectively. Compounds that were more persistent during continuous oxidation were characterized by the presence of electrophilic groups on the aromatic ring (e.g. triclopyr) or by the absence of stronger nucleophilic substituents (e.g. ibuprofen). These pollutants were oxidized when applying higher specific electrical charge in batch mode (i.e. 1.45 kA h m(-3) ROC

  20. Photocatalytic activity of porous TiO2 films prepared by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; WANG Tao; WANG Ling

    2007-01-01

    Anatase titanium dioxide is an active photocatalyst, however, it is difficult to be immobilized on the substrate.The crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation. The film was then used for photocatalysis via the methyl orange degradation method. The effects of anodization voltage, pH value, TiO2 film area and degradation time on the photocatalyst were investigated respectively by UV-visible spectrum. It was indicated that the TiO2 film prepared by anodic oxidation at 140 V had the best photocatalysis capability and the degradation of methyl orange was accelerated with acid addition.

  1. Enhanced osteoblast adhesion to drug-coated anodized nanotubular titanium surfaces.

    Science.gov (United States)

    Eaninwene, George; Yao, Chang; Webster, Thomas J

    2008-01-01

    Current orthopedic implants have functional lifetimes of only 10-15 years due to a variety of reasons including infection, extensive inflammation, and overall poor osseointegration (or a lack of prolonged bonding of the implant to juxtaposed bone). To improve properties of titanium for orthopedic applications, this study anodized and subsequently coated titanium with drugs known to reduce infection (penicillin/streptomycin) and inflammation (dexamethasone) using simple physical adsorption and the deposition of such drugs from simulated body fluid (SBF). Results showed improved drug elution from anodized nanotubular titanium when drugs were coated in the presence of SBF for up to 3 days. For the first time, results also showed that the simple physical adsorption of both penicillin/streptomycin and dexamethasone on anodized nanotubular titanium improved osteoblast numbers after 2 days of culture compared to uncoated unanodized titanium. In addition, results showed that depositing such drugs in SBF on anodized titanium was a more efficient method to promote osteoblast numbers compared to physical adsorption for up to 2 days of culture. In addition, osteoblast numbers increased on anodized titanium coated with drugs in SBF for up to 2 days of culture compared to unanodized titanium. In summary, compared to unanodized titanium, this preliminary study provided unexpected evidence of greater osteoblast numbers on anodized titanium coated with either penicillin/streptomycin or dexamethasone using simple physical adsorption or when coated with SBF; results which suggest the need for further research on anodized titanium orthopedic implants possessing drug-eluting nanotubes.

  2. Tribocorrosion behaviour of anodic treated titanium surfaces intended for dental implants

    Science.gov (United States)

    Alves, A. C.; Oliveira, F.; Wenger, F.; Ponthiaux, P.; Celis, J.-P.; Rocha, L. A.

    2013-10-01

    Tribocorrosion plays an important role in the lifetime of metallic implants. Once implanted, biomaterials are subjected to micro-movements in aggressive biological fluids. Titanium is widely used as an implant material because it spontaneously forms a compact and protective nanometric thick oxide layer, mainly TiO2, in ambient air. That layer provides good corrosion resistance, and very low toxicity, but its low wear resistance is a concern. In this work, an anodizing treatment was performed on commercial pure titanium to form a homogeneous thick oxide surface layer in order to provide bioactivity and improve the biological, chemical and mechanical properties. Anodizing was performed in an electrolyte containing β-glycerophosphate and calcium acetate. The influence of the calcium acetate content on the tribocorrosion behaviour of the anodized material was studied. The concentration of calcium acetate in the electrolyte was found to largely affect the crystallographic structure of the resulting oxide layer. Better tribocorrosion behaviour was noticed on increasing the calcium acetate concentration.

  3. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features.

    Science.gov (United States)

    Rajyalakshmi, Amancherla; Ercan, Batur; Balasubramanian, K; Webster, Thomas J

    2011-01-01

    One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti) leads to the formation of TiO(2) nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages) responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF) for 1 minute, nanotextured (nonnanotube) surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40-50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60-70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.

  4. ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.

    2008-01-01

    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  5. 二氧化钛纳米管阵列薄膜的超声辐射阳极氧化制备%Supersonic Anodization Preparation of Thin Titanium Oxide Nanotube Arrays Films

    Institute of Scientific and Technical Information of China (English)

    熊必涛; 朱志艳; 王长荣; 陈宝信; 骆钧炎

    2013-01-01

    通过使用铂片作为对电极在含有氢氟酸的二甲基亚砜溶液中,将金属钛片进行阳极氧化的方法制备得到二氧化钛纳米管阵列薄膜.在施加40 V偏压超声辐射作用下阳极氧化24 h条件下得到的二氧化钛纳米管长达到680nm,管内直径25 nm,管壁厚度约3~5 nm.采用了XRD和TEM等分析手段表征了二氧化钛纳米管阵列薄膜的微观结构和表面形貌,分别测试了薄膜的光吸收性能、循环伏安特性和光化学转换效率,并和碱性溶胶-凝胶方法制备的纳米晶二氧化钛薄膜作了对比研究.实验制备的二氧化钛纳米管阵列薄膜电极的光吸收率比纳米晶二氧化钛薄膜提高了40%,光电化学转换效率前者是后者的6倍,实验结果表明二氧化钛纳米管阵列薄膜结构有利于加快电子的传输,并能减少电荷复合,采用这种二氧化钛纳米管阵列薄膜结构的染料敏化太阳能电池光电极有望进一步提高太阳能电池的效率.本文还探讨了在超声波辐射作用下二氧化钛纳米管阵列薄膜的形成机理.%Thin titanium oxide nanotube arrays (TNAs) films were synthesized by supersonic anodization of titanium foil in an aqueous dimethyl sulfoxide solution containing HE After anodization, TNAs up to 680 nm in length, 25 nm inner pore diameter, and 3~5 nm wall thickness were obtained. Their microstructure and surface morphologies were characterized by XRD and TEM. The optical absorption performances, cyclic voltammograms characteristics and light chemical conversion efficiencies of these films were tested. The results implied that the TNAs films have an outstanding accelerated electronic transportation and compressed recombination rate. Electrodes applying such kind of titania nanotubes will have a potential to further enhance the TNAs-based dye-sensitized solar cells efficiencies. The sonoelectrochemical mechanism of TNAs films formation was discussed along with the characterization and

  6. Enhanced osteoblast adhesion to drug-coated anodized nanotubular titanium surfaces

    Directory of Open Access Journals (Sweden)

    George E Aninwene II

    2008-06-01

    Full Text Available George E Aninwene II1, Chang Yao2, Thomas J Webster21Department of Biochemical Engineering, University of Maryland, Baltimore, MD; 2Division of Engineering, Brown University, Providence, RI, USAAbstract: Current orthopedic implants have functional lifetimes of only 10–15 years due to a variety of reasons including infection, extensive inflammation, and overall poor osseointegration (or a lack of prolonged bonding of the implant to juxtaposed bone. To improve properties of titanium for orthopedic applications, this study anodized and subsequently coated titanium with drugs known to reduce infection (penicillin/streptomycin and inflammation (dexamethasone using simple physical adsorption and the deposition of such drugs from simulated body fluid (SBF. Results showed improved drug elution from anodized nanotubular titanium when drugs were coated in the presence of SBF for up to 3 days. For the first time, results also showed that the simple physical adsorption of both penicillin/streptomycin and dexamethasone on anodized nanotubular titanium improved osteoblast numbers after 2 days of culture compared to uncoated unanodized titanium. In addition, results showed that depositing such drugs in SBF on anodized titanium was a more efficient method to promote osteoblast numbers compared to physical adsorption for up to 2 days of culture. In addition, osteoblast numbers increased on anodized titanium coated with drugs in SBF for up to 2 days of culture compared to unanodized titanium. In summary, compared to unanodized titanium, this preliminary study provided unexpected evidence of greater osteoblast numbers on anodized titanium coated with either penicillin/streptomycin or dexamethasone using simple physical adsorption or when coated with SBF; results which suggest the need for further research on anodized titanium orthopedic implants possessing drug-eluting nanotubes.Keywords: anodization, titanium, adhesion, simulated body fluid, nanotubes

  7. Enhanced osteoblast functions on anodized titanium with nanotube-like structures.

    Science.gov (United States)

    Yao, Chang; Slamovich, Elliott B; Webster, Thomas J

    2008-04-01

    Previous studies have demonstrated increased osteoblast (bone-forming cells) adhesion on titanium and Ti-6Al-4V anodized to possess nanometer features compared with their unanodized counterparts. In this study, osteoblast long-term functions (specifically, synthesis of intracellular proteins, synthesis of intracellular collagen, alkaline phosphatase activity, and deposition of calcium-containing minerals) were determined on titanium anodized to possess either heterogeneous nanoparticles or ordered nanotubes. Titanium was anodized in dilute hydrofluoric acid at 20 V for 20 min to possess nanotubes, while titanium was anodized at 10 V for 20 min to possess nanoparticles. Most importantly, results showed that calcium deposition significantly increased on anodized titanium with nanotube-like structures compared with unanodized titanium and anodized titanium with nanoparticulate structures after 21 days of osteoblast culture. In this manner, the results of the present in vitro study indicated that anodization might be a promising quick and inexpensive method to modify the surface of titanium-based implants to induce better bone cell functions important for orthopedic applications.

  8. Histomorphometric and histologic evaluation of titanium-zirconium (aTiZr) implants with anodized surfaces.

    Science.gov (United States)

    Sharma, Ajay; McQuillan, A James; Shibata, Yo; Sharma, Lavanya A; Waddell, John Neil; Duncan, Warwick John

    2016-05-01

    The choice of implant surface has a significant influence on osseointegration. Modification of TiZr surface by anodization is reported to have the potential to modulate the osteoblast cell behaviour favouring more rapid bone formation. The aim of this study is to investigate the effect of anodizing the surface of TiZr discs with respect to osseointegration after four weeks implantation in sheep femurs. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy and goniometry. Forty implant discs with thickness of 1.5 and 10 mm diameter (10 of each-titanium, titanium-zirconium, anodized titanium and anodized titanium-zirconium) were placed in the femoral condyles of 10 sheep. Histomorphometric and histologic analysis were performed 4 weeks after implantation. The anodized implants displayed hydrophilic, porous, nano-to-micrometer scale roughened surfaces. Energy dispersive spectroscopy analysis revealed calcium and phosphorous incorporation into the surface of both titanium and titanium-zirconium after anodization. Histologically there was new bone apposition on all implanted discs, slightly more pronounced on anodised discs. The percentage bone-to-implant contact measurements of anodized implants were higher than machined/unmodified implants but there was no significant difference between the two groups with anodized surfaces (P > 0.05, n = 10). The present histomorphometric and histological findings confirm that surface modification of titanium-zirconium by anodization is similar to anodised titanium enhances early osseointegration compared to machined implant surfaces.

  9. Colorful titanium oxides: a new class of photonic materials

    Science.gov (United States)

    Li, Zhenzhen; Xin, Yanmei; Zhang, Zhonghai

    2015-11-01

    In this communication, a new class of photonic materials, namely, two-dimensional titanium oxide-based photonic crystals, are proposed and were fabricated with an electrochemical anodization method. The high structural periodicity of the nanostructures, and the feasible variability of the chemical compositions help to realize tunable photonic bandgaps for selective light absorption in broad wavelength regions.In this communication, a new class of photonic materials, namely, two-dimensional titanium oxide-based photonic crystals, are proposed and were fabricated with an electrochemical anodization method. The high structural periodicity of the nanostructures, and the feasible variability of the chemical compositions help to realize tunable photonic bandgaps for selective light absorption in broad wavelength regions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05374a

  10. Electrocatalytic properties and stability of titanium anodes activated by the inorganic sol–gel procedure

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2008-10-01

    Full Text Available The properties of activated titanium anodes, RuO2–TiO2/Ti and RuO2–TiO2–IrO2/Ti, prepared from oxide sols by the sol–gel procedure, are reviewed. RuO2 and TiO2 sols were synthesized by forced hydrolysis of the corresponding chlorides in acid medium. The morphology of the prepared sols was investigated by transmission electron microscopy. The chemical composition of the RuO2 sol was determined by X-ray diffraction and thermogravimetric analysis. The loss of electrocatalytic activity of a RuO2–TiO2/Ti anode during an accelerated stability test was investigated by examination of the changes in the electrochemical characteristics in the potential region of the chlorine and oxygen evolution reaction, as well as on the open circuit potential. These electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and polarization measurements. The changes in electrochemical characteristics of the anode prepared by the sol–gel procedure were compared to the changes registered for an anode prepared by the traditional thermal decomposition of metal chlorides. The comparison indicated that the main cause for the activity loss of the sol–gel prepared anode was the electrochemical dissolution of RuO2, while in the case of thermally prepared anode the loss was mainly caused by the formation of an insulating TiO2 layer in the coating/Ti substrate interphase. The results of an accelerated stability test on RuO2–TiO2/Ti and RuO2–TiO2–IrO2/Ti anodes showed that the ternary coating is considerably more stable than the binary one, which is the consequence of the greater stability of IrO2 in comparison to RuO2.

  11. Nanostructures Using Anodic Aluminum Oxide

    Science.gov (United States)

    Valmianski, Ilya; Monton, Carlos M.; Pereiro, Juan; Basaran, Ali C.; Schuller, Ivan K.

    2013-03-01

    We present two fabrication methods for asymmetric mesoscopic dot arrays over macroscopic areas using anodic aluminum oxide templates. In the first approach, metal is deposited at 45o to the template axis to partially close the pores and produce an elliptical shadow-mask. In the second approach, now underway, nanoimprint lithography on a polymer intermediary layer is followed by reactive ion etching to generate asymmetric pore seeds. Both these techniques are quantified by an analysis of the lateral morphology and lattice of the pores or dots using scanning electron microscopy and a newly developed MATLAB based code (available for free download at http://ischuller.ucsd.edu). The code automatically provides a segmentation of the measured area and the statistics of morphological properties such as area, diameter, and eccentricity, as well as the lattice properties such as number of nearest neighbors, and unbiased angular and radial two point correlation functions. Furthermore, novel user defined statistics can be easily obtained. We will additionally present several applications of these methods to superconducting, ferromagnetic, and organic nanostructures. This work is supported by AFOSR FA9550-10-1-0409

  12. Investigation of the mechanical and chemical characteristics of nanotubular and nano-pitted anodic films on grade 2 titanium dental implant materials.

    Science.gov (United States)

    Weszl, Miklós; Tóth, Krisztián László; Kientzl, Imre; Nagy, Péter; Pammer, Dávid; Pelyhe, Liza; Vrana, Nihal E; Scharnweber, Dieter; Wolf-Brandstetter, Cornelia; Joób F, Árpád; Bognár, Eszter

    2017-09-01

    The objective of this study was to investigate the reproducibility, mechanical integrity, surface characteristics and corrosion behavior of nanotubular (NT) titanium oxide arrays in comparison with a novel nano-pitted (NP) anodic film. Surface treatment processes were developed to grow homogenous NT and NP anodic films on the surface of grade 2 titanium discs and dental implants. The effect of process parameters on the surface characteristics and reproducibility of the anodic films was investigated and optimized. The mechanical integrity of the NT and NP anodic films were investigated by scanning electron microscopy, surface roughness measurement, scratch resistance and screwing tests, while the chemical and physicochemical properties were investigated in corrosion tests, contact angle measurement and X-ray photoelectron spectroscopy (XPS). The growth of NT anodic films was highly affected by process parameters, especially by temperature, and they were apt to corrosion and exfoliation. In contrast, the anodic growth of NP film showed high reproducibility even on the surface of 3-dimensional screw dental implants and they did not show signs of corrosion and exfoliation. The underlying reason of the difference in the tendency for exfoliation of the NT and NP anodic films is unclear; however the XPS analysis revealed fluorine dopants in a magnitude larger concentration on NT anodic film than on NP surface, which was identified as a possible causative. Concerning other surface characteristics that are supposed to affect the biological behavior of titanium implants, surface roughness values were found to be similar, whereas considerable differences were revealed in the wettability of the NT and NP anodic films. Our findings suggest that the applicability of NT anodic films on the surface of titanium bone implants may be limited because of mechanical considerations. In contrast, it is worth to consider the applicability of nano-pitted anodic films over nanotubular arrays

  13. Biophotofuel cell anode containing self-organized titanium dioxide nanotube array

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Yong X., E-mail: yong.gan@utoledo.edu [Mechanical, Industrial and Manufacturing Engineering, College of Engineering, University of Toledo, 2801 W Bancroft Street, Toledo, OH 43606 (United States); Gan, Bo J. [Ottawa Hills High School, 2532 Evergreen Road, Toledo, OH 43606 (United States); Su Lusheng [Mechanical, Industrial and Manufacturing Engineering, College of Engineering, University of Toledo, 2801 W Bancroft Street, Toledo, OH 43606 (United States)

    2011-09-15

    Graphical abstract: Highlights: {center_dot} A photoactive anode containing highly ordered TiO{sub 2} nanotube array was made and the formation mechanism of self-organized TiO{sub 2} nanotube array on Ti was revealed. {center_dot} Effect of electrolyte concentration and voltage on the size distribution of the nanotubes was investigated. {center_dot} Self-organized TiO{sub 2} nanotube array anode possesses good photo-catalytic behavior of biomass decomposition under ultraviolet (UV) radiation. {center_dot} The fuel cell generates electricity and hydrogen via photoelectrochemical decomposition of ethanol, apple vinegar, sugar and tissue paper. - Abstract: We made a biophotofuel cell consisting of a titanium dioxide nanotube array photosensitive anode for biomass decomposition, and a low-hydrogen overpotential metal, Pt, as the cathode for hydrogen production. The titanium dioxide nanotubes (TiO{sub 2} NTs) were prepared via electrochemical oxidation of pure Ti in NaF solutions. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO{sub 2} NTs were 88 {+-} 16 nm, 10 {+-} 2 nm and 491 {+-} 56 nm, respectively. Such dimensions are affected by the NaF concentration and the applied voltage during processing. Higher NaF concentrations result in the formation of longer and thicker nanotubes. The higher the voltage is, the thicker the nanotubes. The photosensitive anode made from the highly ordered TiO{sub 2} NTs has good photo-catalytic property, as can be seen from the test results of ethanol, apple vinegar, sugar and tissue paper decomposition under ultraviolet (UV) radiation. It is concluded that the biophotofuel cell with the TiO{sub 2} nanotube photoanode and a Pt cathode can generate electricity, hydrogen and clean water depending on the pH value and the oxygen presence in the solutions.

  14. Surface integrity after pickling and anodization of Ti-6Al-4V titanium alloy

    Science.gov (United States)

    Vermesse, Eric; Mabru, Catherine; Arurault, Laurent

    2013-11-01

    The surface integrity of Ti-6Al-4V titanium alloy was studied at different stages of surface treatments, especially pickling and compact anodization, through surface characteristics potentially worsening fatigue resistance.

  15. Effect of amorphous fluorinated coatings on photocatalytic properties of anodized titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Persico, Federico [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Sansotera, Maurizio, E-mail: maurizio.sansotera@polimi.it [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Diamanti, Maria Vittoria [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Magagnin, Luca; Venturini, Francesco; Navarrini, Walter [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy)

    2013-10-31

    The photocatalytic activity promoted by anodized titanium surfaces coated with different amorphous perfluoropolymers was evaluated. A copolymer between tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole and two perfluoropolyethers containing ammonium phosphate and triethoxysilane functionalities, respectively, were tested as coating materials. These coatings revealed good adhesion to the anodized titanium substrate and conferred to it both hydrophobicity and oleophobicity. The photocatalytic activity of the coating on anodized titanium was evaluated by monitoring the degradation of stearic acid via Infrared spectroscopy. The degradation rate of stearic acid was reduced but not set to zero by the presence of the fluorinated coatings, leading to the development of advanced functional coatings. The morphological variations of the coatings as a result of photocatalysis were also determined by atomic force microscopy. - Highlights: • Coated anodized titanium surfaces show a decreased wettability. • Evaluation of the stability of perfluorinated coatings towards photocatalysis. • Amorphous perfluorinated coatings do not hinder photocatalytic activity.

  16. Synthesis by anodic-spark deposition of Ca- and P-containing films on pure titanium and their biological response

    Energy Technology Data Exchange (ETDEWEB)

    Banakh, Oksana, E-mail: oksana.banakh@he-arc.ch [Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Journot, Tony; Gay, Pierre-Antoine; Matthey, Joël; Csefalvay, Catherine [Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Kalinichenko, Oleg [Ukrainian State University of Chemical Technology (SHEI), Gagarin av. 8, Dnepropetrovsk, UA-49005 (Ukraine); Sereda, Olha [Centre Suisse d’Electronique et de Microtechnique (CSEM), Rue Jaquet-Droz 1, CH-2000 Neuchâtel (Switzerland); Moussa, Mira; Durual, Stéphane [Laboratory of Biomaterials, University of Geneva, rue Barthelemy Menn 19, CH-1205 Geneva (Switzerland); Snizhko, Lyubov [Ukrainian State University of Chemical Technology (SHEI), Gagarin av. 8, Dnepropetrovsk, UA-49005 (Ukraine)

    2016-08-15

    Highlights: • ​CP-4 Ti was treated by anodic spark oxidation in the electrolyte containing Ca and P ions by varying process time and electrolyte concentration. • Ca/P ratio in layers is 0.23–0.47, much lower than in hydroxyapatites (1.67). It means coatings should be resorbable in a biological medium • After immersion in SBF, Ca and P content in layers decrease. Ca and P loss occurs faster in thin layers than in thicker coatings. • The biological response of the samples suggests their excellent biocompatibility and even stimulating effects on osteoblasts proliferation. - Abstract: The purpose of this work is to characterize the anodized layers formed on titanium by anodic-spark deposition in an electrolyte containing Ca and P ions, Ca{sub 3}(PO{sub 4}){sub 2}, studied for the first time. The oxidation experiments were performed at different periods of time and using different concentrations of electrolyte. The influence of the process parameters (time of electrolysis and electrolyte concentration) on the surface morphology and chemical composition of the anodized layers was studied. It has been found that it is possible to incorporate Ca and P into the growing layer. A response of the anodized layers in a biological medium was evaluated by their immersion in a simulated body fluid. An enrichment of titanium and a simultaneous loss of calcium and phosphorus in the layer after immersion tests indicate that these coatings should be bioresorbable in a biological medium. Preliminary biological assays were performed on some anodized layers in order to assess their biocompatibility with osteoblast cells. The cell proliferation on one selected anodized sample was assessed up to 21 days after seeding. The preliminary results suggest excellent biocompatibility properties of anodized coatings.

  17. Interfacial oxidations of pure titanium and titanium alloys with investments.

    Science.gov (United States)

    Ban, S; Watanabe, T; Mizutani, N; Fukui, H; Hasegawa, J; Nakamura, H

    2000-12-01

    External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface.

  18. Microfabrication of an anodic oxide film by anodizing laser-textured aluminium

    OpenAIRE

    2007-01-01

    A simple method for the fabrication of microstructures of an aluminium anodic oxide film (anodic alumina) by anodizing laser-textured aluminium is demonstrated. In the process, the aluminium substrate was first textured by a low power laser beam, and then the textured aluminium was subjected to anodizing, to develop a continuous, thick porous layer on the textured surface. Microstructures with a depth of a few to several tens of micrometres were fabricated successfully on the anodic oxide fil...

  19. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium.

    Science.gov (United States)

    Amin Yavari, S; Chai, Y C; Böttger, A J; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2015-06-01

    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium.

  20. Improved in vitro angiogenic behavior on anodized titanium dioxide nanotubes.

    Science.gov (United States)

    Beltrán-Partida, Ernesto; Valdéz-Salas, Benjamín; Moreno-Ulloa, Aldo; Escamilla, Alan; Curiel, Mario A; Rosales-Ibáñez, Raúl; Villarreal, Francisco; Bastidas, David M; Bastidas, José M

    2017-01-31

    Neovascularization over dental implants is an imperative requisite to achieve successful osseointegration onto implanted materials. The aim of this study was to investigate the effects on in vitro angiogenesis of anodized 70 nm diameter TiO2 nanotubes (NTs) on Ti6Al4V alloy synthesized and disinfected by means of a novel, facile, antibacterial and cost-effective method using super oxidized water (SOW). We also evaluated the role of the surface roughness and chemical composition of materials of materials on angiogenesis. The Ti6Al4V alloy and a commercially pure Ti were anodized using a solution constituted by SOW and fluoride as electrolyte. An acid-etched Ti6Al4V was evaluated to compare the effect of micro-surface roughness. Mirror-polished materials were used as control. Morphology, roughness, chemistry and wettability were assessed by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy (EDX) and using a professional digital camera. Bovine coronary artery endothelial cells (BCAECs) were seeded over the experimental surfaces for several incubation times. Cellular adhesion, proliferation and monolayer formation were evaluated by means of SEM. BCAEC viability, actin stress fibers and vinculin cellular organization, as well as the angiogenic receptors vascular endothelial growth factor 2 (VEGFR2) and endothelial nitric oxide synthase (eNOS) were measured using fluorescence microscopy. The anodization process significantly increased the roughness, wettability and thickness of the oxidized coating. EDX analysis demonstrated an increased oxygen (O) and decreased carbon (C) content on the NTs of both materials. Endothelial behavior was solidly supported and improved by the NTs (without significant differences between Ti and alloy), showing that endothelial viability, adhesion, proliferation, actin arrangement with vinculin expression and monolayer development were

  1. Oxide anode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fergus, Jeffrey W. [Auburn University, Materials Research and Education Center, 275 Wilmore Laboratories, Auburn, AL 36849 (United States)

    2006-07-15

    A major advantage of solid oxide fuel cells (SOFCs) over polymer electrolyte membrane (PEM) fuel cells is their tolerance for the type and purity of fuel. This fuel flexibility is due in large part to the high operating temperature of SOFCs, but also relies on the selection and development of appropriate materials - particularly for the anode where the fuel reaction occurs. This paper reviews the oxide materials being investigated as alternatives to the most commonly used nickel-YSZ cermet anodes for SOFCs. The majority of these oxides form the perovskite structure, which provides good flexibility in doping for control of the transport properties. However, oxides that form other crystal structures, such as the cubic fluorite structure, have also shown promise for use as SOFC anodes. In this paper, oxides are compared primarily in terms of their transport properties, but other properties relative to SOFC anode performance are also discussed. (author)

  2. Optical Transmittance of Anodically Oxidized Aluminum Alloy

    Science.gov (United States)

    Saito, Mitsunori; Shiga, Yasunori; Miyagi, Mitsunobu; Wada, Kenji; Ono, Sachiko

    1995-06-01

    Optical transmittance and anisotropy of anodic oxide films that were made from pure aluminum and an aluminum alloy (A5052) were studied. The alloy oxide film exhibits an enhanced polarization function, particularly when anodization is carried out at a large current density. It was revealed by chemical analysis that the alloy oxide film contains a larger amount of unoxidized aluminum than the pure-aluminum oxide film. The polarization function can be elucidated by considering unoxidized aluminum particles that are arranged in the columnar structure of the alumina film. Electron microscope observation showed that many holes exist in the alloy oxide film, around which columnar cells are arranged irregularly. Such holes and irregular cell arrangement cause the increase in the amount of unoxidized aluminum, and consequently induces scattering loss.

  3. Preparation and crystalline phase of a TiO2 porous film by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; ZHANG Weiwei; TAO Haijun; WANG Ling

    2005-01-01

    Anatase titanium dioxide is an active photocatalyst, but it is difficult to immobilize on the substrate. A crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation in this work. Constant voltage and constant current anodic oxidation were adopted with sulphuric acid used as the electrolyte, pure titanium as the anode and copper as the cathode. The morphology and structure of the porous film on the substrate were analyzed with the aid of Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD). The effects of the parameters of anodic oxidation (such as voltage, the concentration of sulphuric acid, anodization time and current density) on the aperture and the crystalline phase of the TiO2 porous film were systematically investigated. The results indicate that the increase of current density facilitates the augment of the aperture and the generation of anatase and rutile. In addition, the forming mechanism of anatase and rutile TiO2 porous films was discussed.

  4. In vitro investigation of anodization and CaP deposited titanium surface using MG63 osteoblast-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.M. [Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongno-gu, Seoul 110-749 (Korea, Republic of); Lee, J.I. [Department of Oral Pathology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Lim, Y.J., E-mail: limdds@snu.ac.kr [Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongno-gu, Seoul 110-749 (Korea, Republic of)

    2010-03-01

    The aim of the present study was to investigate surface characteristics in four different titanium surfaces (AN: anodized at 270 V; AN-CaP: anodic oxidation and CaP deposited; SLA: sandblasted and acid etched; MA: machined) and to evaluate biological behaviors such as cell adhesion, cell proliferation, cytoskeletal organization, and osteogenic protein expression of MG63 osteoblast-like cells at the early stage. Surface analysis was performed using scanning electron microscopy, thin-film X-ray diffractometry, and a confocal laser scanning microscope. In order to evaluate cellular responses, MG63 osteoblast-like cells were used. The cell viability was evaluated by MTT assay. Immunofluorescent analyses of actin, type I collagen, osteonectin and osteocalcin were performed. The anodized and CaP deposited specimen showed homogeneously distributed CaP particles around micropores and exhibited anatase type oxides, titanium, and HA crystalline structures. This experiment suggests that CaP particles on the anodic oxidation surface affect cellular attachment and spreading. When designing an in vitro biological study for CaP coated titanium, it must be taken into account that preincubation in medium prior to cell seeding and the cell culture medium may affect the CaP coatings. All these observations illustrate the importance of the experimental conditions and the physicochemical parameters of the CaP coating. It is considered that further evaluations such as long-term in vitro cellular assays and in vivo experiments should be necessary to figure out the effect of CaP deposition to biological responses.

  5. Ellipsometric investigation of anodic zirconium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Patrito, E.M.; Macagno, V.A. (Univ. Nacional de Cordoba, Cordoba (Argentina). Dept. de Fisicoquimica)

    1993-06-01

    The anodic oxidation of zirconium was studied by in situ ellipsometry together with capacity measurements. The oxides were grown under potentiodynamic, galvanostatic, and potentiostatic conditions up to final potentials of 100 V in 0.5M H[sub 2]SO[sub 4] solution. The refractive index of the oxides changes depending on the growth current. The films were slightly absorbing but their absorption coefficient was independent of the oxide growth conditions. Different methods of surface preparation including etching in hydrofluoric acid-based mixtures, electropolishing and mechanical polishing were used. The surfaces and oxides were characterized by SEM examination and XPS measurements. The surface pretreatment affects both the substrate and the oxide optical constants as well as the rate of oxide growth. The density and dielectric constant of the oxides were calculated performing simultaneous ellipsometric, coulometric, and capacity measurements.

  6. Fabrication of anodic aluminum oxide with incorporated chromate ions

    Science.gov (United States)

    Stępniowski, Wojciech J.; Norek, Małgorzata; Michalska-Domańska, Marta; Bombalska, Aneta; Nowak-Stępniowska, Agata; Kwaśny, Mirosław; Bojar, Zbigniew

    2012-10-01

    The anodization of aluminum in 0.3 M chromic acid is studied. The influence of operating conditions (like anodizing voltage and electrolyte's temperature) on the nanoporous anodic aluminum oxide geometry (including pore diameter, interpore distance, the oxide layer thickness and pores density) is thoroughly investigated. The results revealed typical correlations of the anodic alumina nanopore geometry with operating conditions, such as linear increase of pore diameter and interpore distance with anodizing voltage. The anodic aluminum oxide is characterized by a low pores arrangement, as determined by Fast Fourier transforms analyses of the FE-SEM images, which translates into a high concentration of oxygen vacancies. Moreover, an optimal experimental condition where chromate ions are being successfully incorporated into the anodic alumina walls, have been determined: the higher oxide growth rate the more chromate ions are being trapped. The trapped chromate ions and a high concentration of oxygen vacancies make the anodic aluminum oxide a promising luminescent material.

  7. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium

    Energy Technology Data Exchange (ETDEWEB)

    Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Chai, Y.C. [Prometheus, Division of Skeletal Tissue Engineering, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); 3D Systems — LayerWise NV, Grauwmeer 14, 3001 Leuven (Belgium); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 — PB2450, B-3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Dept. Rheumatology, UMC Utrecht, Heidelberglaan100, 3584CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2015-06-01

    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20 V anodizing time: 30 min to 3 h) are used for anodizing porous titanium structures that were later heat treated at 500 °C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55 nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500 °C improve the cell culture response of porous titanium

  8. Increasing Wear Resistance of Titanium Alloys by Anode Plasma Electrolytic Saturation with Interstitial Elements

    Science.gov (United States)

    Belkin, P. N.; Kusmanov, S. A.; Dyakov, I. G.; Silkin, S. A.; Smirnov, A. A.

    2017-05-01

    In our previous studies, we have shown that anode plasma electrolytic saturation of titanium alloys with nitrogen and carbon can improve their tribological properties. Obtained structure containing oxide layer and solid solution of diffused element in titanium promotes the enhancement of running-in ability and the decrease in the wear rate in some special cases. In this paper, further investigations are reported regarding the tribological properties of alpha- and beta-titanium alloys in wear test against hardened steel (50 HRC) disk using pin-on-disk geometry and balls of Al2O3 (6.25 mm in diameter) or bearing steel (9.6 mm in diameter) with ball-on-plate one and normal load from 5 to 209 N. Reproducible results were obtained under testing samples treated by means of the plasma electrolytic nitriding (PEN) with the mechanical removal of the oxide layer. Friction coefficient of nitrided samples is 0.5-0.9 which is somewhat higher than that for untreated one (0.48-0.75) during dry sliding against Al2O3 ball. An increase in the sliding speed results in the polishing of nitrided samples and reduction of their wear rate by 60 times. This result is obtained for 5 min at 850 °C using PEN in electrolyte containing 5 wt.% ammonia and 10 wt.% ammonium chloride followed by quenching in solution. Optical microscope was employed to assist in the evaluation of the wear behavior. Sizes of wear tracks were measured by profilometer TR200.

  9. Amorphous titanium-oxide supercapacitors

    Science.gov (United States)

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2016-10-01

    The electric capacitance of an amorphous TiO2-x surface increases proportionally to the negative sixth power of the convex diameter d. This occurs because of the van der Waals attraction on the amorphous surface of up to 7 mF/cm2, accompanied by extreme enhanced electron trapping resulting from both the quantum-size effect and an offset effect from positive charges at oxygen-vacancy sites. Here we show that a supercapacitor, constructed with a distributed constant-equipment circuit of large resistance and small capacitance on the amorphous TiO2-x surface, illuminated a red LED for 37 ms after it was charged with 1 mA at 10 V. The fabricated device showed no dielectric breakdown up to 1,100 V. Based on this approach, further advances in the development of amorphous titanium-dioxide supercapacitors might be attained by integrating oxide ribbons with a micro-electro mechanical system.

  10. Laser induced single spot oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jwad, Tahseen, E-mail: taj355@bham.ac.uk; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-30

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  11. Surface integrity after pickling and anodization of Ti–6Al–4V titanium alloy

    OpenAIRE

    Vermesse, Eric; Mabru, Catherine; Arurault, Laurent

    2013-01-01

    International audience; The surface integrity of Ti–6Al–4V titanium alloy was studied at different stages of surface treatments, especially pickling and compact anodization, through surface characteristics potentially worsening fatigue resistance. No significant changes of the equiaxe microstructure were detected between sample core and surface, or after the pickling and anodization steps. Surface hydrogen and oxygen superficial contents were found to remain unchanged. Roughness characteristi...

  12. Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium.

    Science.gov (United States)

    Lee, Woo; Schwirn, Kathrin; Steinhart, Martin; Pippel, Eckhard; Scholz, Roland; Gösele, Ulrich

    2008-04-01

    Nanoporous anodic aluminium oxide has traditionally been made in one of two ways: mild anodization or hard anodization. The first method produces self-ordered pore structures, but it is slow and only works for a narrow range of processing conditions; the second method, which is widely used in the aluminium industry, is faster, but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the mild and hard anodization processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic aluminium oxide films while maintaining high throughput. We use pulse anodization to delaminate a single as-prepared anodic film into a stack of well-defined nanoporous alumina membrane sheets, and also to fabricate novel three-dimensional nanostructures.

  13. Laser induced single spot oxidation of titanium

    Science.gov (United States)

    Jwad, Tahseen; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-01

    Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels' colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  14. Characterization of Micro-arc Oxidized Titanium

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The observation of the sparkling discharges during the micro-arc oxidation process in KOH aqueous electrolyte was achieved. The change of surface morphology was progressively observed and a plausible pore formation mechanism is proposed. Cell proliferation and ALP activity of micro-arc oxidized titanium was evaluated by human body derived osteoblasts and slightly better than those of blasted surface.

  15. Photoluminescence from Nd Doped Anodic Aluminium Oxide

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhang-Kai; PENG Xiao-Niu; SU Xiong-Rui; HAO Zhong-Hua

    2009-01-01

    We prepare Nd doped anodic aluminium oxide (Nd:AAO) template by using Nd doped aluminium foils through two-step anodization processes. Photoluminescence (PL) from the Nd:AAO template with the annealing temper-ature higher than 400℃ is observed, and the PL intensity enhanced with the increasing annealing temperature is found. We investigate the crystallization of Nd:AAO template and the excitation wavelength dependence of PL intensity, showing that the PL results from the Nd doped in the template. The approach presented may probably facilitate the fabricating of AAO with good light-emitting property, which can be used in fabrication of multifunctional nanosized films and may find applications in photonic devices.

  16. Microbial Communities and Electrochemical Performance of Titanium-Based Anodic Electrodes in a Microbial Fuel Cell

    NARCIS (Netherlands)

    Michaelidou, U.; Heijne, ter A.; Euverink, G.J.W.; Hamelers, H.V.M.; Stams, A.J.M.; Geelhoed, J.S.

    2011-01-01

    Four types of titanium (Ti)-based electrodes were tested in the same microbial fuel cell (MFC) anodic compartment. Their electrochemical performances and the dominant microbial communities of the electrode biofilms were compared. The electrodes were identical in shape, macroscopic surface area, and

  17. The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

    Science.gov (United States)

    Hu, Nan; Gao, Nong; Starink, Marco J.

    2016-11-01

    Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt.% NH4F for 2 h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

  18. Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2014-12-01

    The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

  19. Titanium doped LSCM anode for hydrocarbon fuelled SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Abul K.; Hakem, Afizul; Petra, Pg. M. Iskandar [Faculty of Integrated Technologies, Universiti Brunei Darussalam, Gadong BE 1410 (Brunei Darussalam)

    2015-05-15

    La{sub 0.75}Sr{sub 0.25}Cr{sub 0.5-x}Mn{sub 0.5}Ti{sub x}O{sub 3} (x = 0.1, 0.2) has been synthesized in solid state reaction method and tested as a potential anode material for solid oxide fuel cells. Rietveld refinement of X-ray powder diffraction data using Fullprof software shows that the materials crystallize in the rhombohedral symmetry in the R-3C space group. The cell parameters are: a = b = 5.5286 (4) Å, c = 13.408(1) Å, α = β = 90°, γ = 120°. Particle size distribution measurements show that the average particle size for x = 0.1 and 0.2 was 232.66 nm and 176.63 nm, respectively. The potential on particles were found to be −22.86 mV and −27.73 mV, for x = 0.1 and x = 0.2, respectively. Thermal expansion measurement using thermo-mechanical analyzer shows that the thermal expansion coefficient is 13.96 × 10{sup −6}/°C which is close to the thermal expansion of the state-of–the art YSZ electrolyte. Microstructure has been observed from scanning electron microscopy which shows a porous structure. Energy dispersive X-ray shows that the percentage of the different cations and anions in the structure are close to the chemical occupancies.

  20. Plasma synthesis of titanium nitride, carbide and carbonitride nanoparticles by means of reactive anodic arc evaporation from solid titanium

    Energy Technology Data Exchange (ETDEWEB)

    Kiesler, D., E-mail: dennis.kiesler@uni-due.de; Bastuck, T.; Theissmann, R.; Kruis, F. E. [University of Duisburg-Essen, Institute of Technology for Nanostructures (NST) and Center for Nanointegration Duisburg-Essen (CENIDE) (Germany)

    2015-03-15

    Plasma methods using the direct evaporation of a transition metal are well suited for the cost-efficient production of ceramic nanoparticles. In this paper, we report on the development of a simple setup for the production of titanium-ceramics by reactive anodic arc evaporation and the characterization of the aerosol as well as the nanopowder. It is the first report on TiC{sub X}N{sub 1 − X} synthesis in a simple anodic arc plasma. By means of extensive variations of the gas composition, it is shown that the composition of the particles can be tuned from titanium nitride over a titanium carbonitride phase (TiC{sub X}N{sub 1 − X}) to titanium carbide as proven by XRD data. The composition of the plasma gas especially a very low concentration of hydrocarbons around 0.2 % of the total plasma gas is crucial to tune the composition and to avoid the formation of free carbon. Examination of the particles by HR-TEM shows that the material consists mostly of cubic single crystalline particles with mean sizes between 8 and 27 nm.

  1. Synthesis and physicochemical characterization of titanium oxide and sulfated titanium oxide obtained by thermal hydrolysis of titanium tetrachloride

    Directory of Open Access Journals (Sweden)

    H. Esteban Benito

    2014-09-01

    Full Text Available This work reports the synthesis of titanium oxide (TiO2 and sulfated titanium oxide (TiO2-SO4(2- obtained by thermal hydrolysis of titanium tetrachloride. Titanium hydroxide synthesized by this method was impregnated with a 1 N H2SO4 solution, to give amounts of sulfate ions (SO4(2- of 3 and 7 wt%. The synthesized samples were dried at 120 °C during 24 h and then calcined for 3 h at 400 °C. Thermal analyses, X-ray diffraction, nitrogen physisorption, infrared spectroscopy, potentiometric titration with n-butylamine, U.V.-visible diffuse reflectance spectroscopy and scanning electron microscopy were used to characterize the materials. The results of physicochemical characterization revealed that a mixture of crystalline structures, anatase, brookite and rutile developed in the titanium oxide, stabilizing the anatase structure in the sulfated titanium oxides, and coexisting with a small amount of brookite structure. The synthesized mesoporous materials developed specific surface areas between 62 and 70 m² g-1, without detecting an important influence of sulfation on this parameter. The presence of sulfate ions improved the acidity of titanium oxide and modified the characteristics of light absorption in the 425-600 nm region, which suggests the possibility of using these materials in reactions assisted by visible light.

  2. Osteoblast response on co-modified titanium surfaces via anodization and electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Cem [Nanotechnology and Nanomedicine Division, Hacettepe University, Ankara, Beytepe, 06800 (Turkey); Chemistry Department, Aksaray University, Aksaray, 68100 (Turkey); Demirbilek, Murat; Yalçın, Eda [Nanotechnology and Nanomedicine Division, Hacettepe University, Ankara, Beytepe, 06800 (Turkey); Bozkurt, Murat; Doğan, Metin [Orthopaedics and Traumatology Division, Yıldırım Beyazıt University, School of Medicine, Cankaya, 06550 (Turkey); Denkbaş, Emir Baki, E-mail: denkbas@hacettepe.edu.tr [Chemistry Department, Hacettepe University, Ankara, Beytepe, 06800 (Turkey)

    2014-01-01

    Topography plays a key role in osseointegration and surface modifications at the subcellular level, increasing initial cell attachment in the early period. In the past decade, nanosized texture on metal like a nanotube layer and also more recently extracellular matrix like surface modifications – such as polymeric nanofibrils – have been proposed for a better osseointegration in the literature. Here, we investigate two types of nanoscaled modifications alone and together for the first time. We characterized different types of surface modifications morphologically and investigated how they affected osteoblast cells in vitro, in terms of cell adhesion, proliferation, alkaline phosphatase activity and calcium content. We anodized titanium samples with a thickness of 0.127 mm to obtain a nanotubular titania layer and the silk fibroin (SF), as a biocompatible polymeric material, was electrospun onto both anodized and unanodized samples to acquire 4 sample groups. We analyzed the resulting samples morphologically by scanning electron microscopy (SEM). Cell adhesion, proliferation, alkaline phosphatase (ALP) activity and calcium content were evaluated at 3, 7 and 14 days. We found that cell proliferation increased by 70% on the groups having two modifications respect to unmodified titanium and after 7 days, ALP activity and calcium content were 110% and 150%, respectively, higher on surfaces having both surface treatments than that of unmodified group. In conclusion, a nanotube layer and SF nanofibers on a titanium surface enhanced cell attachment and proliferation most. Comodification of titanium surfaces by anodization and SF electrospinning may be useful to enhance osseointegration but it requires in vivo confirmation.

  3. A new anode material for oxygen evolution in molten oxide electrolysis.

    Science.gov (United States)

    Allanore, Antoine; Yin, Lan; Sadoway, Donald R

    2013-05-16

    Molten oxide electrolysis (MOE) is an electrometallurgical technique that enables the direct production of metal in the liquid state from oxide feedstock, and compared with traditional methods of extractive metallurgy offers both a substantial simplification of the process and a significant reduction in energy consumption. MOE is also considered a promising route for mitigation of CO2 emissions in steelmaking, production of metals free of carbon, and generation of oxygen for extra-terrestrial exploration. Until now, MOE has been demonstrated using anode materials that are consumable (graphite for use with ferro-alloys and titanium) or unaffordable for terrestrial applications (iridium for use with iron). To enable metal production without process carbon, MOE requires an anode material that resists depletion while sustaining oxygen evolution. The challenges for iron production are threefold. First, the process temperature is in excess of 1,538 degrees Celsius (ref. 10). Second, under anodic polarization most metals inevitably corrode in such conditions. Third, iron oxide undergoes spontaneous reduction on contact with most refractory metals and even carbon. Here we show that anodes comprising chromium-based alloys exhibit limited consumption during iron extraction and oxygen evolution by MOE. The anode stability is due to the formation of an electronically conductive solid solution of chromium(iii) and aluminium oxides in the corundum structure. These findings make practicable larger-scale evaluation of MOE for the production of steel, and potentially provide a key material component enabling mitigation of greenhouse-gas emissions while producing metal of superior metallurgical quality.

  4. Anodized porous titanium coated with Ni-CeO2 deposits for enhancing surface toughness and wear resistance

    Science.gov (United States)

    Zhou, Xiaowei; Ouyang, Chun

    2017-05-01

    In order to make large improvements of surface toughness and wear resistance for pure titanium (Ti) substrate, anodic titanium oxide (ATO) surface with nanoporous structure was coated with the Ni-CeO2 nanocomposite coatings. Regarding TiO2 barrier layer on Ti surface to inhibit its electrochemical activity, pre-treatments were successively processed with anodizing, sensitizing, activating, and then followed by electroless Ni-P film to be acted as an activated layer for electroplating Ni-CeO2 deposits. The existing Pd atoms around ATO nanopores were expected as the heterogeneous nucleation sites for supporting the growing locations of electroless Ni-P film. The innovative of interface design using porous structure was introduced for bonding pinholes to achieve a metallurgical adhesion interface between Ti substrate and surface coatings. Besides the objectives of this work were to elucidate how effects by the adding CeO2 nanoparticles on modifying microstructures and wear mechanisms of Ni-CeO2 nanocomposite coatings. Many efforts of XRD, FE-SEM, TEM and Nanoindentation tests were devoted to comparing different wear behaviors of Ni-CeO2 coatings relative to pure nickel. Results indicated that uniform-distributed Ti nanopores with an average diameter size of ∼200 nm was achieved using the Phosphate-type anodizing solution at DC 150 V. A worn surface without fatigue cracks was observed for TAO surface coated with Ni-CeO2 deposits, showing the existing Ce-rich worn products to be acted as a solid lubricant phase for making a self-healing effect on de-lamination failures. More important, this finding will be the guidelines for Ce-rich precipitations to be expected as the strengthening phase in anodized porous of Ti, Al and Mg alloys for intensifying their surface properties.

  5. Surface characteristics of hydroxyapatite films deposited on anodized titanium by an electrochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang [Research Institute, Kuwotech, 970–88, Wolchul-dong, Buk-ku, Gwangju (Korea, Republic of); Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Jeong, Yong-Hoon; Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State, University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2013-11-01

    The biocompatibility of anodized titanium (Ti) was improved by an electrochemically deposited calcium phosphate (CaP) layer. The CaP layer was grown on the anodized Ti surface in modified simulated body fluid (M-SBF) at 85 °C. The phases and morphologies for the CaP layers were influenced by the electrolyte concentration. Nano flake-like precipitates that formed under low M-SBF concentrations were identified as hydroxyapatite (HAp) crystals orientated in the c-axis direction. In high M-SBF concentrations, the CaP layer formed micro plate-like precipitates on anodized Ti, and micropores were covered with HAp. Proliferation of murine preosteoblast cell (MC3T3-E1) on the HAp/anodized Ti surfaces was significantly higher than for untreated Ti and anodized Ti surfaces. - Highlights: • CaP layers were grown on anodized Ti surfaces by an electrochemical deposition process. • Phases and morphologies of layers were influenced by the electrolyte concentration. • Superior cell proliferation was observed on hydroxyapatite-coated anodized surfaces.

  6. Formation and Morphology of Anodic Oxide Films of Ti

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The morphology and structure of the oxide films of Ti in H3PO4 were investigated by galvanostatic anodization, SEM and XRD. The oxide film grew from some pores in the grooves to layered microdomains as increasing anodizing voltage. The crystallinity of the oxide films decreased with the increase of the concentration of the electrolyte. The model has been proposed for the growth of the oxide films by two steps, i.e. by uniform thickening and by local deposition.

  7. Structure and photocatalysis activity of silver doped titanium oxide nanotubes array for degradation of pollutants

    Science.gov (United States)

    Al-Arfaj, E. A.

    2013-10-01

    Semiconductor titanium oxide showed a wonderful performance as a photocatalysis for environmental remediation. Owing to high stability and promising physicochemical properties, titanium oxide nanostructures are used in various applications such as wastewater treatment, antimicrobial and air purification. In the present study, titanium oxide nanotubes and silver doped titanium oxide nanotubes were synthesized via anodic oxidation method. The morphology and composition structure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results depicted that nanotubes possess anatase phase with average tube diameter of 65 nm and 230 ± 12 nm in length. The band gap of the un-doped and silver doped titanium dioxide nanotubes was determined using UV-Vis. spectrophotometer. The results showed that the band gap of titanium dioxide nanotubes is decreased when doped with silver ions. The photocatalysis activity of un-doped and silver doped TiO2 nanotubes were evaluated in terms of degradation of phenol in the presence of ultra violet irradiation. It was found that silver doped TiO2 nanotubes exhibited much higher photocatalysis activity than un-doped TiO2 nanotubes.

  8. The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Nan; Gao, Nong, E-mail: N.Gao@soton.ac.uk; Starink, Marco J.

    2016-11-30

    Highlights: • HPT has substantially improved the UTS and Hv of pure Ti. • TNT layers was fabricated on UFG Ti made by HPT. • Influence of sample preparation on TNT layers was systematically studied. • Oxide dissolution was accelerated when TNTs formed on the HPT sample. - Abstract: Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt.% NH{sub 4}F for 2 h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

  9. Titanium Oxide: A Bioactive Factor in Osteoblast Differentiation

    Directory of Open Access Journals (Sweden)

    P. Santiago-Medina

    2015-01-01

    Full Text Available Titanium and titanium alloys are currently accepted as the gold standard in dental applications. Their excellent biocompatibility has been attributed to the inert titanium surface through the formation of a thin native oxide which has been correlated to the excellent corrosion resistance of this material in body fluids. Whether this titanium oxide layer is essential to the outstanding biocompatibility of titanium surfaces in orthopedic biomaterial applications is still a moot point. To study this critical aspect further, human fetal osteoblasts were cultured on thermally oxidized and microarc oxidized (MAO surfaces and cell differentiation, a key indicator in bone tissue growth, was quantified by measuring the expression of alkaline phosphatase (ALP using a commercial assay kit. Cell attachment was similar on all the oxidized surfaces although ALP expression was highest on the oxidized titanium alloy surfaces. Untreated titanium alloy surfaces showed a distinctly lower degree of ALP activity. This indicates that titanium oxide clearly upregulates ALP expression in human fetal osteoblasts and may be a key bioactive factor that causes the excellent biocompatibility of titanium alloys. This result may make it imperative to incorporate titanium oxide in all hard tissue applications involving titanium and other alloys.

  10. Redox Stable Anodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Guoliang eXiao

    2014-06-01

    Full Text Available Solid oxide fuel cells (SOFCs can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as the fuel. This review aims to highlight recent progresses on improving redox stability of the conventional Ni-based anode through microstructure optimization and exploration of alternative ceramic-based anode materials.

  11. Characteristics of titanium dioxide nanostructures synthesized via electrochemical anodization at different applied voltages

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Y. L.; Yam, F. K.; Hassan, Z. [Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-05-15

    This paper presents the study of the growth of nanostructure titanium dioxide (TiO{sub 2}) via electrochemical anodization method. Both constant and alternating anodization voltage would be applied in this study. The effects of applied voltage on the morphological and structural properties were studied. Images of field emission scanning electron microscope (FE-SEM) revealed that morphology of nanostructure could be manipulated by changing the type and amount of applied voltage. Besides that, X-ray diffraction (XRD) results indicated that crystalline structures (anatase and rutile) could be obtained after being annealed at 700°C for 60 minutes. By analysing the data in XRD measurements, crystallite size of the TiO{sub 2} could be calculated by using the Scherrer method. Besides that, the relationship between mean crystallites sizes and anodization voltage would also be further studied in this paper.

  12. The rapid growth of 3 µm long titania nanotubes by anodization of titanium in a neutral electrochemical bath

    Science.gov (United States)

    Lockman, Zainovia; Ismail, Syahriza; Sreekantan, Srimala; Schmidt-Mende, L.; MacManus-Driscoll, J. L.

    2010-02-01

    The length of titania nanotubes formed by anodization of 0.1 mm thick titanium foil was found to be a strong function of the pH of the electrolyte. The longest nanotubes were formed by using an electrolyte consisting of 1 M Na2SO4 plus 5 wt% NH4F with pH 7. At this pH, after 30 min of anodization, 3 µm length nanotubular titania arrays with top diameters of ~50 nm and bottom diameters of 100 nm were produced. No acid was added to this electrolyte. The formation of titania nanotubes in neutral pH systems was therefore successful due to the excess NH4F in the electrolyte which increases the chemical dissolution process at the metal/oxide interface. Since the pH of the electrolyte at the top part of the nanotubes is kept very high, the dissolution of the nanotubes at the surface is minimal. However, the amount is adequate to remove the initial barrier layer, forming a rather well-defined nanoporous structure. All anodized foils were weakly crystalline and the transformation to anatase phase was achieved by heat treatment at temperatures from 200 to 500 °C for 1 h in air. Annealing at temperatures above 500 °C induce rutile phase formation and annealing at higher temperatures accelerates the diffusion of Ti4+ leading to excessive growth and the nanotubular structure diminishes.

  13. The rapid growth of 3 {mu}m long titania nanotubes by anodization of titanium in a neutral electrochemical bath

    Energy Technology Data Exchange (ETDEWEB)

    Lockman, Zainovia; Ismail, Syahriza; Sreekantan, Srimala [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Schmidt-Mende, L [Munich Department of Physics and Centre for NanoScience (CeNS), Ludwig-Maximilians University, Amalienstrasse, 54, 80799 Munich (Germany); MacManus-Driscoll, J L, E-mail: zainovia@eng.usm.my [Department of Materials and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)

    2010-02-05

    The length of titania nanotubes formed by anodization of 0.1 mm thick titanium foil was found to be a strong function of the pH of the electrolyte. The longest nanotubes were formed by using an electrolyte consisting of 1 M Na{sub 2}SO{sub 4} plus 5 wt% NH{sub 4}F with pH 7. At this pH, after 30 min of anodization, 3 {mu}m length nanotubular titania arrays with top diameters of {approx}50 nm and bottom diameters of 100 nm were produced. No acid was added to this electrolyte. The formation of titania nanotubes in neutral pH systems was therefore successful due to the excess NH{sub 4}F in the electrolyte which increases the chemical dissolution process at the metal/oxide interface. Since the pH of the electrolyte at the top part of the nanotubes is kept very high, the dissolution of the nanotubes at the surface is minimal. However, the amount is adequate to remove the initial barrier layer, forming a rather well-defined nanoporous structure. All anodized foils were weakly crystalline and the transformation to anatase phase was achieved by heat treatment at temperatures from 200 to 500 deg. C for 1 h in air. Annealing at temperatures above 500 deg. C induce rutile phase formation and annealing at higher temperatures accelerates the diffusion of Ti{sup 4+} leading to excessive growth and the nanotubular structure diminishes.

  14. The rapid growth of 3 microm long titania nanotubes by anodization of titanium in a neutral electrochemical bath.

    Science.gov (United States)

    Lockman, Zainovia; Ismail, Syahriza; Sreekantan, Srimala; Schmidt-Mende, L; Macmanus-Driscoll, J L

    2010-02-05

    The length of titania nanotubes formed by anodization of 0.1 mm thick titanium foil was found to be a strong function of the pH of the electrolyte. The longest nanotubes were formed by using an electrolyte consisting of 1 M Na(2)SO(4) plus 5 wt% NH(4)F with pH 7. At this pH, after 30 min of anodization, 3 microm length nanotubular titania arrays with top diameters of approximately 50 nm and bottom diameters of 100 nm were produced. No acid was added to this electrolyte. The formation of titania nanotubes in neutral pH systems was therefore successful due to the excess NH(4)F in the electrolyte which increases the chemical dissolution process at the metal/oxide interface. Since the pH of the electrolyte at the top part of the nanotubes is kept very high, the dissolution of the nanotubes at the surface is minimal. However, the amount is adequate to remove the initial barrier layer, forming a rather well-defined nanoporous structure. All anodized foils were weakly crystalline and the transformation to anatase phase was achieved by heat treatment at temperatures from 200 to 500 degrees C for 1 h in air. Annealing at temperatures above 500 degrees C induce rutile phase formation and annealing at higher temperatures accelerates the diffusion of Ti(4+) leading to excessive growth and the nanotubular structure diminishes.

  15. Photoelectrochemical water splitting on chromium-doped titanium dioxide nanotube photoanodes prepared by single-step anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Momeni, Mohamad Mohsen, E-mail: mm.momeni@cc.iut.ac.ir; Ghayeb, Yousef

    2015-07-15

    Graphical abstract: Current–potential curves with chopped light measured in 1 M NaOH with a scan rate of 5 mV s{sup −1} for the different samples. - Highlights: • Cr-doped TiO{sub 2} nanotube layers (Cr–TiO{sub 2}NTs) were synthesized by anodizing of titanium in a single-step process. • Photoelectrochemical water splitting of Cr–TiO{sub 2}NTs is higher than that of pure TiO{sub 2} nanotubes (TiO{sub 2}NTs). • Quantity effect of chromium in these composite for photoelectrochemical water splitting is investigated. • Maximum hydrogen production of 37 μL/cm{sup 2} after 240 min is obtained. - Abstract: Cr-doped TiO{sub 2} nanotubes (Cr–TiO{sub 2}NTs) with different amounts of chromium were obtained directly by the electrochemical anodic oxidation of titanium foils in a single-step process using potassium chromate as the chromium source. The effects of chromium amount in anodizing solution on the morphologies, structure, photoabsorption and photoelectrochemical water splitting of the TiO{sub 2} nanotube array film were investigated. Diffuse reflectance spectra showed an increase in the visible absorption relative to undoped TiO{sub 2}NTs. The photoelectrochemical performance was examined under visible irradiation in 1 M NaOH electrolyte. Photo-electrochemical characterization shows that chromium doping efficiently enhances the photo-catalytic water splitting performance of Cr-doped TiO{sub 2} nanotube samples. The sample (Cr–TiO{sub 2}NTs-1) exhibited better photo-catalytic activity than the undoped TiO{sub 2}NTs and Cr–TiO{sub 2}NTs fabricated using other chromium concentrations. This can be attributed to the effective separation of photogenerated electron–hole upon the substitutional introduction of appropriate Cr amount in to the TiO{sub 2} nanotube structure.

  16. Semi-transparent ordered TiO2 nanostructures prepared by anodization of titanium thin films deposited onto the FTO substrate

    Science.gov (United States)

    Szkoda, Mariusz; Lisowska-Oleksiak, Anna; Grochowska, Katarzyna; Skowroński, Łukasz; Karczewski, Jakub; Siuzdak, Katarzyna

    2016-09-01

    In a significant amount of cases, the highly ordered TiO2 nanotube arrays grow through anodic oxidation of a titanium metal plate immersed in electrolyte containing fluoride ions. However, for some practical applications, e.g. solar cells or electrochromic windows, the semi-transparent TiO2 formed directly on the transparent, conductive substrate is very much desired. This work shows that high-quality Ti coating could be formed at room temperature using an industrial magnetron sputtering system within 50 min. Under optimized conditions, the anodization process was performed on 2 μm titanium films deposited onto the FTO (fluorine-tin-oxide) support. Depending on the electrolyte type, highly ordered tubular or porous titania layers were obtained. The fabricated samples, after their thermal annealing, were investigated using scanning electron microscopy, Raman spectroscopy and UV-vis spectroscopy in order to investigate their morphology, crystallinity and absorbance ability. The photocurrent response curves indicate that materials are resistant to the photocorrosion process and their activity is strongly connected to optical properties. The most transparent TiO2 films were fabricated when Ti was anodized in water electrolyte, whereas the highest photocurrent densities (12 μA cm-2) were registered for titania received after Ti anodization in ethylene glycol solution. The obtained results are of significant importance in the production of thin, semi-transparent titania nanostructures on a commercial scale.

  17. Micro- and nanomorphology coexisting in titanium dioxide coating for application as anode material in secondary lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Wen-Chi, E-mail: wenchilo694@gmail.com; Chu, Hou-Jen; He, Ju-Liang

    2015-03-31

    Titanium dioxide has recently attracted attention as an anode material for use in lithium-ion batteries, owing to its high reversible capacity and durable charge/discharge characteristics. The aim of the study is to combine micro-arc oxidation (MAO) and post-alkali treatment to realize an anatase titanium dioxide (TiO{sub 2}) scaffold layer on titanium plates. Using this combination, coexisting micro- and nanomorphology can be realized in the TiO{sub 2} layer. This increases the specific surface area of the TiO{sub 2} layer and thereby improves the charge capacity and charge/discharge rate of the anode. The effectiveness of MAO to fabricate a micrometer-scale porous TiO{sub 2} structure on titanium plate, and the formation of nano-flakes by alkali treatment on porous anatase TiO{sub 2} layer was demonstrated. Further, numerous 40–80 nm alkali-treatment-induced nano-flakes grew all over the oxide surface, substantially increasing its specific surface area. The measured electrochemical properties demonstrate that at potentials of − 1.98 V and − 0.56 V vs. Ag/AgCl, lithium ions were respectively inserted into and extracted from the TiO{sub 2} layer with nano-flakes. The nano-flakes promote faster lithium-ion insertion and extraction and higher associated number of charge than the MAO TiO{sub 2}. The detailed charging/discharging kinetic processes of the MAO, annealed MAO, alkali-treated MAO, and annealed and alkali-treated MAO specimens were determined using electrochemical impedance spectroscopy, thus providing further insight into the performance of the TiO{sub 2} coating. - Highlights: • A micrometer-scale porous crystalline TiO{sub 2} layer was fabricated by MAO. • After alkali treatment, the oxide surface exhibits numerous pores. • The layer was composed of predominantly anatase and minor rutile. • Optimum solution temperature and NaOH concentration yielded nano-flaky morphology. • Such morphology leads to the increase performance of the treated

  18. Semi-transparent ordered TiO{sub 2} nanostructures prepared by anodization of titanium thin films deposited onto the FTO substrate

    Energy Technology Data Exchange (ETDEWEB)

    Szkoda, Mariusz, E-mail: mariusz-szkoda@wp.pl [Department of Chemistry and Technology of Functional Materials, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, Gdańsk 80-233 (Poland); Lisowska-Oleksiak, Anna [Department of Chemistry and Technology of Functional Materials, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, Gdańsk 80-233 (Poland); Grochowska, Katarzyna [Centre for Plasma and Laser Engineering, Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Science, Fiszera 14, 80-231 Gdańsk (Poland); Skowroński, Łukasz [Institute of Mathematics and Physics, UTP University of Science and Technology, Kaliskiego 7, 85-796 Bydgoszcz (Poland); Karczewski, Jakub [Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk (Poland); Siuzdak, Katarzyna [Centre for Plasma and Laser Engineering, Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Science, Fiszera 14, 80-231 Gdańsk (Poland)

    2016-09-15

    Highlights: • High quality titanium coatings were doposited using industrial magnetron sputtering equipment. • Semi-transparent TiO{sub 2} were prepared via anodization realized in various conditions. • Depending on electrolyte type, ordered tubular or porous TiO{sub 2} layers were obtained. • Prepared material can act as semiconducting layer in photovoltaic cells. - Abstract: In a significant amount of cases, the highly ordered TiO{sub 2} nanotube arrays grow through anodic oxidation of a titanium metal plate immersed in electrolyte containing fluoride ions. However, for some practical applications, e.g. solar cells or electrochromic windows, the semi-transparent TiO{sub 2} formed directly on the transparent, conductive substrate is very much desired. This work shows that high-quality Ti coating could be formed at room temperature using an industrial magnetron sputtering system within 50 min. Under optimized conditions, the anodization process was performed on 2 μm titanium films deposited onto the FTO (fluorine-tin-oxide) support. Depending on the electrolyte type, highly ordered tubular or porous titania layers were obtained. The fabricated samples, after their thermal annealing, were investigated using scanning electron microscopy, Raman spectroscopy and UV–vis spectroscopy in order to investigate their morphology, crystallinity and absorbance ability. The photocurrent response curves indicate that materials are resistant to the photocorrosion process and their activity is strongly connected to optical properties. The most transparent TiO{sub 2} films were fabricated when Ti was anodized in water electrolyte, whereas the highest photocurrent densities (12 μA cm{sup −2}) were registered for titania received after Ti anodization in ethylene glycol solution. The obtained results are of significant importance in the production of thin, semi-transparent titania nanostructures on a commercial scale.

  19. Anodic aluminium oxide catalytic membranes for asymmetric epoxidation.

    Science.gov (United States)

    Cho, So-Hye; Walther, Nolan D; Nguyen, SonBinh T; Hupp, Joseph T

    2005-11-14

    Catechol-functionalized (salen)Mn complexes can be supported on mesoporous anodized aluminium oxide disks to yield catalytic membranes that are highly active in the enantioselective epoxidation of olefins when being deployed in a forced-through-flow reactor.

  20. Self-ordering behavior of nanoporous anodic aluminum oxide (AAO) in malonic acid anodization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W; Nielsch, K; Goesele, U [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany)

    2007-11-28

    The self-ordering behavior of anodic aluminum oxide (AAO) has been investigated for anodization of aluminum in malonic acid (H{sub 4}C{sub 3}O{sub 4}) solution. In the present study it is found that a porous oxide layer formed on the surface of aluminum can effectively suppress catastrophic local events (such as breakdown of the oxide film and plastic deformation of the aluminum substrate), and enables stable fast anodic oxidation under a high electric field of 110-140 V and {approx}100 mA cm{sup -2}. Studies on the self-ordering behavior of AAO indicated that the cell homogeneity of AAO increases dramatically as the anodization voltage gets higher than 120 V. Highly ordered AAO with a hexagonal arrangement of the nanopores could be obtained in a voltage range 125-140 V. The current density (i.e., the electric field strength (E) at the bottom of a pore) is an important parameter governing the self-ordering of the nanopores as well as the interpore distance (D{sub int}) for a given anodization potential (U) during malonic acid anodization.

  1. Effects of Oxide Film on the Corrosion Resistance of Titanium Grade 7 in Fluoride-Containing NaCl Brines

    Energy Technology Data Exchange (ETDEWEB)

    Lian, T; Whalen, M T; Wong, L

    2004-11-30

    The effects of oxide film on the corrosion behavior of Titanium Grade 7 (0.12-0.25% Pd) in fluoride-containing NaCl brines have been investigated. With the presence of a 0.6 {micro}m thick oxide layer, the annealed Ti grade 7 exhibited a significant improvement on the anodic polarization behavior. However, the oxide film did not demonstrate sustainable corrosion resistance in fluoride-containing solutions.

  2. Electrochemical oxidation of reverse osmosis concentrate on mixed metal oxide (MMO) titanium coated electrodes.

    Science.gov (United States)

    Bagastyo, Arseto Y; Radjenovic, Jelena; Mu, Yang; Rozendal, René A; Batstone, Damien J; Rabaey, Korneel

    2011-10-15

    Reverse osmosis (RO) membranes have been successfully applied around the world for wastewater reuse applications. However, RO is a physical separation process, and besides the clean water stream (permeate) a reverse osmosis concentrate (ROC) is produced, usually representing 15-25% of the feed water flow and containing the organic and inorganic contaminants at higher concentrations. In this study, electrochemical oxidation was investigated for the treatment of ROC generated during the reclamation of municipal wastewater effluent. Using laboratory-scale two-compartment electrochemical systems, five electrode materials (i.e. titanium coated with IrO2-Ta2O5, RuO2-IrO2, Pt-IrO2, PbO2, and SnO2-Sb) were tested as anodes in batch mode experiments, using ROC from an advanced water treatment plant. The best oxidation performance was observed for Ti/Pt-IrO2 anodes, followed by the Ti/SnO2-Sb and Ti/PbO2 anodes. The effectiveness of the treatment appears to correlate with the formation of oxidants such as active chlorine (i.e. Cl2/HClO/ClO-). As a result, electro-generated chlorine led to the abundant formation of harmful by-products such as trihalomethanes (THMs) and haloacetic acids (HAAs), particularly at Ti/SnO2-Sb and Ti/Pt-IrO2 anodes. The highest concentration of total HAAs (i.e. 2.7 mg L(-1)) was measured for the Ti/SnO2-Sb electrode, after 0.55 Ah L(-1) of supplied specific electrical charge. Irrespective of the used material, electrochemical oxidation of ROC needs to be complemented by a polishing treatment to alleviate the release of halogenated by-products. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Synergism between anodic oxidation with diamond anodes and heterogeneous catalytic photolysis for the treatment of pharmaceutical pollutants

    Directory of Open Access Journals (Sweden)

    Juan M. Peralta-Hernández

    2016-03-01

    Full Text Available The mineralization of diclofenac and acetaminophen has been studied by single anodic oxidation with boron-doped diamond (AO-BDD using an undivided electrolysis cell, by single heterogeneous catalytic photolysis with titanium dioxide (HCP-TiO2 and by the combination of both advanced oxidation processes. The results show that mineralization can be obtained with either single technology. The type of functional groups of the pollutant does not influence the results of the single AO-BDD process, but it has a significant influence on the results obtained with HCP-TiO2. A clear synergistic effect appears when both processes are combined showing improvements in the oxidation rate of more than 50% for diclofenac and nearly 200% for acetaminophen at the highest current exerted. Results obtained are explained in terms of the production of oxidants on the surface of BDD (primarily peroxodisulfate and the later homogeneous catalytic light decomposition of these oxidants in the bulk. This mechanism is consistent with the larger improvement observed at higher current densities, for which the production of oxidants is promoted.

  4. Selection of crucible oxides in molten titanium and titanium aluminum alloys by thermo-chemistry calculations

    Directory of Open Access Journals (Sweden)

    Kostov A.

    2005-01-01

    Full Text Available Titanium and its alloys interstitially dissolve a large amount of impurities such as oxygen and nitrogen, which degrade the mechanical and physical properties of alloys. On the other hand crucible oxides based on CaO, ZrO2 Y2O3, etc., and their spinels (combination of two or more oxides can be used for melting titanium and its alloys. However, the thermodynamic behavior of calcium, zirconium, yttrium on the one side, and oxygen on the other side, in molten Ti and Ti-Al alloys have not been made clear and because of that, it is very interesting for research. Owing of literature data, as well as these crucibles are cheaper than standard crucibles for melting titanium and titanium alloys, in this paper will be presented the results of selection of thermo-chemistry analysis with the aim to determine the crucible oxide stability in contact with molten titanium and titanium-aluminum alloys.

  5. Effect of processing on structural features of anodic aluminum oxides

    Science.gov (United States)

    Erdogan, Pembe; Birol, Yucel

    2012-09-01

    Morphological features of the anodic aluminum oxide (AAO) templates fabricated by electrochemical oxidation under different processing conditions were investigated. The selection of the polishing parameters does not appear to be critical as long as the aluminum substrate is polished adequately prior to the anodization process. AAO layers with a highly ordered pore distribution are obtained after anodizing in 0.6 M oxalic acid at 20 °C under 40 V for 5 minutes suggesting that the desired pore features are attained once an oxide layer develops on the surface. While the pore features are not affected much, the thickness of the AAO template increases with increasing anodization treatment time. Pore features are better and the AAO growth rate is higher at 20 °C than at 5 °C; higher under 45 V than under 40 V; higher with 0.6 M than with 0.3 M oxalic acid.

  6. The formation of micrometer-long TiO2 nanotube arrays by anodization of titanium film on conducting glass substrate

    Science.gov (United States)

    Tang, Yuxin; Tao, Jie; Dong, Zhili; Tien Oh, Joo; Chen, Zhong

    2011-12-01

    Micrometer-long titanium oxide nanotube arrays, tens of nanometers in diameter, were fabricated by anodization of titanium film coated on a conducting glass substrate. The Ti film was deposited by magnetron sputtering at room temperature. The effect of anodizing conditions on the formation of TiO2 nanotubes was investigated. The results indicate that dense and uniform Ti film deposited under 150 W at room temperature was favorable for the formation of ordered nanotube arrays. The average diameter of the TiO2 nanotubes varied from 35 to 95 nm when the anodization potential changed from 10 to 40 V. Micrometer-long nanotubes (1.1 μm) with good adhesion to the substrate could be obtained in 0.5 wt% NH4F/glycerol at 30 V for 2 h. After heat treatment, the crystalline anatase nanotubes show enhanced photoelectrochemical activity compared with those anodized in 1 M H3PO4/0.5 wt% HF. This is attributed to the increased light-harvesting abilities.

  7. In vitro biocompatibility of titanium-nickel alloy with titanium oxide film by H2O2 oxidation

    Institute of Scientific and Technical Information of China (English)

    HU Tao; CHU Cheng-lin; YIN Li-hong; PU Yao-pu; DONG Yin-sheng; GUO Chao; SHENG Xiao-bo; CHUNG Jonathan-CY; CHU Paul-K

    2007-01-01

    Titanium oxide film with a graded interface to NiTi matrix was synthesized in situ on NiTi shape memory alloy(SMA) by oxidation in H2O2 solution. In vitro studies including contact angle measurement, hemolysis, MTT cytotoxicity and cell morphology tests were employed to investigate the biocompatibility of the H2O2-oxidized NiTi SMAs with this titanium oxide film. The results reveal that wettability, blood compatibility and fibroblasts compatibility of NiTi SMA are improved by the coating of titanium oxide film through H2O2 oxidation treatment.

  8. Surface integrity after pickling and anodization of Ti–6Al–4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Vermesse, Eric [Institut Clément Ader (ICA), Université de Toulouse, ISAE, Toulouse (France); Université de Toulouse, Institut Carnot CIRIMAT, UMR CNRS-UPS-INP 5085, Université Paul Sabatier, 118, route de Narbonne, 31062 Toulouse cedex 9 (France); Mabru, Catherine [Institut Clément Ader (ICA), Université de Toulouse, ISAE, Toulouse (France); Arurault, Laurent, E-mail: arurault@chimie.ups-tlse.fr [Université de Toulouse, Institut Carnot CIRIMAT, UMR CNRS-UPS-INP 5085, Université Paul Sabatier, 118, route de Narbonne, 31062 Toulouse cedex 9 (France)

    2013-11-15

    The surface integrity of Ti–6Al–4V titanium alloy was studied at different stages of surface treatments, especially pickling and compact anodization, through surface characteristics potentially worsening fatigue resistance. No significant changes of the equiaxe microstructure were detected between sample core and surface, or after the pickling and anodization steps. Surface hydrogen and oxygen superficial contents were found to remain unchanged. Roughness characteristics (i.e. R{sub a}, R{sub z} but also local K{sub t} factor) similarly showed only slight modifications, although SPM and SEM revealed certain random local surface defaults, i.e. pits about 400 nm in depth. Finally internal stresses, evaluated using X-ray diffraction, highlighted a significant decrease of the compressive internal stresses, potentially detrimental for fatigue resistance.

  9. Self-Ordered Titanium Dioxide Nanotube Arrays: Anodic Synthesis and Their Photo/Electro-Catalytic Applications

    Science.gov (United States)

    Smith, York R.; Ray, Rupashree S.; Carlson, Krista; Sarma, Biplab; Misra, Mano

    2013-01-01

    Metal oxide nanotubes have become a widely investigated material, more specifically, self-organized titania nanotube arrays synthesized by electrochemical anodization. As a highly investigated material with a wide gamut of applications, the majority of published literature focuses on the solar-based applications of this material. The scope of this review summarizes some of the recent advances made using metal oxide nanotube arrays formed via anodization in solar-based applications. A general methodology for theoretical modeling of titania surfaces in solar applications is also presented. PMID:28811415

  10. Role of aluminum doping on phase transformations in nanoporous titania anodic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bayata, Fatma [Istanbul Bilgi University, Department of Mechanical Engineering, 34060, Eyup, Istanbul (Turkey); Ürgen, Mustafa, E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469, Maslak, Istanbul (Turkey)

    2015-10-15

    The role of aluminium doping on anatase to rutile phase transformation of nanoporous titanium oxide films were investigated. For this purpose pure and aluminum doped metal films were deposited on alumina substrates by cathodic arc physical deposition. The nanoporous anodic oxides were prepared by porous anodizing of pure and aluminum doped titanium metallic films in an ethylene glycol + NH{sub 4}F based electrolyte. Nanoporous amorphous structures with 60–80 nm diameter and 2–4 μm length were formed on the surfaces of alumina substrates. The amorphous undoped and Al-doped TiO{sub 2} anodic oxides were heat-treated at different temperatures in the range of 280–720 °C for the investigation of their crystallization behavior. The combined effects of nanoporous structure and Al doping on crystallization behavior of titania were investigated using X-ray diffraction (XRD) and micro Raman analysis. The results indicated that both Al ions incorporated into the TiO{sub 2} structure and the nanoporous structure retarded the rutile formation. It was also revealed that presence or absence of metallic film underneath the nanopores has a major contribution to anatase-rutile transformation. - Highlights: • Al-doped TiO{sub 2} nanopores were grown on alumina substrates using anodization method. • The crystallization behavior of nanoporous Al-doped TiO{sub 2} were investigated. • Al doping into nanoporous TiO{sub 2} retarded the anatase-rutile transformation. • Nanostructuring has significant role in controlling rutile formation temperature. • The absence of the metallic film under the nanopores delayed the rutile formation.

  11. Tunable structural color of anodic tantalum oxide films

    Institute of Scientific and Technical Information of China (English)

    Sheng Cui-Cui; Cai Yun-Yu; Dai En-Mei; Liang Chang-Hao

    2012-01-01

    Tantalum (Ta) oxide films with tunable structural color were fabricated easily using anodic oxidation.The structure,components,and surface valence states of the oxide filns were investigated by using gazing incidence X-ray diffractometry,X-ray photoelectron microscopy,and surface analytical techniques.Their thickness and optical properties were studied by using spectroscopic ellipsometry and total reflectance spectrum.Color was accurately defined using L*a*b* scale.The thickness of compact Ta2O5 films was linearly dependent on anodizing voltage.The film color was tunable by adjusting the anodic voltage.The difference in color appearance resulted from the interference behavior between the interfaces of air-oxide and oxide-metal.

  12. 40 CFR 721.10021 - Magnesium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium...

  13. Fabrication of anodic aluminium oxide templates on curved surfaces.

    Science.gov (United States)

    Yin, Aijun; Guico, Rodney S; Xu, Jimmy

    2007-01-24

    Aluminium anodization provides a simple and inexpensive way to obtain nanoporous templates with uniform and controllable pore diameters and periods over a wide range. Moreover, one of the interesting possibilities afforded by the anodization process is that the anodization can take place on arbitrary surfaces, such as curved surfaces, which has not yet been well studied or applied in nanofabrication. In this paper, we characterize the anodization of Al films on silicon substrates with a curved top surface. The structures of the resultant anodic aluminium oxide (AAO) films are examined by scanning electron microscopy. Unique features including cessation, bending, and branching of pore channels are observed in the curved area. Possible growth mechanisms are proposed, which can also contribute to the understanding of the self-organization mechanism in the formation of porous AAO membranes. The new structures may open new opportunities in optical, electronic and electrochemical applications.

  14. Fabrication of anode supported PEN for solid oxide fuel cell

    Institute of Scientific and Technical Information of China (English)

    谢淑红; 崔崑; 夏风; 肖建中

    2004-01-01

    Fabrication process for anode supported planar PEN of intermediate temperature solid oxide fuel cell (SOFC) was introduced, in which tape casting and screen printing methods were used. Gd2O3 doped CeO2(GDC) powders were prepared by solid reaction method. Anode tape was produced by tape casting. Electrolyte and cathode were produced by screen printing. The GDC powder's component, thermal expand coefficient, the porosity, density and microstructure of anode and electrolyte were investigated . It was shown that an bi-layer with dense thin electrolyte film and porous anode support and with good coherency of the electrolyte film to the anode could be realized after co-sintering the green tape at 1 350℃ by optimizing the power characteristics of the starting materials in the slurry.

  15. Fabrication of Novel Titanium-supported Ni-Sn Catalysts for Methanol Electro-oxidation

    Institute of Scientific and Technical Information of China (English)

    YI Qing-Feng; HUANG Wu; YU Wen-Qiang; LI Lei; LIU Xiao-Ping

    2008-01-01

    Novel titanium-supported Ni-Sn/Ti electrodes (Ni8Sn/Ti, Ni7Sn3/Ti and Ni/Ti) have been prepared using a hydrothermal method by a one step process. The scanning electron microscopy (SEM) images show that the catalyst particles are present as nano-scale flakes. Their electrochemical activity for methanol oxidation in 1 mol·L-1 NaOH was evaluated using voltammetric techniques, chronoamperometric measurements and electrochemical impedance spectra (EIS). It was found that the Ni8Sn/Ti electrode presents higher anodic currents and lower onset potential for methanol oxidation than Ni7Sn3/Ti, Ni/Ti and polycrystalline Ni electrodes. The EIS data indicate that under condi- tions of various anodic potentials and methanol concentrations, the Ni8Sn/Ti electrode displays significantly lower charge transfer resistances and high electrocatalytic activity towards methanol oxidation.

  16. Formation of anodic aluminum oxide with serrated nanochannels.

    Science.gov (United States)

    Li, Dongdong; Zhao, Liang; Jiang, Chuanhai; Lu, Jia G

    2010-08-11

    We report a simple and robust method to self-assemble porous anodic aluminum oxide membranes with serrated nanochannels by anodizing in phosphoric acid solution. Due to high field conduction and anionic incorporation, an increase of anodizing voltage leads to an increase of the impurity levels and also the field strength across barrier layer. On the basis of both experiment and simulation results, the initiation and formation of serrated channels are attributed to the evolution of oxygen gas bubbles followed by plastic deformation in the oxide film. Alternating anodization in oxalic and phosphoric acids is applied to construct multilayered membranes with smooth and serrated channels, demonstrating a unique way to design and construct a three-dimensional hierarchical system with controllable morphology and composition.

  17. Effect of surface treatments on anodic oxide film growth and electrochemical properties of tantalum used for biomedical applications.

    Science.gov (United States)

    Silva, R A; Silva, I P; Rondot, B

    2006-07-01

    Self-expandable nitinol (nickel-titanium) alloys and 316L stainless steel are the most commonly used materials in the production of coronary stents. However, tantalum (Ta) has already been used to make stents for endovascular surgery and may constitute an alternative to other materials because of its better electrochemical performance, namely its higher corrosion resistance, as well as its radio-opacity. The characterization of wet polished, chemically polished, wet polished anodized, and chemically polished anodized Ta electrodes has been performed in a 0.15 M NaCl solution (simulated body fluid) using Ucorr = f(t) measurements, anodic polarizations, capacity measurements, anodic oxidations, and atomic force microscopy (AFM) imaging. Anodic polarization curves have shown that the abnormal current density peak with a maximum value around 1.65 V (critical applied potential, Uc) disappeared for the anodized electrodes indicating a probable relationship between the surface states and the film growth. These results are confirmed by capacity measurements. The behavior of wet polished and chemically polished electrodes during anodic oxidations seemingly indicated that for these particular treatments the film growth is different. The AFM images and roughness measurements have shown that chemical polishing produced smoother electrodes, a fact probably related to the differences in film growth.

  18. ELLIPSOMETRIC INVESTIGATION OF THE SILICON / ANODIC-OXIDE INTERFACE

    OpenAIRE

    Palik, E.; Bermudez, V.

    1983-01-01

    Ellipsometric measurements have been carried out during growth and etch back of anodic oxides on Si in 2M KOH. Pronounced variations in ψ and Ɗ occur as etching proceeds through the SiO2/Si interface and also during the initial stages of re-anodization. The results are interpreted in terms of changes in the stoichiometry and thickness of an SiOx (0⩽x⩽2) connective layer.

  19. Sol-gel prepared active ternary oxide coating on titanium in cathodic protection

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2007-12-01

    Full Text Available The characteristics of a ternary oxide coating, on titanium, which consisted of TiO2, RuO2 and IrO2 in the molar ratio 0.6:0.3:0.1, calculated on the metal atom, were investigated for potential application for cathodic protection in a seawater environment. The oxide coatings on titanium were prepared by the sol gel procedure from a mixture of inorganic oxide sols, which were obtained by forced hydrolysis of metal chlorides. The morphology of the coating was examined by scanning electron microscopy. The electrochemical properties of activated titanium anodes were investigated by cyclic voltammetry and polarization measurements in a H2SO4- and NaCl-containing electrolyte, as well as in seawater sampled on the Adriatic coast in Tivat, Montenegro. The anode stability during operation in seawater was investigated by the galvanostatic accelerated corrosion stability test. The morphology and electrochemical characteristics of the ternary coating are compared to that of a sol-gel-prepared binary Ti0.6Ru0.4O2 coating. The activity of the ternary coating was similar to that of the binary Ti0.6Ru0.4O2 coating in the investigated solutions. However, the corrosion stability in seawater is found to be considerably greater for the ternary coating.

  20. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  1. Corrosion of titanium in supercritical water oxidation environments

    Institute of Scientific and Technical Information of China (English)

    卢建树; 毛志远; 张九渊; 马淳安; 毛信表; 李肖华

    2002-01-01

    Supercritical water oxidation (SCWO) can effectively destroy many kinds of civilian and military wastes. The high temperature and high pressure SCWO operation conditions generate very corrosive environment that many engineering materials fail to withstand. Preliminary test shows that titanium may be a promising material in most of SCWO conditions. Commercially pure titanium is tested in four kinds of SCWO environments. Phenol, sodium dodecyl-benzosulfonate, n-amine phenol, and chlorpyrifos were chosen as typical target pollutants. The results show that titanium is only superficially attacked in the first three SCWO environments while in chlorpyrifos SCWO medium titanium is corroded. The corrosion is temperature dependent, with heavier corrosion occurring at near critical temperature. X-ray diffraction analysis shows that the corrosion products consist of titanium oxy- phosphates and titanium oxide, in which Ti5O4(PO4)4 is the main phase.

  2. Photo-electrochemical hydrogen generation using band-gap modified nanotubular titanium oxide in solar light

    Science.gov (United States)

    Raja, K. S.; Misra, M.; Mahajan, V. K.; Gandhi, T.; Pillai, P.; Mohapatra, S. K.

    Anodization of Ti in acidified fluoride solution results in an ordered nanotubular titanium oxide surface. In this study, vertically oriented arrays of TiO 2 nanotubes were prepared by incorporating nitrate and phosphate species during the anodization process. These nanotubes were annealed at 650 °C in a carbonaceous atmosphere using a chemical vapor deposition (CVD) furnace for a brief period. The carbon-modified nanotubular TiO 2 produced a photo-current density of more than 2.75 mA cm -2 at 0.2 V Ag/AgCl under solar light illumination. This photo-current density corresponds to a hydrogen evolution rate of about 11 l h -1 using a photo-anode of 1 m 2 area. The enhanced hydrogen evolution behavior of carbon-modified nanotubular TiO 2 is highly reproducible and sustainable for long duration. Annealed (at 350 °C in nitrogen atmosphere) TiO 2 nanotubes showed improved photo-activity as compared to the as-anodized or thermally oxidized TiO 2 photo-anodes.

  3. Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

    Directory of Open Access Journals (Sweden)

    Gerrard Eddy Jai Poinern

    2011-02-01

    Full Text Available The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

  4. Greater osteoblast functions on multiwalled carbon nanotubes grown from anodized nanotubular titanium for orthopedic applications

    Science.gov (United States)

    Sirivisoot, Sirinrath; Yao, Chang; Xiao, Xingcheng; Sheldon, Brian W.; Webster, Thomas J.

    2007-09-01

    Titanium (Ti) is the most widely implanted orthopedic material. However, current formulations of Ti have an average orthopedic implant functional lifetime of only 10-15 years. While there are many reasons why orthopedic implants fail, one is a lack of initial and sustained integration into juxtaposed bone. To improve the cytocompatibility properties of Ti for orthopedic applications, parallel multiwalled carbon nanotubes (CNTs) were grown from the pores of anodized nanotubular Ti by a chemical vapor deposition process in the present study. The results of this study provided evidence, for the first time, that osteoblast (bone forming cell) functions (specifically, alkaline phosphatase activity and calcium deposition) were significantly greater on CNTs grown from anodized Ti than on anodized Ti without CNTs and currently-used Ti in orthopedics for up to 21 days. In summary, this study showed that bone growth could possibly be enhanced on currently-used Ti implants with protruding CNTs and, thus, they should be further studied for orthopedic applications.

  5. Impact of anode microstructure on solid oxide fuel cells.

    Science.gov (United States)

    Suzuki, Toshio; Hasan, Zahir; Funahashi, Yoshihiro; Yamaguchi, Toshiaki; Fujishiro, Yoshinobu; Awano, Masanobu

    2009-08-14

    We report a correlation between the microstructure of the anode electrode of a solid oxide fuel cell (SOFC) and its electrochemical performance for a tubular design. It was shown that the electrochemical performance of the cell was extensively improved when the size of constituent particles was reduced so as to yield a highly porous microstructure. The SOFC had a power density of greater than 1 watt per square centimeter at an operating temperature as low as 600 degrees C with a conventional zirconia-based electrolyte, a nickel cermet anode, and a lanthanum ferrite perovskite cathode material. The effect of the hydrogen fuel flow rate (linear velocity) was also examined for the optimization of operating conditions. Higher linear fuel velocity led to better cell performance for the cell with higher anode porosity. A zirconia-based cell could be used for a low-temperature SOFC system under 600 degrees C just by optimizing the microstructure of the anode electrode and operating conditions.

  6. Anodic oxidation of stilbenes bearing electron-withdrawing ring substituents

    Energy Technology Data Exchange (ETDEWEB)

    Halas, Summer M.; Okyne, Kwame; Fry, Albert J

    2003-06-15

    A number of disubstituted stilbenes bearing either two strong electron-withdrawing groups or one electron-withdrawing and one electron-donating group were synthesized and anodically oxidized in a divided cell in methanol at a carbon anode. A variety of types of products were obtained, most of which have never been observed upon oxidation of alkenes not bearing electron-withdrawing groups. A mechanistic scheme involving 2-methoxy-1,2-diarylethyl cations as key intermediates can account for all of the observed products. The nature of the products from each alkene is strongly correlated with the sum of the Hammett {sigma}{sup +} values of the ring substituents.

  7. Anodic oxidation with doped diamond electrodes: a new advanced oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, Alexander; Stadelmann, Manuela; Blaschke, Manfred

    2003-10-31

    Boron-doped diamond anodes allow to directly produce OH{center_dot} radicals from water electrolysis with very high current efficiencies. This has been explained by the very high overvoltage for oxygen production and many other anodic electrode processes on diamond anodes. Additionally, the boron-doped diamond electrodes exhibit a high mechanical and chemical stability. Anodic oxidation with diamond anodes is a new advanced oxidation process (AOP) with many advantages compared to other known chemical and photochemical AOPs. The present work reports on the use of diamond anodes for the chemical oxygen demand (COD) removal from several industrial wastewaters and from two synthetic wastewaters with malic acid and ethylenediaminetetraacetic (EDTA) acid. Current efficiencies for the COD removal between 85 and 100% have been found. The formation and subsequent removal of by-products of the COD oxidation has been investigated for the first time. Economical considerations of this new AOP are included.

  8. A Novel Investigation of the Formation of Titanium Oxide Nanotubes on Thermally Formed Oxide of Ti-6Al-4V.

    Science.gov (United States)

    Butt, Arman; Hamlekhan, Azhang; Patel, Sweetu; Royhman, Dmitry; Sukotjo, Cortino; Mathew, Mathew T; Shokuhfar, Tolou; Takoudis, Christos

    2015-10-01

    Traditionally, titanium oxide (TiO2) nanotubes (TNTs) are anodized on Ti-6Al-4V alloy (Ti-V) surfaces with native TiO2 (amorphous TiO2); subsequent heat treatment of anodized surfaces has been observed to enhance cellular response. As-is bulk Ti-V, however, is often subjected to heat treatment, such as thermal oxidation (TO), to improve its mechanical properties. Thermal oxidation treatment of Ti-V at temperatures greater than 200°C and 400°C initiates the formation of anatase and rutile TiO2, respectively, which can affect TNT formation. This study aims at understanding the TNT formation mechanism on Ti-V surfaces with TO-formed TiO2 compared with that on as-is Ti-V surfaces with native oxide. Thermal oxidation-formed TiO2 can affect TNT formation and surface wettability because TO-formed TiO2 is expected to be part of the TNT structure. Surface characterization was carried out with field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, water contact angle measurements, and white light interferometry. The TNTs were formed on control and 300°C and 600°C TO-treated Ti-V samples, and significant differences in TNT lengths and surface morphology were observed. No difference in elemental composition was found. Thermal oxidation and TO/anodization treatments produced hydrophilic surfaces, while hydrophobic behavior was observed over time (aging) for all samples. Reduced hydrophobic behavior was observed for TO/anodized samples when compared with control, control/anodized, and TO-treated samples. A method for improved surface wettability and TNT morphology is therefore discussed for possible applications in effective osseointegration of dental and orthopedic implants.

  9. Anodic oxide growth on Zr in neutral aqueous solution

    Indian Academy of Sciences (India)

    Z Tun; J J Noël; D W Shoesmith

    2008-10-01

    Anodization and subsequent cathodic reactions on a thin-film sample of Zr were studied with in-situ neutron reflectometry (NR) and electrochemical impedance spectroscopy (EIS). The NR results during anodization showed the originally 485 Å thick Zr film generally behaved similar to a bulk electrode in neutral solution. The anodization ratio measured at applied potentials increased in steps of 0.5 V was somewhat higher than the value determined by coulometry, while the Pilling Bedworth ratio is in good agreement with published data. Thickening of the oxide layer, accelerated immediately after each potential increase, gradually decreased over several hours, but remained non-zero even after ∼ 12 h. The thickened oxide eventually cracked when its thickness reached ∼ 120 Å, causing loss of passivation. Surprisingly, neither the anodization ratio nor the Pilling Bedworth ratio showed any discontinuity at the time of oxide cracking, and the EIS behaviour remained qualitatively as before. This observation is taken as the evidence that the cracked and intact regions of the electrode behave more or less independently as parallel electrodes. When the potential was eventually switched to cathodic polarity, NR shows, as expected, that the effects of oxide cracking were irreversible. However, the electrode resistance recovered partially suggesting the cracks were rapidly plugged with newly formed oxide.

  10. Anodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain

    An important issue that has limited the potential of Solid Oxide Fuel Cells (SOFCs) for portable applications is its high operating temperatures (800-1000 ºC). Lowering the operating temperature of SOFCs to 400-600 ºC enable a wider material selection, reduced degradation and increased lifetime....... On the other hand, low-temperature operation poses serious challenges to the electrode performance. Effective catalysts, redox stable electrodes with improved microstructures are the prime requisite for the development of efficient SOFC anodes. The performance of Nb-doped SrT iO3 (STN) ceramic anodes...... at 400ºC. The potential of using WO3 ceramic as an alternative anode materials has been explored. The relatively high electrode polarization resistance obtained, 11 Ohm cm2 at 600 ºC, proved the inadequate catalytic activity of this system for hydrogen oxidation. At the end of this thesis...

  11. Formation of Anodic Aluminum Oxide with Branched and Meshed Pores.

    Science.gov (United States)

    Kim, Byeol; Lee, Jin Seok

    2016-06-01

    Anodic aluminum oxide (AAO), with a self-ordered hexagonal array, is important for various applications in nanofabrication including as the fabrication of nanotemplates and other nanostructures. With the consideration, there have been many efforts to control the characteristic parameters of porous anodic alumina by adjustment of the anodizing conditions such as the electrolyte, temperature, applied potential, and Al purity. In particular, impurities in Al are changing the morphology of an alumina film; however, the formation mechanism has not yet been explained. In this work, we anodized a high purity (99.999%, Al(high)) and low purity (99.8%, Al(low)) aluminum foil by a two-step anodization process in an oxalic acid solution or phosphoric acid. It was found that the purity of aluminum foil has influenced the morphology of the alumina film resulting in branched and meshed pores. Also, electrochemical analysis indicated that the branched and meshed pores in the low-purity Al foil formed by the presence of impurities. Impurities act as defects and change the general growth mechanism for pore formation by inducing an electric field imbalance during anodization. This work contributes to the research field of topographical chemistry and applied fields including nanofabrication.

  12. A review of liquid metal anode solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    ALIYA TOLEUOVA

    2013-06-01

    Full Text Available This review discusses recent advances in a solid oxide fuel cell (SOFC variant that uses liquid metal electrodes (anodes with the advantage of greater fuel tolerance and the ability to operate on solid fuel. Key features of the approach are discussed along with the technological and research challenges that need to be overcome for scale-up and commercialisation.

  13. Fabrication of TiO2 Cathodes by Anodic Oxidation for Hydrogen Generation from Electrolysis of Water

    Directory of Open Access Journals (Sweden)

    *İ. Koyuncu

    2014-09-01

    Full Text Available In this investigation, titanium oxide plates were used as cathode for hydrogen production in the aqueous solutions of sulfuric acid, potassium hydroxide, acetic acid and ammonia hydroxides electrolytes separately. Gaseous hydrogen was produced at the cathode and oxygen at the anode. For this purpose, titanium plates were fabricated in acid solution by anodic oxidation. Microstructure of TiO2 nanorod observation was conducted with scanning electron microscopy (SEM. The effects of operating conditions and the electrochemical test parameters, such as electrolytes concentration, temperature, and cell voltage were investigated. Also the performance of TiO2 cathode was compared to zirconium oxide and graphite electrodes. The results show that the highly rated, hydrogen production performance on TiO2 cathode has better than the other electrodes. The maximum rate of hydrogen production is by TiO2 cathode 8.18 ml/ (h. cm2. The cell efficiency for water electrolysis was reached 95% using titanium oxide electrode in 1.5 M H2SO4.

  14. Investigation of anodic oxide coatings on zirconium after heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1 A, 41-500 Chorzów (Poland); Suchanek, Katarzyna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego Street 152, 31-342 Krakow (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment.

  15. Preparation of titanium dioxide films on etched aluminum foil by vacuum infiltration and anodizing

    Science.gov (United States)

    Xiang, Lian; Park, Sang-Shik

    2016-12-01

    Al2O3-TiO2 (Al-Ti) composite oxide films are a promising dielectric material for future use in capacitors. In this study, TiO2 films were prepared on etched Al foils by vacuum infiltration. TiO2 films prepared using a sol-gel process were annealed at various temperatures (450, 500, and 550 °C) for different time durations (10, 30, and 60 min) for 4 cycles, and then anodized at 100 V. The specimens were characterized using X-ray diffraction, field emission scanning electron microscopy, and field emission transmission electron microscopy. The results show that the tunnels of the specimens feature a multi-layer structure consisting of an Al2O3 outer layer, an Al-Ti composite oxide middle layer, and an aluminum hydrate inner layer. The electrical properties of the specimens, such as the withstanding voltage and specific capacitance, were also measured. Compared to specimens without TiO2 coating, the specific capacitances of the TiO2-coated specimens are increased. The specific capacitance of the anode Al foil with TiO2 coating increased by 42% compared to that of a specimen without TiO2 coating when annealed at 550 °C for 10 min. These composite oxide films could enhance the specific capacitance of anode Al foils used in dielectric materials.

  16. Fabrication of TiO2 Crystalline Coatings by Combining Ti-6Al-4V Anodic Oxidation and Heat Treatments

    Directory of Open Access Journals (Sweden)

    María Laura Vera

    2015-01-01

    Full Text Available The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2 layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2 anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment.

  17. Fabrication of TiO2 Crystalline Coatings by Combining Ti-6Al-4V Anodic Oxidation and Heat Treatments

    Science.gov (United States)

    Schvezov, Carlos Enrique; Ares, Alicia Esther

    2015-01-01

    The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2 layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2 anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment. PMID:25784939

  18. Nanoporous anodic titanium dioxide layers as potential drug delivery systems: Drug release kinetics and mechanism.

    Science.gov (United States)

    Jarosz, Magdalena; Pawlik, Anna; Szuwarzyński, Michał; Jaskuła, Marian; Sulka, Grzegorz D

    2016-07-01

    Nanoporous anodic titanium dioxide (ATO) layers on Ti foil were prepared via a three step anodization process in an electrolyte based on an ethylene glycol solution with fluoride ions. Some of the ATO samples were heat-treated in order to achieve two different crystallographic structures - anatase (400°C) and a mixture of anatase and rutile (600°C). The structural and morphological characterizations of ATO layers were performed using a field emission scanning electron microscope (SEM). The hydrophilicity of ATO layers was determined with contact angle measurements using distilled water. Ibuprofen and gentamicin were loaded effectively inside the ATO nanopores. Afterwards, an in vitro drug release was conducted for 24h under a static and dynamic flow conditions in a phosphate buffer solution at 37°C. The drug concentrations were determined using UV-Vis spectrophotometry. The absorbance of ibuprofen was measured directly at 222nm, whether gentamicin was determined as a complex with silver nanoparticles (Ag NPs) at 394nm. Both compounds exhibited long term release profiles, despite the ATO structure. A new release model, based on the desorption of the drug from the ATO top surface followed by the desorption and diffusion of the drug from the nanopores, was derived. The proposed release model was fitted to the experimental drug release profiles, and kinetic parameters were calculated.

  19. An Electrode With Molybdenum-Cathode and Titanium-Anode to Minimize Field Emission Dark Currents

    CERN Document Server

    Nakanishi, T; Gotou, T; Kuwahara, M; Naniwa, K; Okumi, S; Yamamoto, M; Yamamoto, N; Yasui, K

    2004-01-01

    A systematic study to minimize field emission dark currents from high voltage DC electrode has been continued. It is clearly demonstrated that much lower field emissions observed for Molybdenum (Mo) and Titanium (Ti) in comparison to Stainless-steel and Copper. Furthermore, by analyzing gap-length dependence data of the dark current from Mo and Ti, we can find a method to separate the primary field emission currents (FEC) from secondary induced currents (SIC). The latter currents will be created by possible bombardments of metal surface of anode or cathode by electrons or positive ions, respectively. From this data analysis, it is suggested that Mo is suitable for cathode due to its smallest FEC, and Ti is adequate for anode due to relatively small SIC. This prediction was confirmed by our experiment using a pair of Mo and Ti electrode, which showed the total dark current is suppressed below 1 nA at 105 MV/m applied for an area of 7 mm2

  20. Determination of photo conversion efficiency of nanotubular titanium oxide photo-electrochemical cell for solar hydrogen generation

    Science.gov (United States)

    Raja, K. S.; Mahajan, V. K.; Misra, M.

    Anodized and annealed titanium oxide nanotubes show enhanced photo activity and can be used as photo anodes for water electrolysis in hydrogen generation. Application of an external potential to the photo anode is required for enhancement of the photocurrent. This additional electrical energy input complicates the photo conversion efficiency calculation. In this investigation, the photo-electrochemical behavior of anodized titanium oxide nanotubular arrays have been characterized in various electrolytes. Increase in the applied potential increased the photocurrent under illumination with visible light. A simple experimental method for calculating the photo conversion efficiency has been proposed. According to this method, the potential difference between the photo anode and cathode is measured with and without light illumination. The product of the photocurrent and the increase in potential due to light irradiation is considered as the net power output. The photocurrent and the conversion efficiency increased with increase in the pH of the electrolyte. TiO 2 nanotubular arrays annealed at 350 °C for 6 h in nitrogen atmosphere showed a maximum photo conversion efficiency of ∼4% in 1 M KOH electrolyte and ∼3% in 3.5 wt.% sodium chloride solution. The results indicate that nanotubular TiO 2 can be potentially used for the photo electrolysis of seawater to generate hydrogen.

  1. Organic solar cells on indium tin oxide and aluminum doped zinc oxide anodes

    Science.gov (United States)

    Schulze, Kerstin; Maennig, Bert; Leo, Karl; Tomita, Yuto; May, Christian; Hüpkes, Jürgen; Brier, Eduard; Reinold, Egon; Bäuerle, Peter

    2007-08-01

    The authors compare organic solar cells using two different transparent conductive oxides as anode: indium tin oxide (ITO) and three kinds of aluminum doped zinc oxide (ZAO). These anodes with different work functions are used for small molecule photovoltaic devices based on an oligothiophene derivative as donor and fullerene C60 as acceptor molecule. It turns out that cells on ITO and ZAO have virtually identical properties. In particular, the authors demonstrate that the work function of the anode does not influence the Voc of the photovoltaic device due to the use of doped transport layers.

  2. Nanostructured metal oxide-based materials as advanced anodes for lithium-ion batteries.

    Science.gov (United States)

    Wu, Hao Bin; Chen, Jun Song; Hng, Huey Hoon; Lou, Xiong Wen David

    2012-04-21

    The search for new electrode materials for lithium-ion batteries (LIBs) has been an important way to satisfy the ever-growing demands for better performance with higher energy/power densities, improved safety and longer cycle life. Nanostructured metal oxides exhibit good electrochemical properties, and they are regarded as promising anode materials for high-performance LIBs. In this feature article, we will focus on three different categories of metal oxides with distinct lithium storage mechanisms: tin dioxide (SnO(2)), which utilizes alloying/dealloying processes to reversibly store/release lithium ions during charge/discharge; titanium dioxide (TiO(2)), where lithium ions are inserted/deinserted into/out of the TiO(2) crystal framework; and transition metal oxides including iron oxide and cobalt oxide, which react with lithium ions via an unusual conversion reaction. For all three systems, we will emphasize that creating nanomaterials with unique structures could effectively improve the lithium storage properties of these metal oxides. We will also highlight that the lithium storage capability can be further enhanced through designing advanced nanocomposite materials containing metal oxides and other carbonaceous supports. By providing such a rather systematic survey, we aim to stress the importance of proper nanostructuring and advanced compositing that would result in improved physicochemical properties of metal oxides, thus making them promising negative electrodes for next-generation LIBs.

  3. Crystal structure and nanotopographical features on the surface of heat-treated and anodized porous titanium biomaterials produced using selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); FT Innovations BV, Braamsluiper 1, 5831 PW Boxmeer (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); LayerWise NV, Kapeldreef 60, Leuven (Belgium); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 PB 2450, 3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Department of Rheumatology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2014-01-30

    Porous titanium biomaterials manufactured using additive manufacturing techniques such as selective laser melting are considered promising materials for orthopedic applications where the biomaterial needs to mimic the properties of bone. Despite their appropriate mechanical properties and the ample pore space they provide for bone ingrowth and osseointegration, porous titanium structures have an intrinsically bioinert surface and need to be subjected to surface bio-functionalizing procedures to enhance their in vivo performance. In this study, we used a specific anodizing process to build a hierarchical oxide layer on the surface of porous titanium structures made by selective laser melting of Ti6Al4V ELI powder. The hierarchical structure included both nanotopographical features (nanotubes) and micro-features (micropits). After anodizing, the biomaterial was heat treated in Argon at different temperatures ranging between 400 and 600 °C for either 1 or 2 h to improve its bioactivity. The effects of applied heat treatment on the crystal structure of TiO{sub 2} nanotubes and the nanotopographical features of the surface were studied using scanning electron microscopy and X-ray diffraction. It was shown that the transition from the initial crystal structure, i.e. anatase, to rutile occurs between 500 and 600 °C and that after 2 h of heat treatment at 600 °C the crystal structure is predominantly rutile. The nanotopographical features of the surface were found to be largely unchanged for heat treatments carried out at 500 °C or below, whereas they were partially or largely disrupted after heat treatment at 600 °C. The possible implications of these findings for the bioactivity of porous titanium structures are discussed.

  4. Crystal structure and nanotopographical features on the surface of heat-treated and anodized porous titanium biomaterials produced using selective laser melting

    Science.gov (United States)

    Amin Yavari, S.; Wauthle, R.; Böttger, A. J.; Schrooten, J.; Weinans, H.; Zadpoor, A. A.

    2014-01-01

    Porous titanium biomaterials manufactured using additive manufacturing techniques such as selective laser melting are considered promising materials for orthopedic applications where the biomaterial needs to mimic the properties of bone. Despite their appropriate mechanical properties and the ample pore space they provide for bone ingrowth and osseointegration, porous titanium structures have an intrinsically bioinert surface and need to be subjected to surface bio-functionalizing procedures to enhance their in vivo performance. In this study, we used a specific anodizing process to build a hierarchical oxide layer on the surface of porous titanium structures made by selective laser melting of Ti6Al4V ELI powder. The hierarchical structure included both nanotopographical features (nanotubes) and micro-features (micropits). After anodizing, the biomaterial was heat treated in Argon at different temperatures ranging between 400 and 600 °C for either 1 or 2 h to improve its bioactivity. The effects of applied heat treatment on the crystal structure of TiO2 nanotubes and the nanotopographical features of the surface were studied using scanning electron microscopy and X-ray diffraction. It was shown that the transition from the initial crystal structure, i.e. anatase, to rutile occurs between 500 and 600 °C and that after 2 h of heat treatment at 600 °C the crystal structure is predominantly rutile. The nanotopographical features of the surface were found to be largely unchanged for heat treatments carried out at 500 °C or below, whereas they were partially or largely disrupted after heat treatment at 600 °C. The possible implications of these findings for the bioactivity of porous titanium structures are discussed.

  5. Impurity-defect structure of anodic aluminum oxide produced by two-sided anodizing in tartaric acid

    Science.gov (United States)

    Chernyakova, K. V.; Vrublevsky, I. A.; Ivanovskaya, M. I.; Kotsikau, D. A.

    2012-03-01

    Porous aluminum oxide is prepared in a 0.4 M aqueous solution of tartaric acid by two-sided anodizing. Fourier Transform IR spectroscopy (FTIR) data reveal the presence, in the alumina, of unoxidized tartarate ions, as well as products of their partial (radical organic products and CO) and complete (CO2) oxidation. Carboxylate ions and elemental carbon contained in the anodic oxide impart a gray color to the films.

  6. Formation and composition of titanium oxinitride nanocrystals synthesized via nitridizing titanium oxide for nonvolatile memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Li-Wei; Chang, Chun-Yen [Department of Electronics Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan (China); Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw [Department of Physics, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Tu, Chun-Hao; Wang, Pai-Syuan [Department of Electronics Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan (China); Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan (China); Lin, Chao-Cheng [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, 310, Taiwan (China); Chen, Min-Chen [Department of Physics, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Huang, Hui-Chun; Gan, Der-Shin; Ho, New-Jin [Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Chen, Shih-Ching [Department of Physics, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Chen, Shih-Cheng [Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 310, Taiwan, ROC (China); Institute of Electronic Engineering, National Tsing Hua University, Hsinchu, 310, Taiwan (China)

    2011-09-01

    Formation and composition analyses of titanium oxinitride nanocrystals (NCs) fabricated via treating a magnetron co-sputtered thin film of titanium and silicon dioxide with a rapid thermal annealing in nitrogen ambient were demonstrated for nonvolatile memory applications. Phase separation characteristics with different annealing conditions were examined by transmission electron microscopy and chemical bonding characteristics were confirmed by X-ray photon emission spectra. It was observed that a blanket layer composed mainly of titanium oxide was still present as annealing temperature was increased to 700 deg. C, associated with the thermodynamically stable phase of titanium oxide. Furthermore, a higher thermal treatment of 900 deg. C induced formation of a well-separated NC structure and caused simultaneously partial nitridation of the titanium oxide, thereby forming titanium oxinitride NCs. A significant capacitance-voltage hysteresis in threshold voltage shift at 1 V was easily achieved under a small sweeping voltage range of + 2 V/-2 V, and a memory window retention of 2.2 V was obtained after 10{sup 7} s by extrapolation under a 1 s initial-program/erase condition of + 5 V/-5 V, respectively.

  7. Synthesis of self-detached nanoporous titanium-based metal oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hu, F. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Wen, Y. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Chan, K.C., E-mail: mfkcchan@inet.polyu.edu.hk [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Yue, T.M. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Zhou, Y.Z. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Zhu, S.L.; Yang, X.J. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO{sub 3}. The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO{sub 2} (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm{sup 2}, a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC.

  8. Influence of anodic oxidation condition on morphology and photocatalytic performance of titanium dioxide nanotube arrays%阳极氧化条件对氧化钛纳米管阵列形貌及光催化性能的影响

    Institute of Scientific and Technical Information of China (English)

    李桐; 丁士文; 柳涛; 张桢

    2015-01-01

    以阳极氧化法制备了高度有序的 TiO2纳米管阵列,采用扫描电镜观察了不同制备条件下得到的 TiO 2纳米管阵列的微观形貌,分别考察了电解时间、电压、电解液组成对 TiO2纳米管阵列形貌的影响;此外,以酸性红3R 染料作为标志物,测定了制得的 TiO2纳米管阵列片的光催化性能.结果表明,以0.5% NH4 F(质量分数)和乙二醇与水按体积比5∶1混合得到的溶液作为电解液,在15 V 电压下电解2 h ,得到的 TiO2纳米管阵列的纳米管管径适中(60 nm)、大小均一、排列整齐.所制备的 TiO2纳米管阵列对染料的降解率显著优于纳米 TiO 2水溶胶的,且其光催化性能与形貌、电解时间及煅烧温度等密切相关.%Highly ordered titanium dioxide nanotube arrays were prepared by anodic oxidation method .The morphology of TiO2 nanotube arrays obtained under different anodic oxidation conditions was observed with a scanning electron microscope ,and the influences of electrolysis time ,voltage ,and component of electrolyte on the morphology of as‐prepared TiO2 nanotube arrays were investigated .Moreover ,the photocatalytic performance of as‐prepared TiO2 nano‐tube arrays was evaluated with acid‐red 3R as the target compound to be degraded .It was found that ,when 0 .5% N H4 F (mass fraction) and glycol were mixed with water at a volume ratio of 5 ∶ 1 generating the electrolyte ,highly uniform ordered nanotube arrays with a moder‐ate tube diameter of 60 nm were obtained after 2 h electrolysis under a potential of 15 V .Re‐sultant TiO2 nanotube arrays exhibit much better photocatalytic performance than traditional TiO2 hydrosol .Moreover ,the photocatalytic performance of as‐prepared TiO2 nanotube arrays is closely related to the microstructure ,oxidation time ,and calcination temperature .

  9. Corrosion Behavior of Anodic Oxidized TiO2 Film in Seawater

    Institute of Scientific and Technical Information of China (English)

    WANG Min; WANG Wei; HE Benlin; SUN Mingliang; YIN Yansheng; LIU Lan; ZOU Wuyuan; XU Xuefei

    2010-01-01

    TiO2 films were formed on metallic titanium substrates by the anodic oxidation method in H2SO4 solution under the 80V D.C..Phase component and microstructure were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).Water contact angles on titanium oxide film surface were measured under both dark and sunlight illumination conditions.Corrosion tests were carried out in seawater under different illumination conditions by electrochemistry impedance spectrum(EIS)and polarization curves.The result showed that the TiO2 film prepared by the anodic oxidation method was anatase with a uniform structure and without obvious pores or cracks on its surface.The average water contact angle of the film was 116.4 ° in dark,in contrast to an angle of 42.7 ° under the UV illumination for 2 hours,which demonstrates good hydrophobic property.The anti-corrosion behavior of the TiO2 film was declining with the extended immersion time.Under dark conditions,however,the hydrophobic TiO2 film retarded the water infiltrating into the substrate.The impedance changed slowly and the corrosion current density was 2 orders of magnitude lower than that with the film illuminated by sunlight.All of those mentioned above indicate that the TiO2 film possesses much better performance under dark condition,and it can be applied as an engineering material under dark seawater environment.

  10. The efficiency of nanotube formation on titanium anodized under voltage and current control in fluoride/glycerol electrolyte

    Science.gov (United States)

    Valota, A.; LeClere, D. J.; Hashimoto, T.; Skeldon, P.; Thompson, G. E.; Berger, S.; Kunze, J.; Schmuki, P.

    2008-09-01

    The formation of nanotubes on titanium is compared for anodizing under controlled voltage and controlled current in a fluoride/glycerol electrolyte. Rutherford backscattering spectroscopy and nuclear reaction analysis are employed to determine the film compositions. Film morphologies are examined by electron microscopy. The findings reveal films of approximate composition TiO2.0.15TiF4 that probably also contain derivatives of glycerol. Controlled voltage conditions resulted in more uniform final nanotube dimensions, for a particular charge density, and the highest efficiency of film growth, with the charge of the titanium in the film representing ~48% of the charge passed during anodizing. Under current control, the efficiency decreased from ~40% to ~23% with increase of the current density from 0.1 to 0.5 mA cm-2. Further, the thickness of the barrier layer was sometimes enhanced under current control, possibly due to a non-uniform current distribution and consequently elevated local temperature.

  11. Anodic oxides on a beta type Nb-Ti alloy and their characterization by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Woldemedhin, Michael Teka; Hassel, Achim Walter [Max Planck Institut fuer Eisenforschung GmbH, Duesseldorf (Germany); Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University, Linz (Austria); Raabe, Dierk [Max Planck Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    2010-04-15

    Anodic oxides were grown on the surface of an electropolished (Ti-30 at% Nb) beta-titanium ({beta}-Ti) alloy by cyclic voltammetry. The scan rate was 100 mV s{sup -1} between 0 and 8 V in increments of l V in an acetate buffer of pH 6.0. Electrochemical impedance spectroscopy was carried out right after each anodic oxide growth increment to study the electronic properties of the oxide/electrolyte interface in a wide frequency range from 100 kHz to 10 MHz with an AC perturbation voltage of 10 mV. A film formation factor of 2.4 nm V{sup -1} was found and a relative permittivity number (dielectric constant) of 42.4 was determined for the oxide film formed. Mott-Schottky analysis on a potentiostatically formed 7 nm thick oxide film was performed to assess the semiconducting properties of the mixed anodic oxide grown on the alloy. A flat band potential of -0.47 V (standard hydrogen electrode, SHE) was determined, connected to a donor density of 8.2 x 10{sup 17} cm{sup -3}. {beta}-Ti being highly isotropic in terms of mechanical properties should be superior to the stiffer {alpha}-Ti compound. Its application, however, requires a passivation behaviour comparable or better than {alpha}-Ti which in fact is found. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  12. Electron-collecting oxide layers in inverted polymer solar cells via oxidation of thermally evaporated titanium

    Science.gov (United States)

    Zampetti, A.; Salamandra, L.; Brunetti, F.; Reale, A.; Di Carlo, A.; Brown, T. M.

    2016-10-01

    A simple and intuitive deposition technique is discussed to obtain titanium oxide used as an electron collecting layer in polymer solar cells based on the thermal evaporation of pristine titanium and further thermal treatment to convert the metal in oxide. Since the degradation of indium-doped tin oxide at high temperatures is an issue, we demonstrate that the combination of glass/fluorine tin oxide and high temperatures represents a promising approach in the fabrication of inverted polymer solar cells with such a titanium oxide electron collecting layer.

  13. Silver deposition on titanium surface by electrochemical anodizing process reduces bacterial adhesion of Streptococcus sanguinis and Lactobacillus salivarius.

    Science.gov (United States)

    Godoy-Gallardo, Maria; Rodríguez-Hernández, Ana G; Delgado, Luis M; Manero, José M; Javier Gil, F; Rodríguez, Daniel

    2015-10-01

    The aim of this study was to determine the antibacterial properties of silver-doped titanium surfaces prepared with a novel electrochemical anodizing process. Titanium samples were anodized with a pulsed process in a solution of silver nitrate and sodium thiosulphate at room temperature with stirring. Samples were processed with different electrolyte concentrations and treatment cycles to improve silver deposition. Physicochemical properties were determined by X-ray photoelectron spectroscopy, contact angle measurements, white-light interferometry, and scanning electron microscopy. Cellular cytotoxicity in human fibroblasts was studied with lactate dehydrogenase assays. The in vitro effect of treated surfaces on two oral bacteria strains (Streptococcus sanguinis and Lactobacillus salivarius) was studied with viable bacterial adhesion measurements and growth curve assays. Nonparametric statistical Kruskal-Wallis and Mann-Whitney U-tests were used for multiple and paired comparisons, respectively. Post hoc Spearman's correlation tests were calculated to check the dependence between bacteria adhesion and surface properties. X-ray photoelectron spectroscopy results confirmed the presence of silver on treated samples and showed that treatments with higher silver nitrate concentration and more cycles increased the silver deposition on titanium surface. No negative effects in fibroblast cell viability were detected and a significant reduction on bacterial adhesion in vitro was achieved in silver-treated samples compared with control titanium. Silver deposition on titanium with a novel electrochemical anodizing process produced surfaces with significant antibacterial properties in vitro without negative effects on cell viability. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Co-delivery of ibuprofen and gentamicin from nanoporous anodic titanium dioxide layers.

    Science.gov (United States)

    Pawlik, Anna; Jarosz, Magdalena; Syrek, Karolina; Sulka, Grzegorz D

    2017-04-01

    Although single-drug therapy may prove insufficient in treating bacterial infections or inflammation after orthopaedic surgeries, complex therapy (using both an antibiotic and an anti-inflammatory drug) is thought to address the problem. Among drug delivery systems (DDSs) with prolonged drug release profiles, nanoporous anodic titanium dioxide (ATO) layers on Ti foil are very promising. In the discussed research, ATO samples were synthesized via a three-step anodization process in an ethylene glycol-based electrolyte with fluoride ions. The third step lasted 2, 5 and 10min in order to obtain different thicknesses of nanoporous layers. Annealing the as-prepared amorphous layers at the temperature of 400°C led to obtaining the anatase phase. In this study, water-insoluble ibuprofen and water-soluble gentamicin were used as model drugs. Three different drug loading procedures were applied. The desorption-desorption-diffusion (DDD) model of the drug release was fitted to the experimental data. The effects of crystalline structure, depth of TiO2 nanopores and loading procedure on the drug release profiles were examined. The duration of the drug release process can be easily altered by changing the drug loading sequence. Water-soluble gentamicin is released for a long period of time if gentamicin is loaded in ATO as the first drug. Additionally, deeper nanopores and anatase phase suppress the initial burst release of drugs. These results confirm that factors such as morphological and crystalline structure of ATO layers, and the procedure of drug loading inside nanopores, allow to alter the drug release performance of nanoporous ATO layers.

  15. Downscaled anodic oxidation process for aluminium in oxalic acid

    Science.gov (United States)

    Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A.; Lampke, T.

    2017-03-01

    The increasing multi-functionality of parts and assemblies in several fields of engineering demands, amongst others, highly functionalised surfaces. For the different applications, on the one hand, there is a need to scale up surface modification processes originating in the nano- and micro-scale. On the other hand, conventional macro-scale surface refinement methods offer a huge potential for application in the said nano- and micro-scale. The anodic oxidation process, which is established especially for aluminium and its alloys, allows the formation of oxide ceramic layers on the surface. The build-up of an oxide ceramic coating comes along with altered chemical, tribological and electrical surface properties. As a basis for further investigations regarding the use of the anodic oxidation process for micro-scale-manufacturing, the scale effects of oxalic acid anodising on commercially pure aluminium as well as on the AlZn5.5MgCu alloy are addressed in the present work. The focus is on the amount of oxide formed during a potentiostatic process in relation to the exchanged amount of charge. Further, the hardness of the coating as an integral measure to assess the porous oxide structure is approached by nano-indentation technique.

  16. Alternative anode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, John B.; Huang, Yun-Hui [Texas Materials Institute, ETC 9.102, 1 University Station, C2200, The University of Texas at Austin, Austin, TX 78712 (United States)

    2007-11-08

    The electrolyte of a solid oxide fuel cell (SOFC) is an O{sup 2-}-ion conductor. The anode must oxidize the fuel with O{sup 2-} ions received from the electrolyte and it must deliver electrons of the fuel chemisorption reaction to a current collector. Cells operating on H{sub 2} and CO generally use a porous Ni/electrolyte cermet that supports a thin, dense electrolyte. Ni acts as both the electronic conductor and the catalyst for splitting the H{sub 2} bond; the oxidation of H{sub 2} to H{sub 2}O occurs at the Ni/electrolyte/H{sub 2} triple-phase boundary (TPB). The CO is oxidized at the oxide component of the cermet, which may be the electrolyte, yttria-stabilized zirconia, or a mixed oxide-ion/electron conductor (MIEC). The MIEC is commonly a Gd-doped ceria. The design and fabrication of these anodes are evaluated. Use of natural gas as the fuel requires another strategy, and MIECs are being explored for this application. The several constraints on these MIECs are outlined, and preliminary results of this on-going investigation are reviewed. (author)

  17. Barrier and porous anodic oxides on InSb

    Energy Technology Data Exchange (ETDEWEB)

    Suleiman, A.; Hashimoto, T. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: peter.skeldon@manchester.ac.uk; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Echeverria, F. [Dpto de Ing. Metalurgica y de Materiales, Universidad de Antioquia, Oficina 18-240, Calle 67 No. 53-108, A.A. 1226, Medellin (Colombia); Graham, M.J.; Sproule, G.I.; Moisa, S. [Institute for Microstructural Sciences, National Research Council of Canada, Montreal Road, Ottawa, K1A 0R6 (Canada); Habazaki, H. [Graduate Engineering School, Hokkaido University, N13 W8, Kita-ku, Sapporo 060-8628 (Japan); Bailey, P.; Noakes, T.C.Q. [Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom)

    2008-05-15

    Anodizing of InSb at 5 mA cm{sup -2} in sodium tungstate electrolyte is shown to produce barrier-type amorphous oxide at relatively low voltages, to about 40 V, and porous-type amorphous oxide at increased voltages. The barrier-type amorphous oxide, consisting of units of In{sub 2}O{sub 3} and Sb{sub 2}O{sub 3}, distributed relatively uniformly throughout the film, develops at a formation ratio of 2.2 {+-} 0.2 nm V{sup -1}. The outer 15-20% of the film also contains tungsten species. The relatively high efficiency of barrier film growth reduces significantly with transition to porous oxide, which is associated additionally with generation of oxygen at the film surface. The final oxide, at 65 V, comprises pores, of typical diameter 80 nm, orientated approximately normal to the substrate and extending from a barrier region to the film surface.

  18. Formation of titanium dioxide nanotubes on Ti–30Nb–xTa alloys by anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Sil [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Jeong, Yong-Hoon [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State University, Columbus, OH (United States)

    2013-12-31

    The goal of this study was to investigate the formation of titanium dioxide nanotubes on the surface of cast Ti–30Nb–xTa alloys by anodizing. The anodization technique for creating the nanotubes utilized a potentiostat and an electrolyte containing 1 M H{sub 3}PO{sub 4} with 0.8 wt.% NaF. The grain size of the Ti–30Nb–xTa alloys increased as the Ta content increased. Using X-ray diffraction, for the Ti–30Nb alloy the main peaks were identified as α″ martensite with strong peaks of β phase. The phases in the Ti–30Nb–xTa alloys changed from a duplex (α″ + β) microstructure to solely β phase with increasing Ta content. The nanotubes that formed on the surface of the Ti–30Nb–xTa alloys were amorphous TiO{sub 2} without an evidence of the crystalline anatase or rutile forms of TiO{sub 2}. Scanning electron microscopy revealed that the average diameters of the small and large nanotubes on the Ti–30Nb alloy not containing Ta were approximately 100 nm and 400 nm, respectively, whereas the small and large nanotubes on the alloy had diameters of approximately 85 nm and 300 nm, respectively. As the Ta content increased from 0 to 15 wt.%, the average lengths of the nanotubes increased from 2 μm to 3.5 μm. Energy-dispersive X-ray spectroscopy indicated that the nanotubes were principally composed of Ti, Nb, Ta, O and F. Contact angle measurements showed that the nanotube surface had good wettability by water droplets. - Highlights: • TiO{sub 2} nanotube layers on anodized Ti-30Nb-xTa alloys have been investigated. • Nanotube surface had an amorphous structure without heat treatment. • Nanotube diameter of Ti-30Nb-xTa decreased, whereas tube layer increased with Ta content. • The nanotube surface exhibited the low contact angle and good wettability.

  19. Oxidation of Tyrosine-Phosphopeptides by Titanium Dioxide Photocatalysis.

    Science.gov (United States)

    Ruokolainen, Miina; Ollikainen, Elisa; Sikanen, Tiina; Kotiaho, Tapio; Kostiainen, Risto

    2016-06-22

    Protein phosphorylation has a key role in cell regulation. Oxidation of proteins, in turn, is related to many diseases and to aging, but the effects of phosphorylation on the oxidation of proteins and peptides have been rarely studied. The aim of this study was to examine the mechanistic effect of phosphorylation on peptide oxidation induced by titanium dioxide photocatalysis. The effect of phosphorylation was compared between nonphosphorylated and tyrosine phosphorylated peptides using electrospray tandem mass spectrometry. We observed that tyrosine was the most preferentially oxidized amino acid, but the oxidation reaction was significantly inhibited by its phosphorylation. The study also shows that titanium dioxide photocatalysis provides a fast and easy method to study oxidation reactions of biomolecules, such as peptides.

  20. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, R.W.; Muller, R.H.

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  1. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Robert W. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States)

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 - 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  2. Evaluation of anodic behavior of commercially pure titanium in tungsten inert gas and laser welds.

    Science.gov (United States)

    Orsi, Iara Augusta; Raimundo, Larica B; Bezzon, Osvaldo Luiz; Nóbilo, Mauro Antonio de Arruda; Kuri, Sebastião E; Rovere, Carlos Alberto D; Pagnano, Valeria Oliveira

    2011-12-01

    This study evaluated the resistance to corrosion in welds made with Tungsten Inert Gas (TIG) in specimens made of commercially pure titanium (cp Ti) in comparison with laser welds. A total of 15 circular specimens (10-mm diameter, 2-mm thick) were fabricated and divided into two groups: control group-cp Ti specimens (n = 5); experimental group-cp Ti specimens welded with TIG (n = 5) and with laser (n = 5). They were polished mechanically, washed with isopropyl alcohol, and dried with a drier. In the anodic potentiodynamic polarization assay, measurements were taken using a potentiostat/galvanostat in addition to CorrWare software for data acquisition and CorrView for data visualization and treatment. Three curves were made for each working electrode. Corrosion potential values were statistically analyzed by the Student's t-test. Statistical analysis showed that corrosion potentials and passive current densities of specimens welded with TIG are similar to those of the control group, and had lower values than laser welding. TIG welding provided higher resistance to corrosion than laser welding. Control specimens welded with TIG were more resistant to local corrosion initiation and propagation than those with laser welding, indicating a higher rate of formation and growth of passive film thickness on the surfaces of these alloys than on specimens welded with laser, making it more difficult for corrosion to occur. © 2011 by the American College of Prosthodontists.

  3. Ex Situ Investigation of Anisotropic Interconnection in Silicon-Titanium-Nickel Alloy Anode Material

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jong-Soo; Alaboina, Pankaj Kumar; Kang, Chan-Soon; Kim, Seul-Cham; Son, Seoung-Bum; Suh, Soonsung; Kim, Jaehyuk; Kwon, Seunguk; Lee, Se-Hee; Oh, Kyu-Hwan; Cho, Sung-Jin

    2017-03-10

    Herein we investigate the nanostructural evolution of Silicon-Titanium-Nickel (Si-Ti-Ni) ternary alloy material synthesized by melt spinning process for advanced lithium-ion battery anode. The synthesized material was found to have nano-Silicon particles dispersed in the Ti4Ni4Si7 (STN) alloy buffering matrix and was characterized by X-ray diffraction (XRD), High resolution- transmission electron microscope (HR-TEM), Scanning transmission electron microscopes - energy dispersive X-ray spectrometer (STEM-EDS), and electrochemical performance test. The role of STN matrix is to accommodate the volume expansion stresses of the dispersed Si nanoparticles. However, an interesting behavior was observed during cycling. The Si nanoparticles were observed to form interconnection channels growing through the weak STN matrix cracks and evolving to a network isolating the STN matrix into small puddles. This unique nanostructural evolution of Si particles and isolation of the STN matrix failing to offer significant buffering effect to the grown Si network eventually accelerates more volume expansions during cycling due to less mechanical confinement and leads to performance degradation and poor cycle stability.

  4. Titanium oxide nanocoating on a titanium thin film deposited on a glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kotsedi, L., E-mail: kotsedi@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Cummings, F.R. [University of the Western Cape, Electron Microscopy Unit, Physics Department, Bellville 7535, Cape Town (South Africa); Turco, S. Lo; Ntwaeaborwa, O.M. [Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Milano, Italy Via Giovanni Pascoli, 70/3, 20133 Milano (Italy); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)-CNR, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

    2016-03-31

    Thin films of titanium were deposited on a glass substrate using electron beam evaporator. Femtosecond laser pulses were focused on the surface of the films, and the samples were scanned while mounted on the motorized computer-controlled motion stage to produce an areal modification of the films. X-ray diffraction of the laser-patterned samples showed evidence of the formation of a γ-Ti{sub 3}O{sub 5} with a monoclinic phase. Rutherford backscattering spectrometry simulation showed that there is an increase in the oxygen concentration as the average laser fluence is increased. Time of flight secondary ions mass spectrometry analysis showed an even distribution of the titanium and oxygen ions on the sample and also ionized molecules of the oxides of titanium were observed. The formation of the oxide of titanium was further supported using the UV–Vis-NIR spectroscopy, which showed that for 0.1 J/cm{sup 2} fluence, the laser-exposed film showed the electron transfer band and the d–d transition peak of titanium was observed at lower wavelengths. - Highlights: • γ-Ti{sub 3}O{sub 5} formed using femtosecond laser. • Fluence and oxygen relation were studied. • Nanoflakes of γ-Ti{sub 3}O{sub 5} were observed under HRSEM.

  5. The role of stress in self-ordered porous anodic oxide formation and corrosion of aluminum

    Science.gov (United States)

    Capraz, Omer Ozgur

    The phenomenon of plastic flow induced by electrochemical reactions near room temperature is significant in porous anodic oxide (PAO) films, charging of lithium batteries and stress-corrosion cracking (SCC). As this phenomenon is poorly understood, fundamental insight into flow from our work may provide useful information for these problems. In-situ monitoring of the stress state allows direct correlation between stress and the current or potential, thus providing fundamental insight into technologically important deformation and failure mechanisms induced by electrochemical reactions. A phase-shifting curvature interferometry was designed to investigate the stress generation mechanisms on different systems. Resolution of our curvature interferometry was found to be ten times more powerful than that obtained by state-of-art multiple deflectometry technique and the curvature interferometry helps to resolve the conflicting reports in the literature. During this work, formation of surface patterns during both aqueous corrosion of aluminum and formation of PAO films were investigated. Interestingly, for both cases, stress induced plastic flow controls the formation of surface patterns. Pore formation mechanisms during anodizing of the porous aluminum oxide films was investigated . PAO films are formed by the electrochemical oxidation of metals such as aluminum and titanium in a solution where oxide is moderately soluble. They have been used extensively to design numerous devices for optical, catalytic, and biological and energy related applications, due to their vertically aligned-geometry, high-specific surface area and tunable geometry by adjusting process variables. These structures have developed empirically, in the absence of understanding the process mechanism. Previous experimental studies of anodizing-induced stress have extensively focused on the measurement of average stress, however the measurement of stress evolution during anodizing does not provide

  6. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Segura, Sergi, E-mail: sergigarcia@ub.edu [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Keller, Jürg [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Brillas, Enric [Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Radjenovic, Jelena, E-mail: j.radjenovic@awmc.uq.edu.au [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia)

    2015-02-11

    Graphical abstract: - Highlights: • Mineralization of secondary effluent by anodic oxidation with BDD anode. • Complete removal of 29 pharmaceuticals and pesticides at trace level concentrations. • Organochlorine and organobromine byproducts were formed at low μM concentrations. • Chlorine species evolution assessed to evaluate the anodic oxidation applicability. - Abstract: Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl{sup −} ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl{sub 2}/HClO/ClO{sup −}), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO{sup −} species led to the production of ClO{sub 3}{sup −} and ClO{sub 4}{sup −} ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

  7. Manganese titanium perovskites as anodes for solid oxide fuel cells

    OpenAIRE

    2008-01-01

    A new family of perovskite titanates with formulae La4+nSr8-nTi12-nMnnO38 and La4Sr8Ti12-nMnnO38-δ have been investigated as potential fuel electrode materials for SOFCs. The series La4+nSr8-nTi12-nMnnO38 present layered domains within their structure. As such layers appear to have a large negative effect over the electrochemical properties only a few compounds have been characterised. The series La4Sr8Ti12-nMnnO38-δ present a rhombohedral (R-3c) unit cell at room temperature which bec...

  8. Digital data acquisition for a CAD/CAM-fabricated titanium framework and zirconium oxide restorations for an implant-supported fixed complete dental prosthesis.

    Science.gov (United States)

    Lin, Wei-Shao; Metz, Michael J; Pollini, Adrien; Ntounis, Athanasios; Morton, Dean

    2014-12-01

    This dental technique report describes a digital workflow with digital data acquisition at the implant level, computer-aided design and computer-aided manufacturing fabricated, tissue-colored, anodized titanium framework, individually luted zirconium oxide restorations, and autopolymerizing injection-molded acrylic resin to fabricate an implant-supported, metal-ceramic-resin fixed complete dental prosthesis in an edentulous mandible. The 1-step computer-aided design and computer-aided manufacturing fabrication of titanium framework and zirconium oxide restorations can provide a cost-effective alternative to the conventional metal-resin fixed complete dental prosthesis.

  9. Sputtered tin oxide and titanium oxide thin films as alternative transparent conductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Boltz, Janika

    2011-12-12

    Alternative transparent conductive oxides to tin doped indium oxide have been investigated. In this work, antimony doped tin oxide and niobium doped titanium oxide have been studied with the aim to prepare transparent and conductive films. Antimony doped tin oxide and niobium doped titanium oxide belong to different groups of oxides; tin oxide is a soft oxide, while titanium oxide is a hard oxide. Both oxides are isolating materials, in case the stoichiometry is SnO{sub 2} and TiO{sub 2}. In order to achieve transparent and conductive films free carriers have to be generated by oxygen vacancies, by metal ions at interstitial positions in the crystal lattice or by cation doping with Sb or Nb, respectively. Antimony doped tin oxide and niobium doped titanium oxide films have been prepared by reactive direct current magnetron sputtering (dc MS) from metallic targets. The process parameters and the doping concentration in the films have been varied. The films have been electrically, optically and structurally analysed in order to analyse the influence of the process parameters and the doping concentration on the film properties. Post-deposition treatments of the films have been performed in order to improve the film properties. For the deposition of transparent and conductive tin oxide, the dominant parameter during the deposition is the oxygen content in the sputtering gas. The Sb incorporation as doping atoms has a minor influence on the electrical, optical and structural properties. Within a narrow oxygen content in the sputtering gas highly transparent and conductive tin oxide films have been prepared. In this study, the lowest resistivity in the as deposited state is 2.9 m{omega} cm for undoped tin oxide without any postdeposition treatment. The minimum resistivity is related to a transition to crystalline films with the stoichiometry of SnO{sub 2}. At higher oxygen content the films turn out to have a higher resistivity due to an oxygen excess. After post

  10. Microstructure and optical appearance of anodized friction stir processed Al - Metal oxide surface composites

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate Ti, Y and Ce oxide powders into the surface of an Aluminium alloy. The FSP processed surface composite was subsequently anodized with an aim to develop optical effects in the anodized layer owing to the presence of incorporated...... oxide particles which will influence the scattering of light. This paper presents the investigations on relation between microstructure of the FSP zone and optical appearance of the anodized layer due to incorporation of metal oxide particles and modification of the oxide particles due to the anodizing...

  11. Ammonium removal from landfill leachate by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Cabeza, Adelaida [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain); Urtiaga, Ane [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain)]. E-mail: urtiaga@unican.es; Rivero, Maria-Jose [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain); Ortiz, Inmaculada [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain)

    2007-06-18

    The feasibility of removing ammonium from landfill leachates by electrochemical oxidation was studied. Raw leachates and biologically/physico-chemically pretreated leachates from a municipal landfill site were treated. Boron doped diamond was used as anode and stainless steel as cathode, both electrodes with an area of 70 cm{sup 2}. The effects of the applied current density (15-90 mA cm{sup -2}), the initial ammonium concentration (480-2000 mg L{sup -1}), and the initial chloride concentration were experimentally studied. Total ammonium removal was obtained after 360 min of processing and almost half of the initial ammonium nitrogen was oxidized to nitrate. On the other hand, the concentration of chloride enhanced the rate of ammonium oxidation. In addition, the amount of N-NH{sub 4} {sup +} transformed into N-NO{sub 3} {sup -} decreased when additional chloride was provided.

  12. Co-doped titanium oxide foam and water disinfection device

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Jian-Ku; Wu, Pinggui; Xie, Rong-Cai

    2016-01-26

    A quaternary oxide foam, comprises an open-cell foam containing (a) a dopant metal, (b) a dopant nonmetal, (c) titanium, and (d) oxygen. The foam has the advantages of a high surface area and a low back pressure during dynamic flow applications. The inactivation of Escherichia coli (E. coli) was demonstrated in a simple photoreactor.

  13. Controlling interferometric properties of nanoporous anodic aluminium oxide.

    Science.gov (United States)

    Kumeria, Tushar; Losic, Dusan

    2012-01-26

    A study of reflective interference spectroscopy [RIfS] properties of nanoporous anodic aluminium oxide [AAO] with the aim to develop a reliable substrate for label-free optical biosensing is presented. The influence of structural parameters of AAO including pore diameters, inter-pore distance, pore length, and surface modification by deposition of Au, Ag, Cr, Pt, Ni, and TiO2 on the RIfS signal (Fabry-Perot fringe) was explored. AAO with controlled pore dimensions was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid at different voltages (30 to 70 V) and anodization times (10 to 60 min). Results show the strong influence of pore structures and surface modifications on the interference signal and indicate the importance of optimisation of AAO pore structures for RIfS sensing. The pore length/pore diameter aspect ratio of AAO was identified as a suitable parameter to tune interferometric properties of AAO. Finally, the application of AAO with optimised pore structures for sensing of a surface binding reaction of alkanethiols (mercaptoundecanoic acid) on gold surface is demonstrated.

  14. Electrochemical degradation of clofibric acid in water by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sires, Ignasi [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Cabot, Pere Lluis [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Centellas, Francesc [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Garrido, Jose Antonio [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Rodriguez, Rosa Maria [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Arias, Conchita [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Brillas, Enric [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)]. E-mail: brillas@ub.edu

    2006-10-05

    Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical ({center_dot}OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl{sub 2}. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with {center_dot}OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO{sub 2} with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.

  15. Method for preparing hydrous titanium oxide spherules and other gel forms thereof

    Science.gov (United States)

    Collins, J.L.

    1998-10-13

    The present invention are methods for preparing hydrous titanium oxide spherules, hydrous titanium oxide gels such as gel slabs, films, capillary and electrophoresis gels, titanium monohydrogen phosphate spherules, hydrous titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite sorbent, titanium monohydrogen phosphate spherules having suspendible particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, titanium oxide spherules in the form of anatase, brookite or rutile, titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite, hydrous titanium oxide fiber materials, titanium oxide fiber materials, hydrous titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite, titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite and spherules of barium titanate. These variations of hydrous titanium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters and ceramics. 6 figs.

  16. Modification of the titanium oxide morphology and composition by a combined chemical-electrochemical treatment on cp Ti

    Directory of Open Access Journals (Sweden)

    Ernesto Peláez-Abellán

    2012-02-01

    Full Text Available A combined chemical-electrochemical oxidation method to obtain porous bioactive TiO2 films on titanium is reported. In this case, a titanium chemical pre-etching followed by the micro-arc oxidation (MAO treatment is proposed and optimized, to obtain a high-roughness and porous surface which benefits the titanium/bone integration. The MAO treatment at various rates (different current densities allowed to define the influence of the oxide growth rate on the surface morphology and to design the best features for each case. Titanium samples were pre-etched using a 2% HF solution as a function of the etching time, and then anodized by the MAO treatment in a 0.5 M H3PO4 solution at current densities in the 10 to 90 mA.cm-2 range. High porosity (0.5 to 1 µm-diameter pores and higher phosphorous content for TiO2 films were achieved by first etching the Ti sample for 180 seconds in the HF solution, and then applying current densities in the 80 to 90 mA.cm-2 range for the micro-arc oxidation process.

  17. Synthesis of bio-active titanium oxide coatings stimulated by electron-beam plasma

    Directory of Open Access Journals (Sweden)

    Vasilieva Tatiana

    2014-11-01

    Full Text Available Advantages of the electron-beam plasma (EBP for production of bioactive titanium oxide coatings were experimentally studied. The coatings were synthesized in EBP of oxygen on the surface of plane titanium substrates. A number of analytical techniques were used to characterize morphology, chemical composition, and structure of the synthesized titanium oxide. The analysis showed the titanium oxide (IV in the rutile form to predominate in the coatings composition.

  18. Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Asoh, Hidetaka [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)], E-mail: asoh@cc.kogakuin.ac.jp; Uchibori, Kota; Ono, Sachiko [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)

    2009-07-15

    The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

  19. Analogy and differences between aluminium and titanium electrowinning

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2006-09-01

    Full Text Available to produce product meeting industrial titanium specifications.  Two early patents in this field disclose a process conceived by Donahue et al8,9. Donahue and his co- workers described a method and apparatus to produce molten titanium electrolytically via... to use a consumable titanium oxide anode that becomes electrically conductive at high temperatures.  Larson et al13 described an experiment using a plasma as anode avoiding direct contact of carbon with the electrolyte.  Cardarelli14 disclosed...

  20. Titanium oxide nanotubes: Synthesis, properties and applications for solar energy harvesting

    Science.gov (United States)

    Panaitescu, Eugen

    Titanium oxide (titania) nanotubes, although relatively recently discovered (less than 15 years ago), have already shown great promise regarding solar energy harvesting applications, exhibiting very good photocatalytic and photovoltaic properties. An alternative anodization route for production of titania nanotubes at the surface of a titanium foil using chloride ions as catalyst instead of the routinely used highly toxic fluorides, is presented in this work. Moreover, the fabrication parameters are extensively studied, thus providing both an insight into the synthesis mechanism and hints towards possible process optimization routes. Although not forming uniformly over the sample surface and lacking long range ordering, very high aspect ratio (over 1000:1) nanotubes are rapidly formed (in minutes) by a self assembling mechanism. Thus, the method is a viable alternative route for the fast production of partially ordered titania nanotubes, both as films on top of a titanium foil, or as microscopic grains (powders or suspended in solutions). Since the as formed nanotubes are amorphous, attention is also given to the crystallization process, especially in the case of poorly studied powders. Attachment of other nanostructures such as cadmium telluride quantum dots, bio-composites (proteins), or gold nanoparticles for the synthesis of hybrid materials combining properties of both composites have been studied too. Also, possible applications of these new materials in two solar energy technologies: photovoltaic electricity generation using dye sensitized solar cells (DSSC's), and hydrogen production by the photoelectrochemical (PEC) splitting of water are investigated.

  1. Comparative study on ammonia oxidation over Ni-based cermet anodes for solid oxide fuel cells

    Science.gov (United States)

    Molouk, Ahmed Fathi Salem; Yang, Jun; Okanishi, Takeou; Muroyama, Hiroki; Matsui, Toshiaki; Eguchi, Koichi

    2016-02-01

    In the current work, we investigate the performance of solid oxide fuel cells (SOFCs) with Ni‒yttria-stabilized zirconia (Ni-YSZ) and Ni‒gadolinia-dope ceria (Ni-GDC) cermet anodes fueled with H2 or NH3 in terms of the catalytic activity of ammonia decomposition. The cermet of Ni-GDC shows higher catalytic activity for ammonia decomposition than Ni-YSZ. In response to this, the performance of direct NH3-fueled SOFC improved by using Ni-GDC anode. Moreover, we observe further enhancement in the cell performance and the catalytic activity for ammonia decomposition with applying Ni-GDC anode synthesised by the glycine-nitrate combustion process. These results reveal that the high performance of Ni-GDC anode for the direct NH3-fueled SOFC results from its mixed ionic-electronic conductivity as well as high catalytic activity for ammonia decomposition.

  2. Osseointegration improvement by plasma electrolytic oxidation of modified titanium alloys surfaces.

    Science.gov (United States)

    Echeverry-Rendón, Mónica; Galvis, Oscar; Quintero Giraldo, David; Pavón, Juan; López-Lacomba, José Luis; Jiménez-Piqué, Emilio; Anglada, Marc; Robledo, Sara M; Castaño, Juan G; Echeverría, Félix

    2015-02-01

    Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.

  3. Anodic deposition of hydrous ruthenium oxide for supercapacitors

    Science.gov (United States)

    Hu, Chi-Chang; Liu, Ming-Jue; Chang, Kuo-Hsin

    This communication demonstrates the success in the anodic deposition of hydrous ruthenium oxide (denoted as RuO 2· xH 2O) from RuCl 3· xH 2O in aqueous media with/without adding acetate ions (CH 3COO -, AcO -) as the complex agent. The benefits of as-deposited RuO 2· xH 2O include the low electron-hopping resistance and the low contact resistance at the Ti-RuO 2· xH 2O interface which are clarified in electrochemical impedance spectroscopic (EIS) studies. The cycling stability, specific capacitance, and power performance of as-deposited RuO 2· xH 2O are further improved by annealing in air at 150 °C for 2 h. The morphologies of as-deposited and annealed RuO 2· xH 2O films, examined by scanning electron microscopy (SEM), are very similar to that of thermally decomposed RuO 2. The high onset frequencies of 660 and 1650 Hz obtained from EIS spectra for the as-deposited and annealed RuO 2· xH 2O films, respectively, definitely illustrate the high-power merits of both oxide films prepared by means of the anodic deposition without considering the advantages of its simplicity, one-step, reliability, low cost, and versatility for electrode preparation.

  4. Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes

    Science.gov (United States)

    Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

    2016-02-01

    We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials.

  5. Solid oxide fuel cell power plant with an anode recycle loop turbocharger

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.

    2016-09-27

    An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).

  6. Formation and dielectric properties of anodic oxide films on Zr–Al alloys

    OpenAIRE

    Koyama, Shun; Aoki, Yoshitaka; Nagata, Shinji; Habazaki, Hiroki

    2011-01-01

    Zr–Al alloys containing up to 26 at.% aluminum, prepared by magnetron sputtering, have been anodized in 0.1 mol dm−3 ammonium pentaborate electrolyte, and the structure and dielectric properties of the resultant anodic oxide films have been examined by grazing incidence X-ray diffraction, transmission electron microscopy, Rutherford backscattering spectroscopy, and AC impedance spectroscopy. The anodic oxide film formed on zirconium consists of monoclinic and tetragonal ZrO2 with the fo...

  7. Investigation of the Surface Properties of Titanium Biomaterial with Oxide Layer of Rutile Structure

    Institute of Scientific and Technical Information of China (English)

    Huang Nan; Chen Yuanru; Xiao Jing; Xue Zhennan; Liu Xianghuai

    1994-01-01

    Structural characteristics of titanium oxide layer on titanium matrix were investigated by Rutherford Backscattering Spectroscopy (RBS), Auger Electron Spectroscopy(AES) and X-ray diffraction, It has been identified that the titanium oxide layers have rutile structure. The mechanical properties of its surface were ineasured by microhardness test, pin-on-disc wear experiment and scratch adhesion test. The blood-compatibility of the titanium oxide layers of different thickness was studied by blood clotting time measurement. It is shown that as the thickness of the titanium oxide layers increases, the surface mechanical properties and bloodcompatibility of these layers are obviously improved.

  8. Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in arabidopsis

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that e...

  9. Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in arabidopsis

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that e...

  10. AFM based anodic oxidation and its application to oxidative cutting and welding of CNT

    Institute of Scientific and Technical Information of China (English)

    JIAO NianDong; WANG YueChao; XI Ning; DONG ZaiLi

    2009-01-01

    Probe anodic oxidation by atomic force microscope (AFM) is one of the most important techniques in fabricating nano structures and devices.The technique was further studied in this paper.By analyzing the distribution of the electric field on substrate surface the dependence of oxide characters on field was discussed.The impacts of various parameters on oxide fabrication were experimentally studied.Based on these studies, we realized the oxidative cutting and welding of carbon nanotube (CNT) by the AFM based oxidation technique and provided a novel technique for the assembly and fabrication of CNT based nano devices.

  11. AFM based anodic oxidation and its application to oxidative cutting and welding of CNT

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Probe anodic oxidation by atomic force microscope (AFM) is one of the most important techniques in fabricating nano structures and devices. The technique was further studied in this paper. By analyzing the distribution of the electric field on substrate surface the dependence of oxide characters on field was discussed. The impacts of various parameters on oxide fabrication were experimentally studied. Based on these studies, we realized the oxidative cutting and welding of carbon nanotube (CNT) by the AFM based oxidation technique and provided a novel technique for the assembly and fabrication of CNT based nano devices.

  12. OXIDATION OF DRY HYDROCARBONS AT HIGH-POWER DENSITY ANODES

    Energy Technology Data Exchange (ETDEWEB)

    K.Krist; O. Spaldon-Stewart; R. Remick

    2004-03-01

    This work builds upon discoveries by the University of Pennsylvania and others pertaining to the oxidation of dry hydrocarbon fuels in high temperature solid oxide fuel cells. The work reported here was restricted primarily to dry methane and confirms that YSZ-based cells, having ceria in the anode as a catalyst and copper in the anode as a current collector, can operate on dry methane for extended periods. Thirty-three lab-scale cells of various designs were fabricated and operated under a variety of conditions. The longest-lived cell gave stable performance on dry methane at 800 C for over 305 hours. Only slight carbon deposition was noted at the completion of the test. A corresponding nickel/YSZ-based anode would have lasted for less than an hour under these test conditions (which included open circuit potential measurements) before carbon fouling essentially destroyed the cell. The best performing cell achieved 112 mW/cm{sub 2} on dry methane at 800 C. Several problems were encountered with carbon fouling and declining open circuit voltages in many of the test cells after switching from operation on hydrogen to dry methane. Although not rigorously confirmed by experimentation, the results suggested that air infiltration through less than perfect perimeter seals or pinholes in the electrolytes, or both gave rise to conditions that caused the carbon fouling and OCV decline. Small amounts of air reacting with methane in a partial oxidation reaction could produce carbon monoxide that, in turn, would deposit the carbon. If this mechanism is confirmed, it implies that near perfect hardware is required for extended operation. Some evidence was also found for the formation of electrical shorts, probably from carbon deposits bridging the electrolyte. Work with odorized methane and with methane containing 100-ppm hydrogen sulfide confirmed that copper is stable at 800 C in dry hydrocarbon fuels in the presence of sulfur. In a number of cases, but not exclusively, the

  13. Characterization and Tribological Properties of Hard Anodized and Micro Arc Oxidized 5754 Quality Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    M. Ovundur

    2015-03-01

    Full Text Available This study was initiated to compare the tribological performances of a 5754 quality aluminum alloy after hard anodic oxidation and micro arc oxidation processes. The structural analyses of the coatings were performed using XRD and SEM techniques. The hardness of the coatings was determined using a Vickers micro-indentation tester. Tribological performances of the hard anodized and micro arc oxidized samples were compared on a reciprocating wear tester under dry sliding conditions. The dry sliding wear tests showed that the wear resistance of the oxide coating generated by micro arc oxidation is remarkably higher than that of the hard anodized alloy.

  14. Photoelectrochemical properties of sol–gel obtained titanium oxide

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2008-12-01

    Full Text Available The photoelectrochemical properties of a sol–gel prepared titanium oxide coating applied onto a Ti substrate were investigated. The oxide coating was formed from an inorganic sol thermally treated in air at 350 °C. The coating consisted of agglomerates of narrow size distribution around 100 nm. The photoelectrochemical characteristics were evaluated by investigating the changes in the open circuit potential, current transients and impedance characteristics of a Ti/TiO2 electrode upon illumination by UV light in H2SO4 solution and in the oxidation of benzyl alcohol. The electrode was found to be active for photoelectrochemical reactions in the investigated solutions.

  15. Development of RuO2/TiO2 titanium anodes and a device for in situ active chlorine generation

    Directory of Open Access Journals (Sweden)

    Spasojević Miroslav D.

    2013-01-01

    Full Text Available Chlorine is used worldwide for water disinfection purposes. However, due to its toxicity the EU has imposed a set of standards that must be applied when transporting and storing chlorine. In Serbia, numerous studies have been conducted attempting to develop the technology for the generation of active chlorine disinfectant but with a non-toxic aqueous solution of sodium chloride as the raw material. This study provides an overview of the titanium anodes activated by thermally obtained solid solution of ruthenium and titanium oxide development. It also presents new findings on the effect of the temperature of thermal treatment, the composition, the thickness of an active coating on its microstructural properties, and consequently on the catalytic activity, ion selectivity, and corrosion stability during active chlorine generation through the electrolysis of dilute sodium chloride solutions at room temperature. The study also evaluates the effect of the kinetic and operational parameters of the electrochemical process of active chlorine generation on both current and energy efficiencies. The results obtained were used to determine optimal values of technological parameters of the production process. This comprehensive research resulted in the construction of different types of remote-controlled and fully automated active chlorine generating plants.

  16. Beneficiation of Titanium Oxides From Ilmenite by Self-Reduction of Coal Bearing Pellets

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide slag beneficiated was separated from metal iron. The effect of temperature, flux and coal blending ratio on the reduction and separation was investigated, and rational parameters were determined. A new process for the beneficiation of titanium oxides by rotary hearth furnace (RHF) was proposed.

  17. Electrode Reaction Pathway in Oxide Anode for Solid Oxide Fuel Cells

    Science.gov (United States)

    Li, Wenyuan

    Oxide anodes for solid oxide fuel cells (SOFC) with the advantage of fuel flexibility, resistance to coarsening, small chemical expansion and etc. have been attracting increasing interest. Good performance has been reported with a few of perovskite structure anodes, such as (LaSr)(CrMn)O3. However, more improvements need to be made before meeting the application requirement. Understanding the oxidation mechanism is crucial for a directed optimization, but it is still on the early stage of investigation. In this study, reaction mechanism of oxide anodes is investigated on doped YCrO 3 with H2 fuel, in terms of the origin of electrochemical activity, rate-determining steps (RDS), extension of reactive zone, and the impact from overpotential under service condition to those properties. H2 oxidation on the YCs anodes is found to be limited by charge transfer and H surface diffusion. A model is presented to describe the elementary steps in H2 oxidation. From the reaction order results, it is suggested that any models without taking H into the charge transfer step are invalid. The nature of B site element determines the H2 oxidation kinetics primarily. Ni displays better adsorption ability than Co. However, H adsorption ability of such oxide anode is inferior to that of Ni metal anode. In addition, the charge transfer step is directly associated with the activity of electrons in the anode; therefore it can be significantly promoted by enhancement of the electron activity. It is found that A site Ca doping improves the polarization resistance about 10 times, by increasing the activity of electrons to promote the charge transfer process. For the active area in the oxide anode, besides the traditional three-phase boundary (3PB), the internal anode surface as two-phase boundary (2PB) is proven to be capable of catalytically oxidizing the H2 fuel also when the bulk lattice is activated depending on the B site elements. The contribution from each part is estimated by switching

  18. Performance evaluation of titanium dioxide based dye-sensitized solar cells under the influence of anodization steps, nanotube length and ionic liquid-free redox electrolyte solvents

    Science.gov (United States)

    Cheong, Y. L.; Beh, K. P.; Yam, F. K.; Hassan, Z.

    2016-06-01

    In this work, highly ordered titanium dioxide (TiO2) nanotube (NT) arrays were synthesized on titanium foil using electrochemical anodization method. The morphological aspects of the nanotubes based on different anodization duration and number of anodization steps (maximum two) have been investigated. The nanotube arrays subsequently used as photoanode in a dye-sensitized solar cell (DSSC) assembly. The studies on the effects of different solvents for triiodide/iodide redox electrolyte and NT length towards the performance of DSSC were conducted. It is known that electrolyte solvent can significantly affect the photovoltaic conversion efficiency. It is noteworthy that longer NT length tends to yield higher efficiency due to better dye adsorption. However, when the NTs exceeded certain length the efficiency decreases instead. Meanwhile, a comparison of DSSC performance based on number of anodization steps on titanium was performed. Highly ordered NT arrays could be obtained using two-steps anodization, which proved to have positive effects on the DSSC performance. The highest photovoltaic conversion efficiency in this work is 2.04%, achieved by two-step anodization. The corresponding average nanotubes length was ˜18 μm, with acetonitrile (ACN) as the redox electrolyte solvent.

  19. The efficiency of nanotube formation on titanium anodized under voltage and current control in fluoride/glycerol electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Valota, A; LeClere, D J; Hashimoto, T; Skeldon, P; Thompson, G E [Corrosion and Protection Centre, School of Materials, The University of Manchester, PO Box 88, Manchester M60 1QD (United Kingdom); Berger, S; Kunze, J; Schmuki, P [Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martenstrasse 7, D-91058 Erlangen (Germany)

    2008-09-03

    The formation of nanotubes on titanium is compared for anodizing under controlled voltage and controlled current in a fluoride/glycerol electrolyte. Rutherford backscattering spectroscopy and nuclear reaction analysis are employed to determine the film compositions. Film morphologies are examined by electron microscopy. The findings reveal films of approximate composition TiO{sub 2}.0.15TiF{sub 4} that probably also contain derivatives of glycerol. Controlled voltage conditions resulted in more uniform final nanotube dimensions, for a particular charge density, and the highest efficiency of film growth, with the charge of the titanium in the film representing {approx}48% of the charge passed during anodizing. Under current control, the efficiency decreased from {approx}40% to {approx}23% with increase of the current density from 0.1 to 0.5 mA cm{sup -2}. Further, the thickness of the barrier layer was sometimes enhanced under current control, possibly due to a non-uniform current distribution and consequently elevated local temperature.

  20. Effects of airborne-particle abrasion, sodium hydroxide anodization, and electrical discharge machining on porcelain adherence to cast commercially pure titanium.

    Science.gov (United States)

    Acar, Asli; Inan, Ozgür; Halkaci, Selçuk

    2007-07-01

    The aim of this study was to determine the effect of airborne-particle abrasion (APA), sodium hydroxide anodization (SHA), and electrical discharge machining (EDM) on cast titanium surfaces and titanium-porcelain adhesion. Ninety titanium specimens were cast with pure titanium and the alpha-case layer was removed. Specimens were randomly divided into three groups. Ten specimens from each group were subjected to APA. SHA was applied to the second subgroups, and the remaining specimens were subjected to the EDM. For the control group, 10 specimens were cast using NiCr alloy and subjected to only APA. Surfaces were examined by using scanning electron microscope and a surface profilometer. Three titanium porcelains were fused on the titanium surfaces, whereas NiCr specimens were covered with conventional porcelain. Titanium-porcelain adhesion was characterized by a 3-point bending test. Statistical analysis showed that the porcelain-metal bond strength of the control group was higher than that of the titanium-porcelain system (p < 0.05). There were no significant differences between the bond strengths of titanium groups (p 0.05), except the bond strengths of Noritake Super Porcelain TI-22 groups on which APA and SHA were applied (p < 0.05). SHA and EDM as surface treatment did not improve titanium-porcelain adhesion when compared to APA.

  1. An X-ray diffraction study of titanium oxidation

    Science.gov (United States)

    Wiedemann, K. E.; Unnam, J.

    1984-01-01

    Titanium specimens of commercial purity were exposed at 1100 to 1400 F to laboratory air for times up to 100 hours. The extent of substrate contamination by interstitial oxygen was was determined by a new X-ray diffraction analysis involving transformation of X-ray diffraction intensity bands. The oxygen solid-solubility at the oxide-metal interfaces and its variation with time at temperature were also determined. Diffusion coefficients are deduced from the oxygen depth profiles.

  2. Titanium-oxide nanomaterials: synthesis, characterization, and selective photocatalysis

    OpenAIRE

    Ainikalkannath Lazar, Manoj

    2017-01-01

    The side effects of some recent scientific advances challenge the well-being of our planet. Water contamination, one of these side effects, from industrial effluents is a major source of fresh water pollution. Semiconductor photocatalysis, which operates under ultraviolet or visible light irradiation, is a well proven approach to water de-contamination. Among the various available semiconductor photocatalysts, nanocrystalline titanium-oxides are unique in their activity, stability and biocomp...

  3. Investigation of top-emitting OLEDs using molybdenum oxide as anode buffer layer

    Institute of Scientific and Technical Information of China (English)

    LIN Hui; YU Jun-sheng; ZHANG Wei

    2012-01-01

    A high-effective bottom anode is essential for high-performance top-emitting organic light-emitting devices (OLEDs).In this paper,Ag-based top-emitting OLEDs are investigated.Ag has the highest reflectivity for visible light among all metals,yet its hole-injection properties are not ideal for anodes of top-emitting OLED.The performance of the devices is significantly improved using the molybdenum oxide as anode buffer layer at the surface of Ag.By introducing the molybdenum oxide,the hole injection from Ag anodes into top-emitting OLED is largely enhanced with rather high reflectivity retained.

  4. Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide

    Directory of Open Access Journals (Sweden)

    Lanza Marcos Roberto V.

    2002-01-01

    Full Text Available This paper presents a study of the performance of two commercial dimensionally stable anode (DSA® oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidation of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

  5. Fabrication of Nanostructured PLGA Scaffolds Using Anodic Aluminum Oxide Templates

    CERN Document Server

    Hsueh, Cheng-Chih; Hsu, Shan-Hui; Hung, Huey-Shan

    2008-01-01

    PLGA (poly(lactic-co-glycolic acid)) is one of the most used biodegradable and biocompatible materials. Nanostructured PLGA even has great application potentials in tissue engineering. In this research, a fabrication technique for nanostructured PLGA membrane was investigated and developed. In this novel fabrication approach, an anodic aluminum oxide (AAO) film was use as the template ; the PLGA solution was then cast on it ; the vacuum air-extraction process was applied to transfer the nano porous pattern from the AAO membrane to the PLGA membrane and form nanostures on it. The cell culture experiments of the bovine endothelial cells demonstrated that the nanostructured PLGA membrane can double the cell growing rate. Compared to the conventional chemical-etching process, the physical fabrication method proposed in this research not only is simpler but also does not alter the characteristics of the PLGA. The nanostructure of the PLGA membrane can be well controlled by the AAO temperate.

  6. Fabrication of YBCO nanowires with anodic aluminum oxide (AAO) template

    Energy Technology Data Exchange (ETDEWEB)

    Dadras, Sedigheh, E-mail: dadras@alzahra.ac.ir; Aawani, Elaheh

    2015-10-15

    We have fabricated YBCO nanowires by using anodic aluminum oxide (AAO) template and sol–gel method, to investigate the fundamental properties of the one-dimensional nanostructure YBCO high-temperature superconductor and enhance its applications. The field-emission scanning electron microscopy and X-ray diffraction pattern results have shown forming of Y-123 nanowires in the template. As an outcome, the YBCO nanowires, prepared by dipping AAO template into YBCO sol method, have average diameter of about 38 nm and length of 1 μm; this is an optimum nanowire sample with larger diameter and length. The resistance–temperature measurement indicates that the onset critical temperature of these samples occurs at 91 K, and the resistance of the optimum sample at onset transition is 10 times lower than the other sample.

  7. Electrical transport through single-wall carbon nanotube-anodic aluminum oxide-aluminum heterostructures

    Science.gov (United States)

    Kukkola, Jarmo; Rautio, Aatto; Sala, Giovanni; Pino, Flavio; Tóth, Géza; Leino, Anne-Riikka; Mäklin, Jani; Jantunen, Heli; Uusimäki, Antti; Kordás, Krisztián; Gracia, Eduardo; Terrones, Mauricio; Shchukarev, Andrey; Mikkola, Jyri-Pekka

    2010-01-01

    Aluminum foils were anodized in sulfuric acid solution to form thick porous anodic aluminum oxide (AAO) films of thickness ~6 µm. Electrodes of carboxyl-functionalized single-wall carbon nanotube (SWCNT) thin films were inkjet printed on the anodic oxide layer and the electrical characteristics of the as-obtained SWCNT-AAO-Al structures were studied. Nonlinear current-voltage transport and strong temperature dependence of conduction through the structure was measured. The microstructure and chemical composition of the anodic oxide layer was analyzed using transmission and scanning electron microscopy as well as x-ray photoelectron spectroscopy. Schottky emission at the SWCNT-AAO and AAO-Al interfaces allowed by impurity states in the anodic aluminum oxide film together with ionic surface conduction on the pore walls of AAO gives a reasonable explanation for the measured electrical conduction. Calcined AAO is proposed as a dielectric material for SWCNT-field effect transistors.

  8. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mendzik K.

    2010-06-01

    Full Text Available Oxidation is one of the most employed methods to improve titanium and its alloys properties especially due to medical application. This process like most of the thermochemical treatment processes substantially influences on the characteristic of surface layers and the same on its mechanical and useful properties. Oxide coatings produced during titanium oxidation were examined due to their composition identification. Titanium was oxidized in fluidized bed in temperature range between 500÷700°C. Microstructures of titanium with a visible oxide coating on its surface after thermochemical treatment and changes of grain size in core of titanium samples are described. Moreover Xray phase analysis of obtained oxides coatings was made as well as microhardness measurements of titanium surface layers after oxidation process. Finally, the surfaces of titanium after oxidation in fluidized bed were measured by Auger electron spectroscopy. All research results are used to built numerical model of oxidation process in fluidized. Titanium oxidation process in fluidized bed is very complicated, because changes of parameters are non linear characteristics. This fact and lack of mathematical algorithms describing this process makes modeling properties of titanium elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling oxidizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties.

  9. Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

    Science.gov (United States)

    Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei

    2015-02-01

    Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

  10. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus;

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates of the ca...

  11. In-situ electrochemical doping of nanoporous anodic aluminum oxide with indigo carmine organic dye

    Energy Technology Data Exchange (ETDEWEB)

    Stępniowski, Wojciech J., E-mail: wojciech.stepniowski@wat.edu.pl [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Norek, Małgorzata [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Budner, Bogusław [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Michalska-Domańska, Marta [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Nowak-Stępniowska, Agata; Bombalska, Aneta; Kaliszewski, Miron [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Mostek, Anna [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Thorat, Sanjay; Salerno, Marco [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, Genova I-16163 (Italy); Giersig, Michael [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Bojar, Zbigniew [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland)

    2016-01-01

    Nanoporous anodic aluminum oxide was formed in sulfuric acid with addition of indigo carmine. During anodizing, the organic dye was incorporated into the porous oxide walls. X-ray photoelectron spectroscopy revealed the presence of nitrogen and sulfur in the anodic aluminum oxide. Two types of incorporated sulfur were found: belonging to the sulfate anions SO{sub 4}{sup 2−} of the electrolyte and belonging to the C-SO{sub 3}{sup −} side groups of the indigo carmine. Raman spectroscopy confirmed the incorporation and showed that the inorganic–organic hybrid material inherited optical properties from the indigo carmine. Typical modes from pyrrolidone rings, unique for indigo carmine in the investigated system (650 and 1585 cm{sup −1}), were found to be the strongest for the greatest anodizing voltages used. Despite the indigo carmine incorporation, the morphology of the oxide is still nanoporous and its geometry is still tuned by the voltage applied during aluminum anodization. This work presents an inexpensive and facile approach to doping an inorganic oxide material with organic compounds. - Highlights: • Nanoporous anodic alumina was formed in electrolyte with indigo carmine. • XPS confirmed the presence of N and S in anodic alumina. • Raman spectroscopy revealed indigo carmine bands in anodic alumina. • The higher the voltage, the more indigo carmine was incorporated.

  12. FIB-SEM investigation of trapped intermetallic particles in anodic oxide films on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Dunin-Borkowski, Rafal E.

    2011-01-01

    -containing intermetallic particles incorporated into the anodic oxide films on industrially pure aluminium (AA1050, 99.5 per cent) has been investigated. AA1050 aluminium was anodized in a 100?ml/l sulphuric acid bath with an applied voltage of 14?V at 20°C ±2°C for 10 or 120?min. The anodic film subsequently was analyzed...

  13. Silicon oxide based high capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  14. Fabrication and Characterization of Graded Anodes for Anode-Supported Solid Oxide Fuel Cells by Tape Casting and Lamination

    DEFF Research Database (Denmark)

    Beltran-Lopez, J.F.; Laguna-Bercero, M.A.; Gurauskis, Jonas

    2014-01-01

    of tapes at room temperature without using plasticizers. This is made by the combination of two different binders with varying Tg (glass transition temperature) which resulted in plastic deformation at room temperature. Those results indicate that the proposed process is a cost-effective method......Graded anodes for anode-supported solid oxide fuel cells (SOFCs) are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting...

  15. Solvent effects on the morphology and performance of the anode substrates for solid oxide fuel cells

    Science.gov (United States)

    Liu, Tong; Ren, Cong; Zhang, Yanxiang; Wang, Yao; Lei, Libin; Chen, Fanglin

    2017-09-01

    Solvents effects on the microstructure of anode substrates as well as the electrochemical performance of the respective cells are systematically evaluated. The solubility parameters are used to interpret the relationship between the rheological properties of phase inversion slurries and pore formation mechanism of the anode substrates. When N-methyl-2-pyrrolidone (NMP) is chosen as the solvent, a dual-layered anode substrates with hierarchically oriented pores is achieved, while a sponge-like homogeneous anode substrate is obtained using dimethyl sulfoxide (DMSO) as the solvent, indicating that solvent is a key factor to affect the anode substrate microstructure. Two-dimensional and three-dimensional microstructures of the anode substrates prepared using NMP are analyzed by scanning electron microscopy and X-ray microscopy, respectively. Solid oxide fuel cells (SOFCs) with different microstructured anode substrates are prepared, and the maximum power density is significantly enhanced from 320.3 to 719.2 mWcm-2 by varying the anode substrate from homogeneous sponge-like microstructure to dual-layered microstructure, revealing that the finger-like macro-voids layer can facilitate H2-H2O mass diffusion, while the thin sponge-like pores layer can serve as anode functional layer and provide sufficient active reaction sites for H2 oxidation. This study demonstrates that NMP is a promising solvent to fabricate hierarchically oriented anode for high-performance SOFCs application.

  16. Morphology of TiO2 Nanotube Arrays Prepared by Anodic Oxidation%阳极氧化法制备二氧化钛纳米管阵列的形貌

    Institute of Scientific and Technical Information of China (English)

    谭志谋; 王慧洁; 杨杭生; 张孝彬

    2013-01-01

    Highly ordered titanium oxide nanotube arrays were fabricated by titanium anodic oxidation in a glycol solution containing 5% ammonium fluoride.Influences of anodizing voltage and electrode distance on morphology of the nanotube arrays were investigated.By fine tuning the anodizing voltage,the inner diameter of the titanium oxide nanotube arrays ranged between 20~145 nm.Amost perfect and highly ordered titanium oxide nanopore arrays could also be prepared by properly controlling the distance between two electrodes.Moreover,the morphology variation of the highly ordered titanium oxide nanotube/nanopore arrays was explained by the current density distribution inside the titanium oxide film simulated by finite element analysis.%采用阳极氧化法,以NH4 F-乙二醇-水溶液为电解质,在钛片上制备了TiO2纳米管阵列,并研究了电解电压和电极距离对TiO2多孔薄膜形貌的影响.结果表明,通过优化电解电压,可以调控二氧化钛纳米管阵列的内径在20~145nm之间;通过调节两电极间的间距,在金属钛片上制备了完整的二氧化钛纳米孔阵列.并采用有限元模拟二氧化钛层中的电流密度分布,探讨了二氧化钛纳米管阵列和纳米孔阵列的形成.

  17. Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

    Science.gov (United States)

    Shvets, Petr; Maksimova, Ksenia; Demin, Maxim; Dikaya, Olga; Goikhman, Alexander

    2017-05-01

    The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

  18. Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

    Energy Technology Data Exchange (ETDEWEB)

    Shvets, Petr, E-mail: pshvets@innopark.kantiana.ru; Maksimova, Ksenia; Demin, Maxim; Dikaya, Olga; Goikhman, Alexander

    2017-05-15

    The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

  19. Biocompatibility tests performed on nanoporous aluminum oxide coated with polyethyleneglycol and titanium dioxide

    OpenAIRE

    2011-01-01

    Anodized aluminium oxide may be chemically treated to yield a uniform self-organized distribution of pores with a specific pore diameter. The thickness of in-house anodized alumina and its pore size can be modified by changing the electrolyte, the temperature of the electrolyte, the time of anodization and the potential over the anodized plates.  In this thesis, a method for anodized aluminium oxide (AAO) was optimized for creating custom-made porous alumina membranes and coating them with Ti...

  20. Nickel/Yttria-stabilised zirconia cermet anodes for solid oxide fuel cells

    NARCIS (Netherlands)

    Primdahl, Søren

    1999-01-01

    This thesis deals with the porous Ni/yttria-stabilized zirconia (YSZ) cermet anode on a YSZ electrolyte for solid oxide fuel cells (SOFC). Such anodes are predominantly operated in moist hydrogen at 700°C to 1000°C, and the most important technological parameters are the polarization resistance and

  1. Friction stir processed Al - Metal oxide surface composites: Anodization and optical appearance

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Canulescu, Stela

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate metal oxide (TiO2, Y2O3 and CeO2) particles into the surface of an Aluminium alloy. The surface composites were then anodized in a sulphuric acid electrolyte. The effect of anodizing parameters on the resulting optical...

  2. Ni modified ceramic anodes for direct-methane solid oxide fuel cells

    Science.gov (United States)

    Xiao, Guoliang; Chen, Fanglin

    2016-01-19

    In accordance with certain embodiments of the present disclosure, a method for fabricating a solid oxide fuel cell is described. The method includes synthesizing a composition having a perovskite present therein. The method further includes applying the composition on an electrolyte support to form an anode and applying Ni to the composition on the anode.

  3. Galvanic detection of sulfur dioxide in ambient air at trace levels by anodic oxidation

    NARCIS (Netherlands)

    Lindqvist, F.

    1978-01-01

    A continuous method for the measurement of SO2 in ambient air at trace levels is described. The principle of detection is based on the anodic oxidation of SO2 in a galvanic cell. A differential measuring technique with a cell with two anodes and one cathode is used; background and noise current are

  4. Novel Combination of Efficient Perovskite Solar Cells with Low Temperature Processed Compact TiO2 Layer via Anodic Oxidation.

    Science.gov (United States)

    Du, Yangyang; Cai, Hongkun; Wen, Hongbin; Wu, Yuxiang; Huang, Like; Ni, Jian; Li, Juan; Zhang, Jianjun

    2016-05-25

    In this work, a facile and low temperature processed anodic oxidation approach is proposed for fabricating compact and homogeneous titanium dioxide film (AO-TiO2). In order to realize morphology and thickness control of AO-TiO2, the theory concerning anodic oxidation (AO) is unveiled and the influence of relevant parameters during the process of AO such as electrolyte ingredient and oxidation voltage on AO-TiO2 formation is observed as well. Meanwhile, we demonstrate that the planar perovskite solar cells (p-PSCs) fabricated in ambient air and utilizing optimized AO-TiO2 as electron transport layer (ETL) can deliver repeatable power conversion efficiency (PCE) over 13%, which possess superior open-circuit voltage (Voc) and higher fill factor (FF) compared to its counterpart utilizing conventional high temperature processed compact TiO2 (c-TiO2) as ETL. Through a further comparative study, it is indicated that the improvement of device performance should be attributed to more effective electron collection from perovskite layer to AO-TiO2 and the decrease of device series resistance. Furthermore, hysteresis effect about current density-voltage (J-V) curves in TiO2-based p-PSCs is also unveiled.

  5. Synthesis and characterization of atomic layer deposited titanium nitride thin films on lithium titanate spinel powder as a lithium-ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Mark Q.; Wheeler, M. Clayton [Department of Chemical and Biological Engineering, University of Maine, 5737 Jenness Hall, Orono, ME 04469 (United States); Trebukhova, Svetlana A.; Ravdel, Boris; DiCarlo, Joseph [Yardney Technical Products/Lithion Inc., Pawcatuck, CT 06379 (United States); Tripp, Carl P. [Laboratory for Surface Science and Technology (LASST), 5708 ESRB-Barrows, Orono, ME 04469 (United States); Department of Chemistry, University of Maine, Orono, ME 04469 (United States); DeSisto, William J. [Department of Chemical and Biological Engineering, University of Maine, 5737 Jenness Hall, Orono, ME 04469 (United States); Laboratory for Surface Science and Technology (LASST), 5708 ESRB-Barrows, Orono, ME 04469 (United States)

    2007-02-25

    Lithium titanate spinel (Li{sub 4}Ti{sub 5}O{sub 12}, or LTS) is receiving consideration as a nanopowder anode material for use in lithium-ion batteries. LTS has more positive working potential than traditional graphite anodes, and it does not react with electrolyte components. However, the main drawback of LTS powder is its poor interparticle electronic conductance that reduces the high-rate ability of the electrode. To improve this we have coated the surface of the LTS powder with a titanium nitride layer by atomic layer deposition (ALD). In situ infrared spectroscopy studies were conducted to confirm the attachment of the titanium precursor. The nitrogen content of films was measured by total nitrogen content testing. Transmission electron microscopy (TEM) micrographs confirmed the formation of a thin titanium nitride film around LTS particles by ALD. Finally, lithium cells with electrodes made of original and modified LTS nanopowders were assembled and tested. (author)

  6. Chemical vapor deposition coatings for oxidation protection of titanium alloys

    Science.gov (United States)

    Cunnington, G. R.; Robinson, J. C.; Clark, R. K.

    1991-01-01

    Results of an experimental investigation of the oxidation protection afforded to Ti-14Al-21Nb and Ti-14Al-23Nb-2V titanium aluminides and Ti-17Mo-3Al-3Nb titanium alloy by aluminum-boron-silicon and boron-silicon coatings are presented. These coatings are applied by a combination of physical vapor deposition (PVD) and chemical vapor deposition (CVD) processes. The former is for the application of aluminum, and the latter is for codeposition of boron and silicon. Coating thickness is in the range of 2 to 7 microns, and coating weights are 0.6 to 2.0 mg/sq cm. Oxidation testing was performed in air at temperatures to 1255 K in both static and hypersonic flow environments. The degree of oxidation protection provided by the coatings is determined from weight change measurements made during the testing and post test compositional analyses. Temperature-dependent total normal emittance data are also presented for four coating/substrate combinations. Both types of coatings provided excellent oxidation protection for the exposure conditions of this investigation. Total normal emittances were greater than 0.80 in all cases.

  7. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  8. Use of Molten Salt Fluxes and Cathodic Protection for Preventing the Oxidation of Titanium at Elevated Temperatures

    Science.gov (United States)

    Schwandt, Carsten; Fray, Derek J.

    2014-12-01

    The current study demonstrates that it is possible to protect both solid and liquid titanium and titanium alloys from attack from air by cathodically polarizing the titanium component using an electro-active high-temperature molten salt flux and a moderate polarization potential. The electrolytic cell used comprises a cathode of either solid titanium or liquid titanium alloy, an electrolyte based on molten calcium chloride or fluoride salt, and an anode consisting of an inert oxygen-evolving material such as iridium metal. The new approach renders possible the processing of titanium at elevated temperatures in the presence of oxygen-containing atmospheres.

  9. Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

    Science.gov (United States)

    Nourmohammadi, Abolghasem; Asadabadi, Saeid Jalali; Yousefi, Mohammad Hasan; Ghasemzadeh, Majid

    2012-12-01

    The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

  10. Microstructural characterization and field emission properties of tungsten oxide and titanium-oxide-doped tungsten oxide nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chia-Hsiang [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Su, Cherng-Yuh, E-mail: cysu@ntut.edu.tw [Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Lin, Yan-Fu [Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan (China)

    2015-03-01

    Tungsten oxide and titanium-oxide-doped tungsten oxide nanowires were synthesized by using the DC magnetron sputtering and infrared furnace annealing processes. Scanning election microscopy (SEM) and transmission electron microscopy (TEM) were utilized to evaluate the topography and sizes. X-ray diffraction (XRD), grazing incidence X-ray diffraction (GI-XRD), and high-resolution transmission electron microscopy (HRTEM) were used to analyze the composition and structure. From the results of HRTEM, it was discovered that the prepared nanowires have a monoclinic single-crystal phase of W{sub 18}O{sub 49} with lattice growth along the (010) lattice plane, and the lattice spacing is 0.378 nm, which agrees with XRD and GI-XRD results. The prepared tungsten oxide and titanium-oxide-doped tungsten oxide nanowires have turn-on voltage of 3.06 V/μm and 1.46 V/μm respectively. They also possess superior field enhancement factors of 5103 and 10667 respectively. Their behavior thus follows the Fowler-Nordheim expression for tunneling. - Highlights: • A simple method to prepare tungsten oxide nanowires by annealing tungsten film. • High aspect ratio of the 1D titanium-oxide-doped tungsten oxide nanowires. • High field enhancement factor of titanium-oxide-doped tungsten oxide nanowires.

  11. Anodic Oxidation of Carbon Steel at High Current Densities and Investigation of Its Corrosion Behavior

    Science.gov (United States)

    Fattah-Alhosseini, Arash; Khan, Hamid Yazdani

    2017-02-01

    This work aims at studying the influence of high current densities on the anodization of carbon steel. Anodic protective coatings were prepared on carbon steel at current densities of 100, 125, and 150 A/dm2 followed by a final heat treatment. Coatings microstructures and morphologies were analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the uncoated carbon steel substrate and the anodic coatings were evaluated in 3.5 wt pct NaCl solution through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that the anodic oxide coatings which were prepared at higher current densities had thicker coatings as a result of a higher anodic forming voltage. Therefore, the anodized coatings showed better anti-corrosion properties compared to those obtained at lower current densities and the base metal.

  12. Narrow titanium oxide nanowires induced by femtosecond laser pulses on a titanium surface

    Science.gov (United States)

    Li, Hui; Li, Xian-Feng; Zhang, Cheng-Yun; Tie, Shao-Long; Lan, Sheng

    2017-02-01

    The evolution of the nanostructure induced on a titanium (Ti) surface with increasing irradiation pulse number by using a 400-nm femtosecond laser was examined by using scanning electron microscopy. High spatial frequency periodic structures of TiO2 parallel to the laser polarization were initially observed because of the laser-induced oxidation of the Ti surface and the larger efficacy factor of TiO2 in this direction. Periodically aligned TiO2 nanowires with featured width as small as 20 nm were obtained. With increasing pulse number, however, low spatial frequency periodic structures of Ti perpendicular to the laser polarization became dominant because Ti possesses a larger efficacy factor in this direction. The competition between the high- and low-spatial frequency periodic structures is in good agreement with the prediction of the efficacy factor theory and it should also be observed in the femtosecond laser ablation of other metals which are easily oxidized in air.

  13. Synthesis of silver nanotubes by electroless deposition in porous anodic aluminium oxide templates.

    Science.gov (United States)

    Zhang, Shu-Hong; Xie, Zhao-Xiong; Jiang, Zhi-Yuan; Xu, Xin; Xiang, Juan; Huang, Rong-Bin; Zheng, Lan-Sun

    2004-05-07

    An electroless deposition method has been employed for the synthesis of silver nanotubes using porous anodic aluminium oxide as templates, by which high-yield silver nanotubes with length over ten microns have been synthesized.

  14. Growth of porous type anodic oxide films at micro-areas on aluminum exposed by laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Tatsuya [Graduate School of Engineering, Hokkaido University, N13-W8, Kita-Ku, Sapporo 060-8628 (Japan)], E-mail: kiku@eng.hokudai.ac.jp; Sakairi, Masatoshi [Graduate School of Engineering, Hokkaido University, N13-W8, Kita-Ku, Sapporo 060-8628 (Japan); Takahashi, Hideaki [Asahikawa National College of Technology, Syunkohdai, 2-2, 1-6, Asahikawa 071-8142 (Japan)

    2009-11-30

    Aluminum covered with pore-sealed anodic oxide films was irradiated with a pulsed Nd-YAG laser to remove the oxide film at micro-areas. The specimen was re-anodized for long periods to examine the growth of porous anodic oxide films at the area where substrate had been exposed by measuring current variations and morphological changes in the oxide during the re-anodizing. The chemical dissolution resistance of the pore-sealed anodic oxide films in an oxalic acid solution was also examined by measuring time-variations in rest potentials during immersion. The resistance to chemical dissolution of the oxide film became higher with increasing pore-sealing time and showed higher values at lower solution temperatures. During potentiostatic re-anodizing at five 35-{mu}m wide and 4-mm long lines for 72 h after the film was removed the measured current was found to increase linearly with time. Semicircular columnar-shaped porous type anodic oxide was found to form during the re-anodizing at the laser-irradiated area, and was found to grow radially, thus resulting in an increase in the diameter. After long re-anodizing, the central and top parts of the oxide protruded along the longitudinal direction of the laser-irradiated area. The volume expansion during re-anodizing resulted in the formation of cracks, parallel to the lines, in the oxide film formed during the first anodizing.

  15. Nanoporous Pirani sensor based on anodic aluminum oxide

    Science.gov (United States)

    Jeon, Gwang-Jae; Kim, Woo Young; Shim, Hyun Bin; Lee, Hee Chul

    2016-09-01

    A nanoporous Pirani sensor based on anodic aluminum oxide (AAO) is proposed, and the quantitative relationship between the performance of the sensor and the porosity of the AAO membrane is characterized with a theoretical model. The proposed Pirani sensor is composed of a metallic resistor on a suspended nanoporous membrane, which simultaneously serves as the sensing area and the supporting structure. The AAO membrane has numerous vertically-tufted nanopores, resulting in a lower measurable pressure limit due to both the increased effective sensing area and the decreased effective thermal loss through the supporting structure. Additionally, the suspended AAO membrane structure, with its outer periphery anchored to the substrate, known as a closed-type design, is demonstrated using nanopores of AAO as an etch hole without a bulk micromachining process used on the substrate. In a CMOS-compatible process, a 200 μm × 200 μm nanoporous Pirani sensor with porosity of 25% was capable of measuring the pressure from 0.1 mTorr to 760 Torr. With adjustment of the porosity of the AAO, the measurable range could be extended toward lower pressures of more than one decade compared to a non-porous membrane with an identical footprint.

  16. CNTs tuning and vertical alignment in anodic aluminium oxide membrane

    Institute of Scientific and Technical Information of China (English)

    Maria Sarno; Diana Sannino; Caterina Leone; Paolo Ciambelli

    2012-01-01

    Anodic aluminium oxide (AAOM) membranes were used for template growth of carbon nanotubes (CNT) inside their pores by chemical vapour deposition (CVD) of different hydrocarbons,in the absence of transition metal catalyst.A composite material,containing one nanotube for each channel,having the same length as the membrane thickness and the external diameter close to the diameter of the membrane holes,was obtained.Yield,selectivity,and quality of CNTs in terms of diameter (up to very thin CNT),carbon order,length,arrangement (i.e.number of tubes for each channel),purity,that are critical requisites for several applications were optimized by investigating the effect of changing the hydrocarbon feedstock gas,also in the presence of hydrogen.The samples produced using methane as a feedstock have a well ordered structure.The role of the alumina channels surface during the CNT growth has been investigated and its catalytic activity has been proved for the first time.

  17. Facile fabrication of nanofluidic diode membranes using anodic aluminium oxide.

    Science.gov (United States)

    Wu, Songmei; Wildhaber, Fabien; Vazquez-Mena, Oscar; Bertsch, Arnaud; Brugger, Juergen; Renaud, Philippe

    2012-09-21

    Active control of ion transport plays important roles in chemical and biological analytical processes. Nanofluidic systems hold the promise for such control through electrostatic interaction between ions and channel surfaces. Most existing experiments rely on planar geometry where the nanochannels are generally very long and shallow with large aspect ratios. Based on this configuration the concepts of nanofluidic gating and rectification have been successfully demonstrated. However, device minimization and throughput scaling remain significant challenges. We report here an innovative and facile realization of hetero-structured Al(2)O(3)/SiO(2) (Si) nanopore array membranes by using pattern transfer of self-organized nanopore structures of anodic aluminum oxide (AAO). Thanks to the opposite surface charge states of Al(2)O(3) (positive) and SiO(2) (negative), the membrane exhibits clear rectification of ion current in electrolyte solutions with very low aspect ratios compared to previous approaches. Our hetero-structured nanopore arrays provide a valuable platform for high throughput applications such as molecular separation, chemical processors and energy conversion.

  18. Fabrication and characterization of conductive anodic aluminum oxide substrates

    Science.gov (United States)

    Altuntas, Sevde; Buyukserin, Fatih

    2014-11-01

    Biomaterials that allow the utilization of electrical, chemical and topographic cues for improved neuron-material interaction and neural regeneration hold great promise for nerve tissue engineering applications. The nature of anodic aluminum oxide (AAO) membranes intrinsically provides delicate control over topographic and chemical cues for enhanced cell interaction; however their use in nerve regeneration is still very limited. Herein, we report the fabrication and characterization of conductive AAO (CAAO) surfaces for the ultimate goal of integrating electrical cues for improved nerve tissue behavior on the nanoporous substrate material. Parafilm was used as a protecting polymer film, for the first time, in order to obtain large area (50 cm2) free-standing AAO membranes. Carbon (C) was then deposited on the AAO surface via sputtering. Morphological characterization of the CAAO surfaces revealed that the pores remain open after the deposition process. The presence of C on the material surface and inside the nanopores was confirmed by XPS and EDX studies. Furthermore, I-V curves of the surface were used to extract surface resistance values and conductive AFM demonstrated that current signals can only be achieved where conductive C layer is present. Finally, novel nanoporous C films with controllable pore diameters and one dimensional (1-D) C nanostructures were obtained by the dissolution of the template AAO substrate.

  19. Highly ordered zinc oxide nanotubules synthesized within the anodic aluminum oxide template

    Science.gov (United States)

    Wang, Z.; Li, H. L.

    Zinc oxide (ZnO) nanotubules were prepared by sol-gel synthesis within the pores of an anodic aluminum oxide (AAO) template. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and X-ray Diffraction (XRD) were used to investigate the morphology and crystalloid structures of the ZnO nanotubules. The results indicate that polycrystalline ZnO nanotubules are very uniformly assembled and parallel to each other in the membrane pores of the AAO template.

  20. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

    Energy Technology Data Exchange (ETDEWEB)

    Beltrán-Partida, Ernesto [Department of Biomaterials, Dental Materials and Tissue Engineering, Faculty of Dentistry Mexicali, Autonomous University of Baja California, Av. Zotoluca and Chinampas St., 21040 Mexicali, Baja California (Mexico); Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Benjamín, E-mail: benval@uabc.edu.mx [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Escamilla, Alan; Curiel, Mario [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Ernesto [Ixchel Medical Centre, Av. Bravo y Obregón, 21000 Mexicali, Baja California (Mexico); Nedev, Nicola [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Bastidas, Jose M. [National Centre for Metallurgical Research, CSIC, Av. Gregorio del Amo 8, 28040 Madrid (Spain)

    2016-03-01

    Amorphous titanium dioxide (TiO{sub 2}) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO{sub 2} nanotubes.

  1. Microstructural characterization of oxide film formed on NiTi by anodization in acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, F.T. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)]. E-mail: apaftche@polyu.edu.hk; Shi, P. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Department of Materials and Chemical Engineering, Liaoning Institute of Technology, Jinzhou, Liaoning (China); Pang, G.K.H. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Wong, M.H. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Man, H.C. [Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2007-07-12

    NiTi was galvanostatically anodized in acetic acid aiming at forming an anodic film for improving corrosion resistance. While the corrosion behavior of anodized NiTi in Hanks' solution was reported elsewhere [P. Shi, F.T. Cheng, H.C. Man, Mater. Lett., submitted for publication], the present work reports the microstructural characterization of the anodic film formed. Bright-field image of the sample cross-section captured by transmission electron microscopy (TEM) revealed an oxide film of about 20 nm thick, which was smooth and free of defects. The surface roughness R {sub a} of the film, determined by atomic force microscopy (AFM), was about 1.45 nm. Analysis by X-ray photoelectron spectroscopy (XPS) along the depth of the anodic film indicated that the oxidation state of Ti varied from +4 (corresponding to TiO{sub 2}) at the surface to lower oxidation states (corresponding to Ti suboxides) beneath. A small amount of Ni in the metallic and oxidized states was also present. The Ni/Ti atomic ratio was about 0.04 at the surface of the anodic film, which was much lower than the corresponding value of 0.30 for the mechanically polished samples. Selected-area diffraction (SAD) patterns and high-resolution TEM image of the anodic film showed that the film was amorphous.

  2. Stabilisation of composite LSFCO-CGO based anodes for methane oxidation in solid oxide fuel cells

    Science.gov (United States)

    Sin, A.; Kopnin, E.; Dubitsky, Y.; Zaopo, A.; Aricò, A. S.; Gullo, L. R.; Rosa, D. La; Antonucci, V.

    A La 0.6Sr 0.4Fe 0.8Co 0.2O 3-Ce 0.8Gd 0.2O 1.9 (LSFCO-CGO) composite anode material was investigated for the direct electrochemical oxidation of methane in intermediate temperature solid oxide fuel cells (IT-SOFCs). A maximum power density of 0.17 W cm -2 at 800 °C was obtained with a methane-fed ceria electrolyte-supported SOFC. A progressive increase of performance was recorded during 140 h operation with dry methane. The anode did not show any structure degradation after the electrochemical testing. Furthermore, no formation of carbon deposits was detected by electron microscopy and elemental analysis. Alternatively, this perovskite material showed significant chemical and structural modifications after high temperature treatment in a dry methane stream in a packed-bed reactor. It is derived that the continuous supply of mobile oxygen anions from the electrolyte to the LSFCO anode, promoted by the mixed conductivity of CGO electrolyte at 800 °C, stabilises the perovskite structure near the surface under SOFC operation and open circuit conditions.

  3. Performance of alternative oxide anodes for the electrochemical oxidation of hydrogen and methane in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Tu, H.; Apfel, H.; Stimming, U. [Department of Physics E19, Technical University of Munich, James-Franck-Strasse 1, D-85748 Garching (Germany)

    2006-07-15

    The electrode performances of the alternative oxides: La{sub 0.05}Ca{sub 0.95}Cr{sub 0.05}Ti{sub 0.95}O{sub 3-{delta}}-8YSZ and Ce{sub 0.8}TM{sub 0.2}O{sub 2-{delta}}(TM=Mn, Co) for the direct electrochemical oxidation of methane are investigated to assess their potential as anode materials for efficient methane conversion in a SOFC. The electrochemical oxidation of hydrogen was also studied, for comparison. The oxides are characterised electrochemically with impedance spectroscopy in the frequency range from 10 mHz to 1MHz, using a three-electrode geometry. They are compared to a standard Ni/8YSZ anode for the electrochemical oxidation of hydrogen. It is found that La{sub 0.05}Ca{sub 0.95}Cr{sub 0.05}Ti{sub 0.95}O{sub 3-{delta}}-8YSZ demonstrates a poor electrochemical activity in both hydrogen and methane. However, the electrochemical activity of Ce{sub 0.8}Mn{sub 0.2}O{sub 2-{delta}} is promising, but the electronic conductivity needs to be increased, e.g., by adding a conducting oxide, before it can be used as an anode material in a SOFC. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  4. Nanostructured Titanium Oxide Film- And Membrane-Based Photocatalysis For Water Treatment

    Science.gov (United States)

    Titanium Oxide (TiO2) photocatalysis, one of the ultraviolet (UV)-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness ...

  5. Nanostructured Titanium Oxide Film- And Membrane-Based Photocatalysis For Water Treatment

    Science.gov (United States)

    Titanium Oxide (TiO2) photocatalysis, one of the ultraviolet (UV)-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness ...

  6. Evolution of Anode Porosity under Air Oxidation: The Unveiling of the Active Pore Size

    Directory of Open Access Journals (Sweden)

    Francois Chevarin

    2017-03-01

    Full Text Available The carbon anode, used in aluminum electrolysis (Hall–Héroult process, is over-consumed by air oxidation and carboxy-reaction (with CO2. Several anode features may affect this over-consumption, such as impurity content, graphitization level and anode porosity features (e.g., porosity volume fraction or pore size distribution. The two first parameters are basically related to the quality of raw materials and coke calcination conditions. Anode porosity is, however, greatly affected by anode manufacturing conditions, and is possible to be modified, to some extent, by adjusting the anode recipe and the processing parameters. This work aims to investigate the effect of anode porosity on its air reactivity. Baked anode samples were prepared in laboratory scale and then crushed into powder form (−4760 + 4000 µm. The recipe for anode preparation was similar to a typical industrial recipe, except that in the lab scale no butt particles were used in the recipe. Anode particles were then gasified at six different conversion levels (0, 5, 15, 25, 35 and 50 wt % under air at 525 °C. The porosity was characterized in several pore size ranges, measured by nitrogen adsorption and mercury intrusion (0.0014–0.020, 0.002–0.025, 0.025–0.100, 0.1–40.0 and superior at 40 µm. The volume variation of each pore range, as a function of carbon conversion, was assessed and used to determine the size of the most active pores for air oxidation. The most active pore size was found to be the pores inferior at 40 µm before 15 wt % of gasification and pores superior at 40 µm between 15 and 50 wt % of carbon conversion. Limitation of pore size range could be used as an additional guideline, along with other targets such as high homogeneity and density, to set the optimum anode manufacturing parameters.

  7. Effect of electrolysis voltage on electrochemical reduction of titanium oxide to titanium in molten calcium chloride

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The electrochemical reduction of solid TiO2 directly to solid metal is a ptomising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti2O were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.

  8. Structure and photoelectrochemical effeciency of oxidized titanium electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Antonucci, V. (Istituto C.N.R. di Ricerche sui Metodi e Processi Chimici per la Trasformazione e l' Accumulo dell' Energia, Messina, Italy); Giordano, N.; Bart, J.C.J.

    1982-01-01

    Pure titanium laminae were oxidized in air between 300 and 1300/sup 0/C and used as electrodes in the photodecomposition of water. The maximum photoelectrochemical conversion was found for flame-oxidized (1300/sup 0/C) samples. Although the efficiency shows a parallelism with the presence of the metallic interstitial compounds TiO/sub 0 + x/(x<0.33) and Ti/sub 2/O/sub 1-y/(0.33>y>0) at the metal-semiconductor interface, the thickness of the suboxide layer and that of the external rutile scale, it is argued that other factors (optimal suboxide-rutile distribution, overall layer thickness, layer perfection, non-stoichiometry of TiO/sub 2/, isoelectric point of solids (IEPS), etc.) may be more important in the process.

  9. Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation

    Directory of Open Access Journals (Sweden)

    Wennerberg Ann

    2011-03-01

    Full Text Available Abstract Background The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown. Methods We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy. Results Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm. Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth. Conclusions Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm

  10. Facile synthesis of reduced graphene oxide-porous silicon composite as superior anode material for lithium-ion battery anodes

    Science.gov (United States)

    Jiao, Lian-Sheng; Liu, Jin-Yu; Li, Hong-Yan; Wu, Tong-Shun; Li, Fenghua; Wang, Hao-Yu; Niu, Li

    2016-05-01

    We report a new method for synthesizing reduced graphene oxide (rGO)-porous silicon composite for lithium-ion battery anodes. Rice husks were used as a as a raw material source for the synthesis of porous Si through magnesiothermic reduction process. The as-obtained composite exhibits good rate and cycling performance taking advantage of the porous structure of silicon inheriting from rice husks and the outstanding characteristic of graphene. A considerably high delithiation capacity of 907 mA h g-1 can be retained even at a rate of 16 A g-1. A discharge capacity of 830 mA h g-1 at a current density of 1 A g-1 was delivered after 200 cycles. This may contribute to the further advancement of Si-based composite anode design.

  11. Synthesis and Electrochemical Performance of a Lithium Titanium Phosphate Anode for Aqueous Lithium-Ion Batteries

    KAUST Repository

    Wessells, Colin

    2011-01-01

    Lithium-ion batteries that use aqueous electrolytes offer safety and cost advantages when compared to today\\'s commercial cells that use organic electrolytes. The equilibrium reaction potential of lithium titanium phosphate is -0.5 V with respect to the standard hydrogen electrode, which makes this material attractive for use as a negative electrode in aqueous electrolytes. This material was synthesized using a Pechini type method. Galvanostatic cycling of the resulting lithium titanium phosphate showed an initial discharge capacity of 115 mAh/g and quite good capacity retention during cycling, 84% after 100 cycles, and 70% after 160 cycles at a 1 C cycling rate in an organic electrolyte. An initial discharge capacity of 113 mAh/g and capacity retention of 89% after 100 cycles with a coulombic efficiency above 98% was observed at a C/5 rate in pH -neutral 2 M Li2 S O4. The good cycle life and high efficiency in an aqueous electrolyte demonstrate that lithium titanium phosphate is an excellent candidate negative electrode material for use in aqueous lithium-ion batteries. © 2011 The Electrochemical Society.

  12. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongya; Dong, Guangneng, E-mail: donggn@mail.xjtu.edu.cn; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-30

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm{sup 2} for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  13. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    Science.gov (United States)

    Zhang, Dongya; Dong, Guangneng; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-01

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm2 for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  14. The Wear behavior of UHMWPE against Surface Modified CP-Titanium by Thermal Oxidation

    Directory of Open Access Journals (Sweden)

    B.T. Prayoga

    2016-12-01

    Full Text Available The effects of thermal oxidation duration on hardness, roughness, and wettability of the CP-titanium surfaces were investigated in this paper. The thermal oxidation treatment was done at 700 oC for 12-36 hours in an air atmosphere. The wear behavior of the UHMWPE sliding against treated thermal oxidation of the CP-titanium was tested by a pin-on-plate tribometer under lubrication of the solution of 75 % distilled water and 25 % bovine serum. The results showed that the layer of the oxide titanium was formed on the surface after being treated by the thermal oxidation for 12-36 hours. The oxide titanium layer was dominated by rutile form of TiO2, that offers an improvement of hardness and wettability of the CP-titanium surfaces. The average wear factor of the UHMWPE reduced significantly when the sliding against of the CP-titanium was modified by the thermal oxidation, and the lowest average wear factor was reached when the sliding against the 12 hour oxidized CP-titanium counterfaces.

  15. An Indium-Free Anode for Large-Area Flexible OLEDs: Defect-Free Transparent Conductive Zinc Tin Oxide

    NARCIS (Netherlands)

    Morales-Masis, M.; Dauzou, F.; Jeangros, Q.; Dabirian, A.; Lifka, H.; Gierth, R.; Ruske, M.; Moet, D.; Hessler-Wyser, A.; Ballif, C.

    2016-01-01

    Flexible large-area organic light-emitting diodes (OLEDs) require highly conductive and transparent anodes for efficient and uniform light emission. Tin-doped indium oxide (ITO) is the standard anode in industry. However, due to the scarcity of indium, alternative anodes that eliminate its use are h

  16. Impact of nanostructured anode on low-temperature performance of thin-film-based anode-supported solid oxide fuel cells

    Science.gov (United States)

    Park, Jung Hoon; Han, Seung Min; Yoon, Kyung Joong; Kim, Hyoungchul; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won

    2016-05-01

    The impact of a nanostructured Ni-yttria-stabilized zirconia (Ni-YSZ) anode on low-temperature solid oxide fuel cell (LT-SOFC) performance is investigated. By modifying processing techniques for the anode support, anode-supported SOFCs based on thin-film (∼1 μm) electrolytes (TF-SOFCs) with and without the nanostructured Ni-YSZ (grain size ∼100 nm) anode are fabricated and a direct comparison of the TF-SOFCs to reveal the role of the nanostructured anode at low temperature is made. The cell performance of the nanostructured Ni-YSZ anode significantly increases as compared to that of the cell without it, especially at low temperatures (500 °C). The electrochemical analyses confirm that increasing the triple-phase boundary (TPB) density near the electrolyte and anode interface by the particle-size reduction of the anode increases the number of sites available for charge transfer. Thus, the nanostructured anode not only secures the structural integrity of the thin-film components over it, it is also essential for lowering the operating temperature of the TF-SOFC. Although it is widely considered that the cathode is the main factor that determines the performance of LT-SOFCs, this study directly proves that anode performance also significantly affects the low-temperature performance.

  17. Effects of Complex Structured Anodic Oxide Dielectric Layer Grown in Pore Matrix for Aluminum Capacitor.

    Science.gov (United States)

    Shin, Jin-Ha; Yun, Sook Young; Lee, Chang Hyoung; Park, Hwa-Sun; Suh, Su-Jeong

    2015-11-01

    Anodization of aluminum is generally divided up into two types of anodic aluminum oxide structures depending on electrolyte type. In this study, an anodization process was carried out in two steps to obtain high dielectric strength and break down voltage. In the first step, evaporated high purity Al on Si wafer was anodized in oxalic acidic aqueous solution at various times at a constant temperature of 5 degrees C. In the second step, citric acidic aqueous solution was used to obtain a thickly grown sub-barrier layer. During the second anodization process, the anodizing potential of various ranges was applied at room temperature. An increased thickness of the sub-barrier layer in the porous matrix was obtained according to the increment of the applied anodizing potential. The microstructures and the growth of the sub-barrier layer were then observed with an increasing anodizing potential of 40 to 300 V by using a scanning electron microscope (SEM). An impedance analyzer was used to observe the change of electrical properties, including the capacitance, dissipation factor, impedance, and equivalent series resistance (ESR) depending on the thickness increase of the sub-barrier layer. In addition, the breakdown voltage was measured. The results revealed that dielectric strength was improved with the increase of sub-barrier layer thickness.

  18. The simulation of the temperature effects on the microhardness of anodic alumina oxide layers

    Directory of Open Access Journals (Sweden)

    M. Gombár

    2014-01-01

    Full Text Available In order to improve the mechanical properties of the layer deposited by anodic oxidation of aluminum on the material EN AW-1050 H24, in the contribution was investigated the microhardness of the deposited layer as a function of the physic-chemical factors affecting in the process of anodic oxidation at the constant anodic current density J = 3 A.dm-2 in electrolyte formed by sulfuric acid and oxalic acid, with the emphasis on the influence of electrolyte temperature in the range – 1,78 °C to 45,78 °C. The model of the studied dependence was compiled based on mathematical and statistical analysis of matrix from experimental obtained data from composite rotation plan of experiment with five independent variable factors (amount of sulfuric acid in the electrolyte, the amount of oxalic acid in the electrolyte, electrolyte, anodizing time and applied voltage.

  19. Nanopatterning of Crystalline Silicon Using Anodized Aluminum Oxide Templates for Photovoltaics

    Science.gov (United States)

    Chao, Tsu-An

    A novel thin film anodized aluminum oxide templating process was developed and applied to make nanopatterns on crystalline silicon to enhance the optical properties of silicon. The thin film anodized aluminum oxide was created to improve the conventional thick aluminum templating method with the aim for potential large scale fabrication. A unique two-step anodizing method was introduced to create high quality nanopatterns and it was demonstrated that this process is superior over the original one-step approach. Optical characterization of the nanopatterned silicon showed up to 10% reduction in reflection in the short wavelength range. Scanning electron microscopy was also used to analyze the nanopatterned surface structure and it was found that interpore spacing and pore density can be tuned by changing the anodizing potential.

  20. Anode protection system for shutdown of solid oxide fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bob X; Grieves, Malcolm J; Kelly, Sean M

    2014-12-30

    An Anode Protection Systems for a SOFC system, having a Reductant Supply and safety subsystem, a SOFC anode protection subsystem, and a Post Combustion and slip stream control subsystem. The Reductant Supply and safety subsystem includes means for generating a reducing gas or vapor to prevent re-oxidation of the Ni in the anode layer during the course of shut down of the SOFC stack. The underlying ammonia or hydrogen based material used to generate a reducing gas or vapor to prevent the re-oxidation of the Ni can be in either a solid or liquid stored inside a portable container. The SOFC anode protection subsystem provides an internal pressure of 0.2 to 10 kPa to prevent air from entering into the SOFC system. The Post Combustion and slip stream control subsystem provides a catalyst converter configured to treat any residual reducing gas in the slip stream gas exiting from SOFC stack.

  1. Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Siba P. (Murrysville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA); Liu, Xinghua (Monroeville, PA)

    2002-01-01

    An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

  2. Mechanical and tribological properties of oxide layers obtained on titanium in the thermal oxidation process

    Science.gov (United States)

    Aniołek, K.; Kupka, M.; Barylski, A.; Dercz, G.

    2015-12-01

    The paper presents the results of tests concerning a modification to the surface of titanium Grade 2 in the thermal oxidation process. It describes the oxidation kinetics of the tested material in the temperature range of 600-800 °C, with a duration from 20 min to 72 h. The greatest increase in mass was found in specimens oxidised at a temperature of 800 °C. The morphology of the obtained oxide layers was determined. The particles of oxides formed were noticeably larger after oxidation at a temperature of 600 °C. Raising temperature resulted in the formation of fine compact particles in the oxide layer. A phase analysis of oxidation products showed that TiO2 in the crystallographic form of rutile and Ti3O are the prevalent types of oxide at a temperature of 600 and 700 °C. On the other hand, only rutile formed at a temperature of 800 °C. Tribological tests showed that the presence of an oxide layer on the surface of titanium significantly improved resistance to abrasive wear. It was found that volumetric wear had decreased by 48% for a specimen oxidised at a temperature of 600 °C and by more than 60% for a specimen subjected to isothermal soaking at a temperature of 700 °C.

  3. Compositional and structural evolution of the titanium dioxide formation by thermal oxidation

    Institute of Scientific and Technical Information of China (English)

    Su Wei-Feng; Gnaser Hubert; Fan Yong-Liang; Jiang Zui-Min; Le Yong-Kang

    2008-01-01

    Titanium oxide films were prepared by annealing DC magnetron sputtered titanium films in an oxygen ambi-ent. X-ray diffraction (XRD), Auger electron spectroscopy (AES) sputter profiling, MCs+-mode secondary ion mass spectrometry (MCs+-SIMS) and atomic force microscopy (AFM) were employed, respectively, for the structural, com-positional and morphological characterization of the obtained films. For temperatures below 875 K, titanium films could not be fully oxidized within one hour. Above that temperature, the completely oxidized films were found to be rutile in structure. Detailed studies on the oxidation process at 925 K were carried out for the understanding of the underlying mechanism of titanium dioxide (TiO2) formation by thermal oxidation. It was demonstrated that the formation of crystalline TiO2 could be divided into a short oxidation stage, followed by crystal forming stage. Relevance of this recognition was further discussed.

  4. The electrochemical oxidation of H{sub 2} and CO at patterned Ni anodes of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Utz, Annika

    2011-07-01

    In this work, a deeper understanding of the electrochemical oxidation at SOFC anodes was gained by the experimental characterization of patterned Ni anodes in H{sub 2}-H{sub 2}O and CO-CO{sub 2} atmosphere. By high resolution data analysis, the Line Specific Resistance attributed to charge transfer and its dependencies on gas composition, temperature and polarization voltage were identified. Furthermore, the comparison of the performance of patterned and cermet anodes was enabled using a transmission line model. (orig.)

  5. Modelling the growth process of porous aluminum oxide film during anodization

    Science.gov (United States)

    Aryslanova, E. M.; Alfimov, A. V.; Chivilikhin, S. A.

    2015-11-01

    Currently it has become important for the development of metamaterials and nanotechnology to obtain regular self-assembled structures. One such structure is porous anodic alumina film that consists of hexagonally packed cylindrical pores. In this work we consider the anodization process, our model takes into account the influence of layers of aluminum and electrolyte on the rate of growth of aluminum oxide, as well as the effect of surface diffusion. In present work we consider those effects. And as a result of our model we obtain the minimum distance between centers of alumina pores in the beginning of anodizing process.

  6. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

    2012-01-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell,...

  7. Biocatalytic anode for glucose oxidation utilizing carbon nanotubes for direct electron transfer with glucose oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Vaze, Abhay; Hussain, Nighat; Tang, Chi [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Leech, Donal [School of Chemistry, National University of Ireland, Galway (Ireland); Rusling, James [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06032 (United States); School of Chemistry, National University of Ireland, Galway (Ireland)

    2009-10-15

    Covalently linked layers of glucose oxidase, single-wall carbon nanotubes and poly-L-lysine on pyrolytic graphite resulted in a stable biofuel cell anode featuring direct electron transfer from the enzyme. Catalytic response observed upon addition of glucose was due to electrochemical oxidation of FADH{sub 2} under aerobic conditions. The electrode potential depended on glucose concentration. This system has essential attributes of an anode in a mediator-free biocatalytic fuel cell. (author)

  8. Improving Osteoblast Response In Vitro by a Nanostructured Thin Film with Titanium Carbide and Titanium Oxides Clustered around Graphitic Carbon.

    Directory of Open Access Journals (Sweden)

    Giovanni Longo

    Full Text Available Recently, we introduced a new deposition method, based on Ion Plating Plasma Assisted technology, to coat titanium implants with a thin but hard nanostructured layer composed of titanium carbide and titanium oxides, clustered around graphitic carbon. The nanostructured layer has a double effect: protects the bulk titanium against the harsh conditions of biological tissues and in the same time has a stimulating action on osteoblasts.The aim of this work is to describe the biological effects of this layer on osteoblasts cultured in vitro. We demonstrate that the nanostructured layer causes an overexpression of many early genes correlated to proteins involved in bone turnover and an increase in the number of surface receptors for α3β1 integrin, talin, paxillin. Analyses at single-cell level, by scanning electron microscopy, atomic force microscopy, and single cell force spectroscopy, show how the proliferation, adhesion and spreading of cells cultured on coated titanium samples are higher than on uncoated titanium ones. Finally, the chemistry of the layer induces a better formation of blood clots and a higher number of adhered platelets, compared to the uncoated cases, and these are useful features to improve the speed of implant osseointegration.In summary, the nanostructured TiC film, due to its physical and chemical properties, can be used to protect the implants and to improve their acceptance by the bone.

  9. Facile preparation of titanium dioxide nano-capsule arrays used as photo-anode for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Su, Penglei; Li, Hongyi, E-mail: lhy06@bjut.edu.cn; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Wu, Junshu; Zhao, Bingxin; Wang, Fei

    2015-08-30

    Graphical abstract: - Highlights: • TiO{sub 2} nanoparticles have been introduced into TiO{sub 2} nanotube using a facile liquid phase deposition method at low temperature in atmosphere. • Dye solar cells have been assembled on flexible titanium substrate. • The incident photo-electron conversion efficiency has been improved 76% compared with pure TiO{sub 2} nanotube arrays. - Abstract: To improve titanium dioxide (TiO{sub 2}) nanotube arrays’ performance on dye sensitized solar cells (DSSCs), TiO{sub 2} nano-capsule arrays (TNCP) have been designed and prepared by planting TiO{sub 2} nanoparticles into TiO{sub 2} nanotube (TNT) using a facile liquid phase deposition (LPD) route which does not require any special equipment and both improve the specific surface area and surface energy of TNT at low temperature. It has been found that TiO{sub 2} nanoparticles are homogeneously distributed along the wall of TNT and their crystal size is calculated to be 5–10 nm. The obtained TNCP's specific surface area and surface energy have been increased from 27.1 (for pure TNT) to 33.4 m{sup 2}/g and from 67.7 (for pure TNT) to 76.4 mJ/m{sup 2}, respectively. When used as photo-anodes of DSSCs, TNCP shows higher energy conversion efficiency, which is 1.7 times that of pure TNT. Therefore, the present work provides one effective strategy to better TNT's performance on DSSCs, which can be assembled on metal substrate in large scale.

  10. Molecular plasma deposition: biologically inspired nanohydroxyapatite coatings on anodized nanotubular titanium for improving osteoblast density

    Directory of Open Access Journals (Sweden)

    Balasundaram G

    2015-01-01

    Full Text Available Ganesan Balasundaram,1 Daniel M Storey,1 Thomas J Webster2,3 1Chameleon Scientific, Longmont, CO, USA; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: In order to begin to prepare a novel orthopedic implant that mimics the natural bone environment, the objective of this in vitro study was to synthesize nanocrystalline hydroxyapatite (NHA and coat it on titanium (Ti using molecular plasma deposition (MPD. NHA was synthesized through a wet chemical process followed by a hydrothermal treatment. NHA and micron sized hydroxyapatite (MHA were prepared by processing NHA coatings at 500°C and 900°C, respectively. The coatings were characterized before and after sintering using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results revealed that the post-MPD heat treatment of up to 500°C effectively restored the structural and topographical integrity of NHA. In order to determine the in vitro biological responses of the MPD-coated surfaces, the attachment and spreading of osteoblasts (bone-forming cells on the uncoated, NHA-coated, and MHA-coated anodized Ti were investigated. Most importantly, the NHA-coated substrates supported a larger number of adherent cells than the MHA-coated and uncoated substrates. The morphology of these cells was assessed by scanning electron microscopy and the observed shapes were different for each substrate type. The present results are the first reports using MPD in the framework of hydroxyapatite coatings on Ti to enhance osteoblast responses and encourage further studies on MPD-based hydroxyapatite coatings on Ti for improved orthopedic applications. Keywords: hydroxyapatite, anodization, nanotechnology

  11. In-situ IR spectroscopy to study anodic oxidation of Si(111) in KOH solution

    NARCIS (Netherlands)

    Philipsen, H.G.G.; Chazalviel, J.-N.; Allongue, P.; Ozanam, F.; Kelly, J.J.

    2007-01-01

    Fourier Transform Infrared (FTIR) spectroscopy was used to study in-situ the anodic oxidation of n-type Si(111) in KOH solution. Changes in surface chemistry were followed during oxide growth. The results are considered on the basis of a model developed from electrochemical measurements.

  12. Role of surfactant-mediated electrodeposited titanium oxide substrate in improving electrocatalytic features of supported platinum particles

    Energy Technology Data Exchange (ETDEWEB)

    Spătaru, Tanţa; Preda, Loredana; Osiceanu, Petre; Munteanu, Cornel; Anastasescu, Mihai; Marcu, Maria; Spătaru, Nicolae, E-mail: nspataru@icf.ro

    2014-01-01

    A new hybrid system with improved photocatalytic and electrocatalytic performances was obtained by two-step potentiostatic deposition on highly boron-doped diamond (BDD) substrate. First, hydrated TiO{sub 2} was anodically deposited from a TiCl{sub 3} aqueous solution, both in the presence and in the absence of sodium dodecyl sulfate (SDS). The study of the UV irradiation effect evidenced that titanium oxide coatings obtained by surfactant-assisted electrodeposition (TiO{sub 2}:SDS) exhibit enhanced photocurrent, due to its very rough texonsture and presumably to better efficiency of charge carrier separation. Electrochemical deposition of platinum on the oxide-coated BDD was carried out in a second step and AFM, SEM and XPS measurements have shown that, on the TiO{sub 2}:SDS substrate, Pt particles are smaller, more uniformly distributed, and tend to form clusters, leading to a specific surface area of the electrocatalyst of ca. 6.55 m{sup 2} g{sup −1}. Carbon monoxide stripping experiments demonstrated that, when deposited on TiO{sub 2}:SDS, Pt particles are also less sensitive to CO-poisoning during methanol anodic oxidation.

  13. A new titanium oxide index in the visual band

    Science.gov (United States)

    Bidaran, Bahar; Mirtorabi, Mohammad Taghi; Azizi, Fatemeh

    2016-04-01

    We introduce a new colour index consisting of two spectral bandwidths to measure the titanium oxide (TiO) absorption band strength centred at 567 nm. Based on the most up-to-date line list for TiO, we regenerate a grid of synthesized spectra and investigate the temperature sensitivity of the index. The new index behaves similarly to the older TiO index of Wing, in that it decreases monotonically from the coolest atmosphere with Teff = 2800 up to Teff = 4000 where the TiO molecules disassociate. To further examine the feasibility of the new index, we reproduce the calibration using a list of observed high-resolution spectra and we find similar results. This index extends the TiO absorption band capability to measure the effective temperatures of late K to M stars to the visual spectrum, where it is more accessible to small telescopes for long-term dedicated observation.

  14. Tunable Nanostructures and Crystal Structures in Titanium Oxide Films

    Directory of Open Access Journals (Sweden)

    Fuess H

    2008-01-01

    Full Text Available Abstract Controllable nanostructures in spin coated titanium oxide (TiO2 films have been achieved by a very simple means, through change of post deposition annealing temperature. Electron beam imaging and reciprocal space analysis revealed as-deposited TiO2films to be characterized by a dominant anatase phase which converts to the rutile form at 600 °C and reverts to the anatase modification at 1,200 °C. The phase changes are also accompanied by changes in the film microstructure: from regular nanoparticles (as-deposited to nanowires (600 °C and finally to dendrite like shapes at 1,200 °C. Photoluminescence studies, Raman spectral results, and X-ray diffraction data also furnish evidence in support of the observed solid state phase transformations in TiO2.

  15. Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

    Science.gov (United States)

    Karjalainen, Pasi P; Nammas, Wail

    2017-06-01

    Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

  16. Development and Testing of High Surface Area Iridium Anodes for Molten Oxide Electrolysis

    Science.gov (United States)

    Shchetkovskiy, Anatoliy; McKechnie, Timothy; Sadoway, Donald R.; Paramore, James; Melendez, Orlando; Curreri, Peter A.

    2010-01-01

    Processing of lunar regolith into oxygen for habitat and propulsion is needed to support future space missions. Direct electrochemical reduction of molten regolith is an attractive method of processing, because no additional chemical reagents are needed. The electrochemical processing of molten oxides requires high surface area, inert anodes. Such electrodes need to be structurally robust at elevated temperatures (1400-1600?C), be resistant to thermal shock, have good electrical conductivity, be resistant to attack by molten oxide (silicate), be electrochemically stable and support high current density. Iridium with its high melting point, good oxidation resistance, superior high temperature strength and ductility is the most promising candidate for anodes in high temperature electrochemical processes. Several innovative concepts for manufacturing such anodes by electrodeposition of iridium from molten salt electrolyte (EL-Form? process) were evaluated. Iridium electrodeposition to form of complex shape components and coating was investigated. Iridium coated graphite, porous iridium structure and solid iridium anodes were fabricated. Testing of electroformed iridium anodes shows no visible degradation. The result of development, manufacturing and testing of high surface, inert iridium anodes will be presented.

  17. Synthesis of manganese oxide supported on mesoporous titanium oxide: Influence of the block copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, F. [Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Bât. Berthollet, Université Claude Bernard—Lyon 1, 43 Bd 11 novembre 1918, 69622 Villeurbanne (France); IRCELYON, Institut de recherches sur la catalyse et l’environnement de Lyon (UMR 5256 CNRS/Université Lyon 1), Lyon (France); Bois, L., E-mail: laurence.bois@univ-lyon1.fr [Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Bât. Berthollet, Université Claude Bernard—Lyon 1, 43 Bd 11 novembre 1918, 69622 Villeurbanne (France); Chiriac, R.; Toche, F.; Chassagneux, F. [Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Bât. Berthollet, Université Claude Bernard—Lyon 1, 43 Bd 11 novembre 1918, 69622 Villeurbanne (France); Besson, M.; Descorme, C. [IRCELYON, Institut de recherches sur la catalyse et l’environnement de Lyon (UMR 5256 CNRS/Université Lyon 1), Lyon (France); Khrouz, L. [ENS LYON Laboratoire de Chimie (LR6, site Monod), 46, allée d’Italie, 69364 Lyon Cedex 07 (France)

    2015-01-15

    Manganese oxides supported on mesoporous titanium oxides were synthesized via a sol–gel route using block copolymer self-assembly. The oxides were characterized by X-ray diffraction, infrared spectroscopy, thermal analyses, nitrogen adsorption/desorption, electron microscopy and electronic paramagnetic resonance. A mesoporous anatase containing amorphous manganese oxide particles could be obtained with a 0.2 Mn:Ti molar ratio. At higher manganese loading (0.5 Mn:Ti molar ratio), segregation of crystalline manganese oxide occurred. The influence of block copolymer and manganese salt on the oxide structure was discussed. The evolution of the textural and structural characteristics of the materials upon hydrothermal treatment was also investigated. - Graphical abstract: One-pot amorphous MnO{sub 2} supported on mesoporous anataseTiO{sub 2}. - Highlights: • Mesoporous manganese titanium oxides were synthesized using block copolymer. • Block copolymers form complexes with Mn{sup 2+} from MnCl{sub 2}. • With block copolymer, manganese oxide can be dispersed around the titania crystallites. • With Mn(acac){sub 2}, manganese is dispersed inside titania. • MnOOH crystallizes outside mesoporous titania during hydrothermal treatment.

  18. Hydrogen oxidation reaction at the Ni/YSZ anode of solid oxide fuel cells from first principles.

    Science.gov (United States)

    Cucinotta, Clotilde S; Bernasconi, Marco; Parrinello, Michele

    2011-11-11

    By means of ab initio simulations we here provide a comprehensive scenario for hydrogen oxidation reactions at the Ni/zirconia anode of solid oxide fuel cells. The simulations have also revealed that in the presence of water chemisorbed at the oxide surface, the active region for H oxidation actually extends beyond the metal/zirconia interface unraveling the role of water partial pressure in the decrease of the polarization resistance observed experimentally.

  19. Titanium-Manganese Oxides. Optical and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    V. Chernyak

    2010-01-01

    Full Text Available Nanocrystalline titanium-manganese mixed oxides (ТМО with the Mn content of 13÷16 % at. were first synthesized by manganese hydroxide precipitation on anatase or rutile particles. The structure, morphology and chemical composition of the samples were characterized using XRD and XRF methods showing that the synthesized mixed oxides are the polydisperse materials of different phase composition containing TiO2, Mn2O3 and MnTiO3. The phase transformations and structure defects of the prepared compounds were characterized by FTIR, FT-FIR, FT-Raman spectroscopies. UV-VIS absorption spectra were investigated in 2,4÷6,0 eV region, and it was revealed that the presence of manganese oxides results in absorption increase and significant red shift of the ТМО absorption edge in comparison with pure TiO2. Photocatalytic activity of pure TiO2, Mn2+-doped TiO2 and ТМО during the photocatalytic decomposition of the safranine dye under UV irradiation was studied. A great improvement of photocatalytic activity is registered for Mn2+-doped TiO2 (anatase and rutile, and rutile-based ТМО sample.

  20. Characterization of microarc oxidation coatings on pure titanium

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The morphology, composition, and phase structure of the oxide coatings produced on the surface of pure titaniumby alternating-current microarc discharge in aluminate solution were investigated by X-ray diffraction and scanning electronmicroscopy. The profiles of the hardness H and the elastic modulus E in the coatings were determined using a nanoindenta-tion method. The concentration distributions of Ti, Al, and O in the coating show that this coating over 30 μm thick containstwo layers: an outer layer and an inner layer. The oxide coating is mainly composed of TiO2 rutile and Al2TiO5 compounds.During oxidation, the temperature in the microarc discharge channel was very high to make the local coating molten. Fromthe surface to the interior of the coating, H and E increase gradually, and then reach maximum values of 9.78 GPa and 176GPa respectively at a distance of 7 μm from the coating/titanium interface. They are also rather high near the interface.

  1. Potentiodynamic behaviour of mechanically polished titanium electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Camara, O.R.; DePauli, C.P.; Giordano, M.C.

    1984-08-01

    The behaviour of titanium electrodes mechanically polished and/or anodically polarized at low positive potential in solutions at constant ionic strength between pH 0.3 and 11.0 is reported. The oxide electroformation potential on a mechanically polished electrode shows a complex dependence on the bulk solution pH. This dependence is similar to that obtained through acid-base titration with titanium as the indicating electrode. The formation of hydroxo-complexes on the spontaneously formed titanium oxide offers a possible explanation for the oxide electroformation potential dependence on pH. Anodic and cathodic wide current peaks are obtained between the potential of the hydrogen evolution and that of the massive oxide electroformation; the corresponding redox system becomes evident at pH 4.0 from the first potentiodynamic cycle. An interpretation of these processes involving the participation of non stoichiometric oxides and hydrogen ions is attempted.

  2. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Science.gov (United States)

    Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

    2012-01-01

    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

  3. Electrowinning molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  4. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    Science.gov (United States)

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  5. Direct methane solid oxide fuel cells based on catalytic partial oxidation enabling complete coking tolerance of Ni-based anodes

    Science.gov (United States)

    Lee, Daehee; Myung, Jaeha; Tan, Jeiwan; Hyun, Sang-Hoon; Irvine, John T. S.; Kim, Joosun; Moon, Jooho

    2017-03-01

    Solid oxide fuel cells (SOFCs) can oxidize diverse fuels by harnessing oxygen ions. Benefited by this feature, direct utilization of hydrocarbon fuels without external reformers allows for cost-effective realization of SOFC systems. Superior hydrocarbon reforming catalysts such as nickel are required for this application. However, carbon coking on nickel-based anodes and the low efficiency associated with hydrocarbon fueling relegate these systems to immature technologies. Herein, we present methane-fueled SOFCs operated under conditions of catalytic partial oxidation (CPOX). Utilizing CPOX eliminates carbon coking on Ni and facilitates the oxidation of methane. Ni-gadolinium-doped ceria (GDC) anode-based cells exhibit exceptional power densities of 1.35 W cm-2 at 650 °C and 0.74 W cm-2 at 550 °C, with stable operation over 500 h, while the similarly prepared Ni-yttria stabilized zirconia anode-based cells exhibit a power density of 0.27 W cm-2 at 650 °C, showing gradual degradation. Chemical analyses suggest that combining GDC with the Ni anode prevents the oxidation of Ni due to the oxygen exchange ability of GDC. In addition, CPOX operation allows the usage of stainless steel current collectors. Our results demonstrate that high-performance SOFCs utilizing methane CPOX can be realized without deterioration of Ni-based anodes using cost-effective current collectors.

  6. Development of Oxidation Protection Coatings for Gamma Titanium Aluminide Alloys

    Science.gov (United States)

    Wallace, T. A.; Bird, R. K.; Sankaran, S. N.

    2003-01-01

    Metallic material systems play a key role in meeting the stringent weight and durability requirements for reusable launch vehicle (RLV) airframe hot structures. Gamma titanium aluminides (gamma-TiAl) have been identified as high-payoff materials for high-temperature applications. The low density and good elevated temperature mechanical properties of gamma-TiAl alloys make them attractive candidates for durable lightweight hot structure and thermal protection systems at temperatures as high as 871 C. However, oxidation significantly degrades gamma-TiAl alloys under the high-temperature service conditions associated with the RLV operating environment. This paper discusses ongoing efforts at NASA Langley Research Center to develop durable ultrathin coatings for protecting gamma-TiAl alloys from high-temperature oxidation environments. In addition to offering oxidation protection, these multifunctional coatings are being engineered to provide thermal control features to help minimize heat input into the hot structures. This paper describes the coating development effort and discusses the effects of long-term high-temperature exposures on the microstructure of coated and uncoated gamma-TiAl alloys. The alloy of primary consideration was the Plansee alloy gamma-Met, but limited studies of the newer alloy gamma-Met-PX were also included. The oxidation behavior of the uncoated materials was evaluated over the temperature range of 704 C to 871 C. Sol-gel-based coatings were applied to the gamma-TiAl samples by dipping and spraying, and the performance evaluated at 871 C. Results showed that the coatings improve the oxidation resistance, but that further development is necessary.

  7. Influence of anodization parameters on the volume expansion of anodic aluminum oxide formed in mixed solution of phosphoric and oxalic acids

    Science.gov (United States)

    Kao, Tzung-Ta; Chang, Yao-Chung

    2014-01-01

    The growth of anodic alumina oxide was conducted in the mixed solution of phosphoric and oxalic acids. The influence of anodizing voltage, electrolyte temperature, and concentration of phosphoric and oxalic acids on the volume expansion of anodic aluminum oxide has been investigated. Either anodizing parameter is chosen to its full extent of range that allows the anodization process to be conducted without electric breakdown and to explore the highest possible volume expansion factor. The volume expansion factors were found to vary between 1.25 and 1.9 depending on the anodizing parameters. The variation is explained in connection with electric field, ion transport number, temperature effect, concentration, and activity of acids. The formation of anodic porous alumina at anodizing voltage 160 V in 1.1 M phosphoric acid mixed with 0.14 M oxalic acid at 2 °C showed the peak volume expansion factor of 1.9 and the corresponding moderate growth rate of 168 nm/min.

  8. Synthesis of Nanorods Titanium Dioxide via Anodic Alumina Membrane Template and their Applications in Dye-Sensitized Solar Cells

    Science.gov (United States)

    Suryana, R.; Sehati; Kusumandari

    2016-08-01

    Titanium dioxide (TiO2) nanorods have been successfully synthesized through sol- gel method via Anodic Alumina Membrane (AAM) as template. AAM template was removed using 6 M NaOH solution to obtain TiO2 nanorods only. Then TiO2 nanorods were annealed at 400°C for 2 h. Phase TiO2 nanorods were characterized using X-Ray Diffraction (XRD) and morphology of TiO2 nanorods were observed using Atomic Force Microscopy (AFM). In addition, the I-V meter was used to determine the DSSC efficiency. The XRD patterns showed that all peaks of synthesized-TiO2 indicated anatase phase. AFM images confirmed that TiO2 nanorods have diameters in range 18-30 nm. TiO2 nanorods were mixed with TiO2 nanoparticles having 21 nm in size then it was applied in the DSSC with p-carotene from carrot as dye. The efficiency of DSSC using TiO2 mixed-nanorods and nanoparticles increase about 154.20% compare to using TiO2 nanoparticles only. It is considered that TiO2 nanorod structures can be effective in photon trapping thus many photon interact to dyes to produce many excited-electrons.

  9. Mechanical and Abrasive Wear Properties of Anodic Oxide Layers Formed on Aluminium

    Institute of Scientific and Technical Information of China (English)

    W.Bensalah; K.Elleuch; M.Feki; M.Wery; H.F.Ayedi

    2009-01-01

    Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The Vickers microhardness, D (HV0.2). and the abrasion weight loss, Wa (mg) were measured. Influence of oxalic acid concentration (Cox), bath temperature (T) and anodic current density (J) on D and Wa has been examined, and the sulphuric acid concentration (Caul) was maintained at 160 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), optical microscopy and glow-discharge optical emission spectroscopy (GDOES). It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

  10. A novel Ni/ceria-based anode for metal-supported solid oxide fuel cells

    Science.gov (United States)

    Rojek-Wöckner, Veronika A.; Opitz, Alexander K.; Brandner, Marco; Mathé, Jörg; Bram, Martin

    2016-10-01

    For optimization of ageing behavior, electrochemical performance, and sulfur tolerance of metal-supported solid oxide fuel cells a new anode concept is introduced, which is based on a Ni/GDC cermet replacing the established Ni/YSZ anodes. In the present work optimized processing parameters compatible with MSC substrates are specified by doing sintering studies on pressed bulk specimen and on real porous anode structures. The electrochemical performance of the Ni/GDC anodes was characterized by means of symmetrical electrolyte supported model-type cells. In this study, three main objectives are pursued. Firstly, the effective technical realization of the Ni/GDC concept is demonstrated. Secondly, the electrochemical behavior of Ni/GDC porous anodes is characterized by impedance spectroscopy and compared with the current standard Ni/YSZ anode. Further, a qualitative comparison of the sulfur poisoning behavior of both anode types is presented. Thirdly, preliminary results of a successful implementation of the Ni/GDC cermet into a metal-supported single cell are presented.

  11. Fabrication of diameter-modulated and ultrathin porous nanowires in anodic aluminum oxide templates

    Energy Technology Data Exchange (ETDEWEB)

    Sulka, Grzegorz D., E-mail: Sulka@chemia.uj.edu.pl [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Department of Physical Chemistry and Electrochemistry, Jagiellonian University, Ingardena 3, 30060 Krakow (Poland); Brzozka, Agnieszka [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Al. Mickiewicza 30, Krakow 30-059 (Poland); Liu, Lifeng [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany)

    2011-05-30

    Graphical abstract: Display Omitted Highlights: > AAO templates with modulated pore diameter were fabricated by pulse anodization. > HA pulse duration tunes the shape of pores and the structure of AAO channels. > Au, Ag, Ni and Ag-Au diameter-modulated nanowires were synthetized. > Porous ultrathin Au nanowires were obtained by dealloying Ag-Au nanowires. - Abstract: Anodic aluminum oxide (AAO) membranes with modulated pore diameter were synthesized by pulse anodization in 0.3 M sulfuric acid at 1 deg. C. For AAO growth, a typical combination of alternating mild anodizing (MA) and hard anodizing (HA) pulses with applied potential pulses of 25 V and 35 V was applied. The control of the duration of HA pulses will provide an interesting way to tune the shape of pores and the structure of AAO channels. It was found that a non-uniform length of HA segments in cross section of AAO is usually observed when the HA pulse duration is shorter than 1.2 s. The pulse anodization performed with longer HA pulses leads to the formation of AAO templates with periodically modulated pore diameter and nearly uniform length of segments. Various diameter-modulated metallic nanowires (Au, Ag, Ni and Ag-Au) were fabricated by electrodeposition in the pores of anodic alumina membranes. A typical average nanowire diameter was about 30 nm and 48 nm for MA and HA nanowire segments, respectively. After a successful dealloying silver from Ag-Au nanowires, porous ultrathin Au nanowires were obtained.

  12. Formation of Al-Si Composite Oxide Film by Hydrolysis Precipitation and Anodizing

    Institute of Scientific and Technical Information of China (English)

    Zhe-Sheng Feng; Ying-Jie Xia; Jia Ding; Jin-Ju Chen

    2007-01-01

    This paper presents a new technique in the high dielectric constant composite oxide film preparation.On the basis of nanocompsite high dielectric constant aluminum oxide film growth technology, a new idea of adulterating Si oxide species into the aluminum composite film was proposed. As a result, the specific capacitance and withstanding voltage of the composite oxide film formed at the anodizing voltage of 20V are enhanced, and the leakage current of the aluminum composite oxide film is reduced through incorporation of Si oxide species.

  13. Surface thermal oxidation on titanium implants to enhance osteogenic activity and in vivo osseointegration

    Science.gov (United States)

    Wang, Guifang; Li, Jinhua; Lv, Kaige; Zhang, Wenjie; Ding, Xun; Yang, Guangzheng; Liu, Xuanyong; Jiang, Xinquan

    2016-08-01

    Thermal oxidation, which serves as a low-cost, effective and relatively simple/facile method, was used to modify a micro-structured titanium surface in ambient atmosphere at 450 °C for different time periods to improve in vitro and in vivo bioactivity. The surface morphology, crystallinity of the surface layers, chemical composition and chemical states were evaluated by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Cell behaviours including cell adhesion, attachment, proliferation, and osteogenic differentiation were observed in vitro study. The ability of the titanium surface to promote osseointegration was evaluated in an in vivo animal model. Surface thermal oxidation on titanium implants maintained the microstructure and, thus, both slightly changed the nanoscale structure of titanium and enhanced the crystallinity of the titanium surface layer. Cells cultured on the three oxidized titanium surfaces grew well and exhibited better osteogenic activity than did the control samples. The in vivo bone-implant contact also showed enhanced osseointegration after several hours of oxidization. This heat-treated titanium enhanced the osteogenic differentiation activity of rBMMSCs and improved osseointegration in vivo, suggesting that surface thermal oxidation could potentially be used in clinical applications to improve bone-implant integration.

  14. Design and fabrication of novel anode flow-field for commercial size solid oxide fuel cells

    Science.gov (United States)

    Canavar, Murat; Timurkutluk, Bora

    2017-04-01

    In this study, nickel based woven meshes are tested as not only anode current collecting meshes but also anode flow fields instead of the conventional gas channels fabricated by machining. For this purpose, short stacks with different anode flow fields are designed and built by using different number of meshes with various wire diameters and widths of opening. A short stack with classical machined flow channels is also constructed. Performance and impedance measurements of the short stacks with commercial size cells of 81 cm2 active area are performed and compared. The results reveal that it is possible to create solid oxide fuel cell anode flow fields with woven meshes and obtain acceptable power with a proper selection of the mesh number, type and orientation.

  15. Evolution of insoluble eutectic Si particles in anodic oxidation films during adipic-sulfuric acid anodizing processes of ZL114A aluminum alloys

    Science.gov (United States)

    Hua, Lei; Liu, Jian-hua; Li, Song-mei; Yu, Mei; Wang, Lei; Cui, Yong-xin

    2015-03-01

    The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The anodic oxidation was performed at 25°C and a constant voltage of 15 V in a solution containing 50 g/L sulfuric acid and 10 g/L adipic acid. The thickness of the formed anodic oxidation film was approximately 7.13 μm. The interpore distance and the diameters of the major pores in the porous layer of the film were within the approximate ranges of 10-20 nm and 5-10 nm, respectively. Insoluble eutectic Si particles strongly influenced the morphology of the anodic oxidation films. The anodic oxidation films exhibited minimal defects and a uniform thickness on the ZL114A substrates; in contrast, when the front of the oxide oxidation films encountered eutectic Si particles, defects such as pits and non-uniform thickness were observed, and pits were observed in the films.

  16. Durability Prediction of Solid Oxide Fuel Cell Anode Material under Thermo-Mechanical and Fuel Gas Contaminants Effects

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Gulfam; Guo, Hua; Kang , Bruce S.; Marina, Olga A.

    2011-01-10

    Solid Oxide Fuel Cells (SOFCs) operate under harsh environments, which cause deterioration of anode material properties and service life. In addition to electrochemical performance, structural integrity of the SOFC anode is essential for successful long-term operation. The SOFC anode is subjected to stresses at high temperature, thermal/redox cycles, and fuel gas contaminants effects during long-term operation. These mechanisms can alter the anode microstructure and affect its electrochemical and structural properties. In this research, anode material degradation mechanisms are briefly reviewed and an anode material durability model is developed and implemented in finite element analysis. The model takes into account thermo-mechanical and fuel gas contaminants degradation mechanisms for prediction of long-term structural integrity of the SOFC anode. The proposed model is validated experimentally using a NexTech ProbostatTM SOFC button cell test apparatus integrated with a Sagnac optical setup for simultaneously measuring electrochemical performance and in-situ anode surface deformation.

  17. Degradation of atrazine by electrochemical advanced oxidation processes using a boron-doped diamond anode

    OpenAIRE

    Borràs Cristòfol, Núria; Oliver Pujol, Ramon; Arias Tejerina, Concha; Brillas Coso, Enric

    2010-01-01

    Solutions of 30 mg L-1 of the herbicide atrazine have been degraded by environmentally friendly electrochemical advanced oxidation processes (EAOPs) such as anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) using a small open and cylindrical cell with a boron-doped diamond (BDD) anode. AO has been carried out either with a stainless steel cathode or an O2 diffusion cathode able to generate H2O2. Hydroxyl radicals (•OH) formed at the BDD surface in all EAOPs and in t...

  18. Studies on anodic oxide coating with low absorptance and high emittance on aluminum alloy 2024

    Energy Technology Data Exchange (ETDEWEB)

    Siva Kumar, C. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India); Sharma, A.K. [Thermal Process Section, ISRO Satellite Centre, Vimanapura Post, Bangalore (India); Mahendra, K.N.; Mayanna, S.M. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India)

    2000-01-01

    Anodization of AA 2024 in sulfuric acid bath containing glycerol, lactic acid and ammonium metavenadate has been studied to develop white anodic oxide coating. Investigation on the influence of various operating parameters - coating thickness, current density and ammonium metavenadate concentration on the optical properties was carried out to optimize the process. Infrared, atomic absorption spectroscopic techniques and scanning electron micrograph were used to characterize the coating. The obtained oxide coating provides a ratio of solar absorptance ({alpha}) to infrared emittance ({epsilon}), as low as 0.2. The optical properties and hardness values measured under optimum experimental conditions support its use as a thermal control coating.

  19. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    OpenAIRE

    2015-01-01

    This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO) layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodisin...

  20. Surface electronic and structural properties of nanostructured titanium oxide grown by pulsed laser deposition

    NARCIS (Netherlands)

    Fusi, M.; Maccallini, E.; Caruso, T.; Casari, C. S.; Bassi, A. Li; Bottani, C. E.; Rudolf, P.; Prince, K. C.; Agostino, R. G.

    2011-01-01

    Titanium oxide nanostructured thin films synthesized by pulsed laser deposition (PLD) were here characterized with a multi-technique approach to investigate the relation between surface electronic, structural and morphological properties. Depending on the growth parameters, these films present chara

  1. Photocatalytic Decolourization of Direct Yellow 9 on Titanium and Zinc Oxides

    Directory of Open Access Journals (Sweden)

    Elżbieta Regulska

    2013-01-01

    Full Text Available The photodecolourization of Direct Yellow 9, a member of the group of azo dyes which are commonly used in the various branches of the industry, was investigated. The photostability of this dye was not previously examined. Photocatalytic degradation method was evaluated. Solar simulated light (E=500 W/m2, titanium dioxide, and zinc oxide were used as irradiation source and photocatalysts, respectively. Kinetic studies were performed on a basis of a spectrophotometric method. Degradation efficiency was assessed by applying high performance liquid chromatography. Disappearance of a dye from titanium dioxide and zinc oxide surfaces after degradation was confirmed by thermogravimetry and Raman microscopy. Direct Yellow 9 was found to undergo the photodegradation with approximately two times higher efficiency when zinc oxide was applied in comparison with titanium dioxide. A simple and promising way to apply the photocatalytic removal of Direct Yellow 9 in titanium dioxide and zinc oxide suspensions was presented.

  2. Electrochemical oxidation of imazapyr with BDD electrode in titanium substrate.

    Science.gov (United States)

    Souza, F L; Teodoro, T Q; Vasconcelos, V M; Migliorini, F L; Lima Gomes, P C F; Ferreira, N G; Baldan, M R; Haiduke, R L A; Lanza, M R V

    2014-12-01

    In this work we have studied the treatment of imazapyr by electrochemical oxidation with boron-doped diamond anode. Electrochemical degradation experiments were performed in a one-compartment cell containing 0.45 L of commercial formulations of herbicide in the pH range 3.0-10.0 by applying a density current between 10 and 150 mA cm(-2) and in the temperature range 25-45 °C. The maximum current efficiencies were obtained at lower current densities since the electrochemical system is under mass transfer control. The mineralization rate increased in acid medium and at higher temperatures. The treatment was able to completely degrade imazapyr in the range 4.6-100.0 mg L(-1), although the current charge required rises along with the increasing initial concentration of the herbicide. Toxicity analysis with the bioluminescent bacterium Vibrio fischeri showed that at higher pollutant concentrations the toxicity was reduced after the electrochemical treatment. To clarify the reaction pathway for imazapyr mineralization by OH radicals, LC-MS/MS analyses we performed together with a theoretical study. Ions analysis showed the formation of high levels of ammonium in the cathode. The main final products of the electrochemical oxidation of imazapyr with diamond thin film electrodes are formic, acetic and butyric acids.

  3. Hierarchically oriented macroporous anode-supported solid oxide fuel cell with thin ceria electrolyte film.

    Science.gov (United States)

    Chen, Yu; Zhang, Yanxiang; Baker, Jeffrey; Majumdar, Prasun; Yang, Zhibin; Han, Minfang; Chen, Fanglin

    2014-04-09

    Application of anode-supported solid oxide fuel cell (SOFC) with ceria based electrolyte has often been limited by high cost of electrolyte film fabrication and high electrode polarization. In this study, dense Gd0.1Ce0.9O2 (GDC) thin film electrolytes have been fabricated on hierarchically oriented macroporous NiO-GDC anodes by a combination of freeze-drying tape-casting of the NiO-GDC anode, drop-coating GDC slurry on NiO-GDC anode, and co-firing the electrolyte/anode bilayers. Using 3D X-ray microscopy and subsequent analysis, it has been determined that the NiO-GDC anode substrates have a porosity of around 42% and channel size from around 10 μm at the electrolyte side to around 20 μm at the other side of the NiO-GDC (away from the electrolyte), indicating a hierarchically oriented macroporous NiO-GDC microstructure. Such NiO-GDC microstructure shows a tortuosity factor of ∼1.3 along the thickness direction, expecting to facilitate gas diffusion in the anode during fuel cell operation. SOFCs with such Ni-GDC anode, GDC film (30 μm) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3-GDC (LSCF-GDC) cathode show significantly enhanced cell power output of 1.021 W cm(-2) at 600 °C using H2 as fuel and ambient air as oxidant. Electrochemical Impedance Spectroscopy (EIS) analysis indicates a decrease in both activation and concentration polarizations. This study has demonstrated that freeze-drying tape-casting is a very promising approach to fabricate hierarchically oriented porous substrate for SOFC and other applications.

  4. Synthesis, Characterization, and Optimization of Novel Solid Oxide Fuel Cell Anodes

    Science.gov (United States)

    Miller, Elizabeth C.

    This dissertation presents research on the development of novel materials and fabrication procedures for solid oxide fuel cell (SOFC) anodes. The work discussed here is divided into three main categories: all-oxide anodes, catalyst exsolution oxide anodes, and Ni-infiltrated anodes. The all-oxide and catalyst exsolution anodes presented here are further classi?ed as Ni-free anodes operating at the standard 700-800°C SOFC temperature while the Ni-infiltrated anodes operate at intermediate temperatures (≤650°C). Compared with the current state-of-the-art Ni-based cermets, all-oxide, Ni-free SOFC anodes offer fewer coking issues in carbon-containing fuels, reduced degradation due to fuel contaminants, and improved stability during redox cycling. However, electrochemical performance has proven inferior to Ni-based anodes. The perovskite oxide Fe-substituted strontium titanate (STF) has shown potential as an anode material both as a single phase electrode and when combined with Gd-doped ceria (GDC) in a composite electrode. In this work, STF is synthesized using a modified Pechini processes with the aim of reducing STF particle size and increasing the electrochemically active area in the anode. The Pechini method produced particles ? 750 nm in diameter, which is signi°Cantly smaller than the typically micron-sized solid state reaction powder. In the first iteration of anode fabrication with the Pechini powder, issues with over-sintering of the small STF particles limited gas di?usion in the anode. However, after modifying the anode firing temperature, the Pechini cells produced power density comparable to solid state reaction based cells from previous work by Cho et al. Catalyst exsolution anodes, in which metal cations exsolve out of the lattice under reducing conditions and form nanoparticles on the oxide surface, are another Ni-free option for standard operating temperature SOFCs. Little information is known about the onset of nanoparticle formation, which

  5. Investigation of the growth and local stoichiometric point group symmetry of titania nanotubes during potentiostatic anodization of titanium in phosphate electrolytes

    Science.gov (United States)

    Cummings, F. R.; Muller, T. F. G.; Malgas, G. F.; Arendse, C. J.

    2015-10-01

    Potentiostatic anodization of commercially pure, 50 μm-thick titanium (Ti) foil was performed in aqueous, phosphate electrolytes at increasing experimental timeframes at a fixed applied potential for the synthesis of titania nanotube arrays (TNAs). High resolution scanning electron microscopy images, combined with energy dispersive spectroscopy and x-ray diffraction spectra reveal that anodization of the Ti foil in a 1 M NaF+0.5 M H3PO4 electrolyte for 4 h yields a titanate surface with pore diameters ranging between 100 and 500 nm. The presence of rods on the Ti foil surface with lengths exceeding 20 μm and containing high concentrations of phosphor on the exterior was also detected at these conditions, along with micro-sized coral reef-like titanate balls. We propose that the formation of these structures play a major role during the anodization process and impedes nanotube growth during the anodization process. High spatially resolved scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) performed along the length of a single anodized TiO2 nanotube reveals a gradual evolution of the nanotube crystallinity, from a rutile-rich bottom to a predominantly anatase TiO2 structure along its length.

  6. Preparation and analysis of anodic aluminum oxide films with continuously tunable interpore distances

    Science.gov (United States)

    Qin, Xiufang; Zhang, Jinqiong; Meng, Xiaojuan; Deng, Chenhua; Zhang, Lifang; Ding, Guqiao; Zeng, Hao; Xu, Xiaohong

    2015-02-01

    Nanoporous anodic aluminum oxides are often used as templates for preparation of nanostructures such as nanodot, nanowire and nanotube arrays. The interpore distance of anodic aluminum oxide is the most important parameter in controlling the periodicity of these nanostructures. Herein we demonstrate a simple and yet powerful method to fabricate ordered anodic aluminum oxides with continuously tunable interpore distances. By using mixed solution of citric and oxalic acids with different molar ratio, the range of anodizing voltages within which self-ordered films can be formed were extended to between 40 and 300 V, resulting in the interpore distances change from 100 to 750 nm. Our work realized very broad range of interpore distances in a continuously tunable fashion and the experiment processes are easily controllable and reproducible. The dependence of the interpore distances on acid ratios in mixed solutions was discussed through analysis of anodizing current and it was found that the effective dissociation constant of the mixed acids is of great importance. The interpore distances achieved are comparable to wavelengths ranging from UV to near IR, and may have potential applications in optical meta-materials for photovoltaics and optical sensing.

  7. A comparative study of microcystin-LR degradation by electrogenerated oxidants at BDD and MMO anodes.

    Science.gov (United States)

    Zhou, Shiqing; Bu, Lingjun; Yu, Yanghai; Zou, Xu; Zhang, Yansen

    2016-12-01

    This study investigated the electrochemical degradation of microcystin-LR (MC-LR) using boron-doped diamond (BDD) anode and mixed metal oxides (MMO, IrO2Ta2O5/Ti) anode in different medium. In-situ electrogenerated oxidants including hydroxyl radical, active chlorine, and persulfate were confirmed in phosphate, chloride, and sulfate medium, respectively. Different from MMO anode, hydroxyl radical was observed to play a significant role in chlorine generation at BDD anode in chloride medium. Besides, BDD anode could activate sulfate electrochemically due to its high oxygen evolution potential, and MC-LR degradation rate increased with the decrease of solution pH. The effects of natural organic matters (NOM) and algal organic matters (AOM) on MC-LR degradation were evaluated and NOM presented stronger inhibition ability than AOM. Furthermore, the intermediates generated in MC-LR degradation in chloride and sulfate medium were identified by LC/MS/MS and possible degradation pathways were proposed based on the experiments results. Benzene ring and conjugated diene bonds of Adda group and double bonds of Mhda group were found to be the reactive sites of MC-LR. Overall, this study broadens the knowledge of electrochemical oxidation in removing microcystins in algae-laden water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The Catalysis of NAD+ on Methanol Anode Oxidation Electrode for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; PAN Mu; YUAN Run-zhang

    2004-01-01

    A tentative idea of developing a liquid-catalytic system on methanol anode oxidation was proposed by analyzing the characteristics of methanol anode oxidation in direct methanol fuel cell. The kinetics of methanol oxidation at a glassy carbon electrode in the presence of nicotinamide adenine dinucleotide (NAD+) was investigated. It is found that the current density of methanol oxidation increases greatly and the electrochemical reaction impedance reduces obviously in the presence of NAD+ compared with those in the absence of NAD+. The catalytic activity of NAD+ is sensitive to temperature. When the temperature preponderates over 45℃, NAD+ is out of function of catalysis for methanol oxidation, which is probably due to the denaturation of NAD+ at a relatively high temperature.

  9. Use of anodic oxide films to control the diffusion of zinc in GaAs

    Science.gov (United States)

    Cutlerywala, H.; Roedel, R. J.

    1994-06-01

    Experiments were performed to diffuse zinc into GaAs through anodic oxide layers of varying thickness and density. Using electrochemical profiling to determine both the electrically active zinc concentration and the diffusion depth with high resolution, the following results were found. The depth of the junction varies inversely with the thickness and the density of the oxide. However, the surface concentration appears to be independent of oxide thickness or density, attaining a value identical to that found for diffusion into a bare GaAs sample. These results demonstrate that the most significant impact of the oxide is to delay the introduction of the zinc into the GaAs lattice. In short, the anodic oxide cannot be used as either a mask or as a zinc concentration attenuator.

  10. A new oxyfluorinated titanium phosphate anode for a high-energy lithium-ion battery.

    Science.gov (United States)

    Ma, Zhaohui; Sun, Chunwen; Lyu, Yingchun; Wang, Yuesheng; Kim, Youngsik; Chen, Liquan

    2015-01-21

    Na3[Ti2P2O10F] was synthesized by a hydrothermal method. It has an open framework structure consisting of TiFO5 octahedra and PO4 tetrahedra. The feasibility of Na3[Ti2P2O10F] as an anode material for lithium-ion batteries was first studied. Na3[Ti2P2O10F] exhibits a reversible capacity of more than 200 mAh g(-1) at a discharge/charge current rate of 20 mA g(-1) (∼0.1 C) and 105 mA g(-1) at a discharge/charge current rate of 400 mA g(-1) (∼2 C) with a lower intercalation voltage. The result of in situ X-ray diffraction test shows the structural evolution during the first discharge/charge cycle. The structure of Na3[Ti2P2O10F] was kept during discharge/charge with a slight change of the lattice parameters, which indicates a lithium solid solution behavior.

  11. Effects of titanium surface anodization with CaP incorporation on human osteoblastic response

    Science.gov (United States)

    OLIVEIRA, Natássia Cristina Martins; MOURA, Camilla Christian Gomes; ZANETTA-BARBOSA, Darceny; MENDONÇA, Daniela Baccelli Silveira; MENDONÇA, Gustavo; DECHICHI, Paula

    2015-01-01

    In this study we investigated whether anodization with calcium phosphate (CaP) incorporation (Vulcano®) enhances growth factors secretion, osteoblast-specific gene expression, and cell viability, when compared to acid etched surfaces (Porous®) and machined surfaces (Screw®) after 3 and 7 days. Results showed significant cell viability for Porous and Vulcano at day 7, when compared with Screw (p=0.005). At the same time point, significant differences regarding runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression were found for all surfaces (p0.05). Although no significant correlation was found for growth factors secretion and Runx2 expression, a significant positive correlation between this gene and ALP/BSP expression showed that their strong association is independent on the type of surface. The incorporation of CaP affected the biological parameters evaluated similar to surfaces just acid etched. The results presented here support the observations that roughness also may play an important role in determining cell response. PMID:23498218

  12. Structure and properties of bimetallic titanium and vanadium oxide clusters.

    Science.gov (United States)

    Helmich, Benjamin; Sierka, Marek; Döbler, Jens; Sauer, Joachim

    2014-05-14

    By employing a genetic algorithm together with density functional theory (B3LYP), we investigate the most stable minimum structures of several bimetallic titanium and vanadium oxide clusters that contain four metal atoms. The following compositions are studied: VnTin-4O10(-) (n = 1-4), (TiO2)VOn(-) (n = 1-4), and (TiO2)VOn(+) (n = 1-3). Apart from (TiO2)3VO(-), vanadium oxo groups are always part of the most stable minimum structures when vanadium is present. Anti-ferromagnetic coupling lowers the energy substantially if spin centers are located at neighbored metal atoms rather than at distant oxygen radical sites. Vanadium-rich or oxygen-poor compositions prefer symmetric adamantane-like cage structures, some of which have already been proposed in a previous study. In contrast, vanadium-poor and oxygen-rich compositions show versatile structural motifs that cannot be intuitively derived from the symmetric cage motif. Particularly, for Ti4O10(-) there are several non-symmetric and distorted cages that have an up to 68 kJ mol(-1) lower energy than the symmetric adamantane-like cage structure. Nevertheless, for the adamantane-like cage the simulated infra-red spectrum (within the harmonic approximation) agrees best with the experimental vibrational spectrum. The oxidative power of the (TiO2)3VO3(-) and (TiO2)3VO2(+) clusters as measured by the energy of removing 1/2 O2 (297 and 227 kJ mol(-1), respectively) is less than that of the pure vanadium oxide clusters (V2O5)VO3(-) and (V2O5)VO2(+) (283 and 165 kJ mol(-1), respectively).

  13. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates

    Science.gov (United States)

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-01

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation. PMID:24535886

  14. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates.

    Science.gov (United States)

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-20

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation.

  15. High-Temperature Oxidation Behavior of Vanadium, Titanium-Bearing Magnetite Pellet%High-Temperature Oxidation Behavior of Vanadium, Titanium-Bearing Magnetite Pellet

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-hong; JIANG Tao; ZHANG Yuan-bo; HUANG Yan-fang; LI Guang-hui

    2011-01-01

    By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing (1 073- 1 323 K). Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature (1073-1 173 K). Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1 173-1 273 K. When oxidation temperature is higher than 1 273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-hearing magnetite pellet.

  16. A Review of RedOx Cycling of Solid Oxide Fuel Cells Anode

    Directory of Open Access Journals (Sweden)

    Jan Van herle

    2012-08-01

    Full Text Available Solid oxide fuel cells are able to convert fuels, including hydrocarbons, to electricity with an unbeatable efficiency even for small systems. One of the main limitations for long-term utilization is the reduction-oxidation cycling (RedOx cycles of the nickel-based anodes. This paper will review the effects and parameters influencing RedOx cycles of the Ni-ceramic anode. Second, solutions for RedOx instability are reviewed in the patent and open scientific literature. The solutions are described from the point of view of the system, stack design, cell design, new materials and microstructure optimization. Finally, a brief synthesis on RedOx cycling of Ni-based anode supports for standard and optimized microstructures is depicted.

  17. The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Xiao, Ruihua; Yang, Pengfei; Hu, Baofu; Yao, Xi

    2014-09-01

    The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

  18. Ni-(Ce0.8-xTix)Sm0.2O2-δ anode for low temperature solid oxide fuel cells running on dry methane fuel

    Science.gov (United States)

    Han, Bing; Zhao, Kai; Hou, Xiaoxue; Kim, Dong-Jin; Kim, Bok-Hee; Ha, Su; Norton, M. Grant; Xu, Qing; Ahn, Byung-Guk

    2017-01-01

    A titanium-doped Ce0.8Sm0.2O1.9 composite is developed as an anode component of low temperature solid oxide fuel cells running on methane fuel. Crystallographic parameters of (Ce0.8-xTix)Sm0.2O2-δ (0.00 cell consisting of Ni-(Ce0.8-xTix)Sm0.2O2-δ anode/Ce0.8Sm0.2O1.9 electrolyte/La0.6Sr0.4Co0.2Fe0.8O3-δ cathode. Catalytic properties of Ni-(Ce0.8-xTix)Sm0.2O2-δ are inspected with the electrochemical performance and performance stability of the cells in dry methane fuel. The cell with Ni-(Ce0.73Ti0.07)Sm0.2O2-δ (x = 0.07) anode displays a low polarization resistance and an optimum maximum power density (679 mW cm-2 at 600 °C). A performance stability investigation indicates that the cell exhibits a fairly low degradation rate of 3 mV h-1 during a 31 h operation in dry methane. These findings suggest the application potential of the titanium doped Ce0.8Sm0.2O1.9 for the anode of solid oxide fuel cells.

  19. Preparation and Evaluation of Multi-Layer Anodes of Solid Oxide Fuel Cell

    Science.gov (United States)

    Santiago, Diana; Farmer, Serene C.; Setlock, John A.

    2012-01-01

    The development of an energy device with abundant energy generation, ultra-high specific power density, high stability and long life is critical for enabling longer missions and for reducing mission costs. Of all different types of fuel cells, the solid oxide fuel cells (SOFC) is a promising high temperature device that can generate electricity as a byproduct of a chemical reaction in a clean way and produce high quality heat that can be used for other purposes. For aerospace applications, a power-to-weight of (is) greater than 1.0 kW/kg is required. NASA has a patented fuel cell technology under development, capable of achieving the 1.0 kW/kg figure of merit. The first step toward achieving these goals is increasing anode durability. The catalyst plays an important role in the fuel cells for power generation, stability, efficiency and long life. Not only the anode composition, but its preparation and reduction are key to achieving better cell performance. In this research, multi-layer anodes were prepared varying the chemistry of each layer to optimize the performance of the cells. Microstructure analyses were done to the new anodes before and after fuel cell operation. The cells' durability and performance were evaluated in 200 hrs life tests in hydrogen at 850 C. The chemistry of the standard nickel anode was modified successfully reducing the anode degradation from 40% to 8.4% in 1000 hrs and retaining its microstructure.

  20. Effect of Graphene-Graphene Oxide Modified Anode on the Performance of Microbial Fuel Cell

    Directory of Open Access Journals (Sweden)

    Na Yang

    2016-09-01

    Full Text Available The inferior hydrophilicity of graphene is an adverse factor to the performance of the graphene modified anodes (G anodes in microbial fuel cells (MFCs. In this paper, different amounts of hydrophilic graphene oxide (GO were doped into the modification layers to elevate the hydrophilicity of the G anodes so as to further improve their performance. Increasing the GO doped ratio from 0.15 mg·mg−1 to 0.2 mg·mg−1 and 0.25 mg·mg−1, the static water contact angle (θc of the G-GO anodes decreased from 74.2 ± 0.52° to 64.6 ± 2.75° and 41.7 ± 3.69°, respectively. The G-GO0.2 anode with GO doped ratio of 0.2 mg·mg−1 exhibited the optimal performance and the maximum power density (Pmax of the corresponding MFC was 1100.18 mW·m−2, 1.51 times higher than that of the MFC with the G anode.

  1. Fabrication of Polymeric Antireflection Film Manufactured by Anodic Aluminum Oxide Template on Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jenn-Kai Tsai

    2017-03-01

    Full Text Available In this study, high energy conversion efficient dye-sensitized solar cells (DSSCs were successfully fabricated by attaching a double anti-reflection (AR layer, which is composed of a subwavelength moth-eye structured polymethyl methacrylate (PMMA film and a polydimethylsiloxane (PDMS film. An efficiency of up to 6.79% was achieved. The moth-eye structured PMMA film was fabricated by using an anodic aluminum oxide (AAO template which is simple, low-cost and scalable. The nano-pattern of the AAO template was precisely reproduced onto the PMMA film. The photoanode was composed of Titanium dioxide (TiO2 nanoparticles (NPs with a diameter of 25 nm deposited on the fluorine-doped tin oxide (FTO glass substrate and the sensitizer N3. The double AR layer was proved to effectively improve the short-circuit current density (JSC and conversion efficiency from 14.77 to 15.79 mA/cm2 and from 6.26% to 6.79%, respectively.

  2. Fracture toughness of solid oxide fuel cell anode substrates determined by a double-torsion technique

    Science.gov (United States)

    Pećanac, G.; Wei, J.; Malzbender, J.

    2016-09-01

    Planar solid oxide fuel cell anode substrates are exposed to high mechanical loads during assembly, start-up, steady-state operation and thermal cycling. Hence, characterization of mechanical stability of anode substrates under different oxidation states and at relevant temperatures is essential to warrant a reliable operation of solid oxide fuel cells. As a basis for mechanical assessment of brittle supports, two most common anode substrate material variants, NiO-3YSZ and NiO-8YSZ, were analyzed in this study with respect to their fracture toughness at room temperature and at a typical stack operation temperature of 800 °C. The study considered both, oxidized and reduced materials' states, where also an outlook is given on the behavior of the re-oxidized state that might be induced by malfunctions of sealants or other functional components. Aiming at the improvement of material's production, different types of warm pressed and tape cast NiO-8YSZ substrates were characterized in oxidized and reduced states. Overall, the results confirmed superior fracture toughness of 3YSZ compared to 8YSZ based composites in the oxidized state, whereas in the reduced state 3YSZ based composites showed similar fracture toughness at room temperature, but a higher value at 800 °C compared to 8YSZ based composites. Complementary microstructural analysis aided the interpretation of mechanical characterization.

  3. Characterization of Metal Oxide-Based Gas Nanosensors and Microsensors Fabricated via Local Anodic Oxidation Using Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Bráulio S. Archanjo

    2013-01-01

    Full Text Available This work reports on nanoscale and microscale metal oxide gas sensors, consisting of metal-semiconductor-metal barriers designed via scanning probe microscopy. Two distinct metal oxides, molybdenum and titanium oxides, were tested at different temperatures using CO2 and H2 as test gases. Sensitivities down to ppm levels are demonstrated, and the influence of dry and humid working atmospheres on these metal oxide conductivities was studied. Furthermore, the activation energy was evaluated and analyzed within working sensor temperature range. Finally, full morphological, chemical, and structural analyses of the oxides composites are provided allowing their identification as MoO3 and Ti.

  4. Bimodal spatial distribution of pores in anodically oxidized aluminum thin films

    Science.gov (United States)

    Behnke, J. F.; Sands, T.

    2000-12-01

    Though porous anodic aluminum oxide has been the subject of considerable research since the 1950s, little attention has been devoted to the characterization of the self-organization of the pore structures, and fewer of these studies have focused on anodization of thin films. The degree to which these structures self-organize, however, could play a vital role in future applications of porous anodic aluminum oxide. In this study a model is developed to describe pore ordering in thin anodized aluminum films. The model is based on a radial distribution function approach to describe the interpore spacings. Idealized one-dimensional and two-dimensional (2D) radial distribution functions are combined by linear superposition to approximate experimental radial distribution functions. Using these radial distribution functions, an order parameter is developed and an improved definition of pore spacing is constructed. This method confirms that the oxide initially forms with a highly frustrated porous structure and reorganizes toward greater 2D order as the oxide grows into the film.

  5. The Effect of Anodic Surface Treatment on the Oxidation of Catechols at Ultrasmall Carbon Ring Electrodes

    Science.gov (United States)

    1991-07-09

    selectivity. A model of the surface formed following anodic oxidation is consistent with previous models involving both surface cleanliness and carbon...involving both surface cleanliness and carbon structure orientation. 2 INTRODUCTION Because of the vast electroanalytical utility of carbon electrodes...of the electron transfer rate following treatment are a function of the surface cleanliness and the orientation of the carbon structure

  6. Bacterial nanometric amorphous Fe-based oxide: a potential lithium-ion battery anode material.

    Science.gov (United States)

    Hashimoto, Hideki; Kobayashi, Genki; Sakuma, Ryo; Fujii, Tatsuo; Hayashi, Naoaki; Suzuki, Tomoko; Kanno, Ryoji; Takano, Mikio; Takada, Jun

    2014-04-23

    Amorphous Fe(3+)-based oxide nanoparticles produced by Leptothrix ochracea, aquatic bacteria living worldwide, show a potential as an Fe(3+)/Fe(0) conversion anode material for lithium-ion batteries. The presence of minor components, Si and P, in the original nanoparticles leads to a specific electrode architecture with Fe-based electrochemical centers embedded in a Si, P-based amorphous matrix.

  7. Electrically conducting polymer nanostructures confined in anodized aluminum oxide templates (AAO)

    National Research Council Canada - National Science Library

    Blaszczyk-Lezak, I; Desmaret, V; Mijangos, C

    2016-01-01

    ...) as representative of intrinsically and extrinsically conducting polymers, respectively. In this work, porous anodic aluminum oxide (AAO) templates have been used both as a nanoreactor to synthesize 1D PANI nanostructures by polymerization of the ANI monomer and as a nanomold to prepare 1D PVDF-MWCNT nanorods by melt infiltration of the precursor...

  8. High-performance anode-supported solid oxide fuel cell with impregnated electrodes

    Science.gov (United States)

    Osinkin, D. A.; Bogdanovich, N. M.; Beresnev, S. M.; Zhuravlev, V. D.

    2015-08-01

    The 61%NiO + 39%Zr0.84Y0.16O1.92 (NiO-YSZ) and 56%NiO + 44%Zr0.83Sc0.16Ce0.01O1.92 (NiO-CeSSZ) composite powders have been prepared using two-steps and one-step combustion synthesis, respectively. The Ni-YSZ anode substrate with a low level of electrical resistance (less than 1 mOhm cm) and porosity of about 53% in the reduced state was fabricated. The functional layer of the anode with the high level of electrochemical activity was made of NiO-CeSSZ. The single anode-supported solid oxide fuel cell with the bi-layer Ni-cermet anode, Zr0.84Sc0.16O1.92 film electrolyte and the Pt + 3% Zr0.84Y0.16O1.92 cathode was fabricated. The power density and the U-I curves of the fuel cell at initial state and after impregnation of the cathode and anode by praseodymium and cerium oxides, respectively, have been measured at different temperatures. The maximum of power density of the initial fuel cell was 0.35 W cm-2 at conditions of wet hydrogen (air) supply to the anode (cathode) at 900 °C. After the electrodes were impregnated, the value of power density increased by seven times and was approximately 2.4 W cm-2 at 0.6 V. It was suggested that after the electrodes impregnation the polarization resistance of the fuel cell was determined by the gas diffusion in the supported anode.

  9. Simple solution-processed titanium oxide electron transport layer for efficient inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Institute of Hybrid Materials, Laboratory of New Fiber Materials and Modern Textile—The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Wang, Ning; Dou, Xiaowei; Han, Liangliang; Wen, Shuguang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2014-12-31

    Titanium oxide (TiO{sub X}) is an effective electron transport layer (ETL) in polymer solar cells (PSCs). We report efficient inverted PSCs with a simple solution-processed amorphous TiO{sub X} (s-TiO{sub X}) film as an ETL. The s-TiO{sub X} film with high light transmittance was prepared by spin-coating titanium (IV) isopropoxide isopropanol solution on indium tin oxide coated glass in inert and then placed in air under room temperature for 60 min. The introduction of s-TiO{sub X} ETL greatly improved the short circuit current density of the devices. PSCs based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester and poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′]dithiophene-alt-alkylcarbonyl -thieno[3,4-b]thiophene):[6,6]-phenyl- C71-butyric acid methyl ester using s-TiO{sub X} film as ETL shows high power conversion efficiency of 4.29% and 6.7% under the illumination of AM 1.5G, 100 mW/cm{sup 2}, which shows enhancements compared to the conventional PSCs with poly(styrenesulfonate)-doped poly(ethylenedioxythiophene) as anode buffer layer. In addition, the device exhibits good stability in a humid ambient atmosphere without capsulation. The results indicate that the annealing-free, simple solution processed s-TiO{sub X} film is an efficient ETL for high-performance PSCs. - Highlights: • High quality s-TiO{sub X} films were prepared by a simple, solution method without thermal treatment. • The s-TiO{sub X} films with high transmittance are very smooth. • The organic photovoltaic performance with s-TiO{sub X} film improved greatly and exhibited good stability. • The annealing-free, simple prepared s-TiO{sub X} film will be much compatible with flexible substrates.

  10. Photodegradation of organic pollutants using N-titanium oxide catalyst.

    Science.gov (United States)

    Shinde, S S; Bhosale, C H; Rajpure, K Y

    2014-12-01

    Photoelectrocatalytic degradation of typical aromatic compounds with persistent reaction rate is studied using thin layers of N-titanium dioxide deposited on transparent and conducting glass substrates. Backside illuminated flow-through parallel plate photoelectrochemical reactors is used and electrical bias for suppressing charge carrier recombination is applied externally. The degradation experiments are performed under solar irradiation with the conditions aimed at reducing contaminant concentrations to maximal tolerated levels as specified under environmental regulations. From the observed COD-time relations, rate constants normalized to unit volume and photocurrent (kinetic parameters), characterizing the efficiency of the electrochemical oxidation process involving photogenerated valence band holes or their immediate reaction products, are calculated and compared to the decrease of optical extinction of the solutions. The parameters for salicylic acid, 4-chlorophenol, benzoic acid and oxalic acid are found to decrease as the main absorption peaks of these substances diminish in due course of degradation reaction. In order to realize a complete mineralization of such compounds, which should be an ultimate aim of water purification, COD and TOC is analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Rapid Deposition of Titanium Oxide and Zinc Oxide Films by Solution Precursor Plasma Spray

    Science.gov (United States)

    Ando, Yasutaka

    In order to develop a high rate atmospheric film deposition process for functional films, as a basic study, deposition of titanium oxide film and zinc oxide film by solution precursor plasma spray (SPPS) was conducted in open air. Consequently, in the case of titanium oxide film deposition, anantase film and amorphous film as well as rutile film could be deposited by varying the deposition distance. In the case of anatase dominant film, photo-catalytic properties of the films could be confirmed by wettability test. In addition, the dye sensitized sollar cell (DSC) using the TiO2 film deposited by this SPPS technique as photo voltaic device generates 49mV in OCV. On the other hand, in the case of zinc oxide film deposition, it was proved that well crystallized ZnO films with photo catalytic properties could be deposited. From these results, this process was found to have high potential for high rate functional film deposition process conducted in the air.

  12. Anodic oxidation of oxytetracycline: Influence of the experimental conditions on the degradation rate and mechanism

    Directory of Open Access Journals (Sweden)

    Annabel Fernandes

    2014-12-01

    Full Text Available The anodic oxidation of oxytetracycline was performed with success using as anode a boron-doped diamond electrode. The experiments were conducted in batch mode, using two different electrochemical cells: an up-flow cell, with recirculation, that was used to evaluate the influence of recirculation flow rate; and a stirred cell, used to determine the influence of the applied current density. Besides oxytetracyclin electrodegradation rate and mineralization extent, oxidation by-products were also assessed. Both the flow rate and the applied current density have shown positive influence on the oxytetracycline oxidation rate. On the other hand, the mineralization degree presented the highest values at the lowest flow rate and the lowest current density tested. The main oxidation by-products detected were oxalic, oxamic and maleic acids.

  13. Shadow-casted ultrathin surface coatings of titanium and titanium/silicon oxide sol particles via ultrasound-assisted deposition.

    Science.gov (United States)

    Karahan, H Enis; Birer, Özgür; Karakuş, Kerem; Yıldırım, Cansu

    2016-07-01

    Ultrasound-assisted deposition (USAD) of sol nanoparticles enables the formation of uniform and inherently stable thin films. However, the technique still suffers in coating hard substrates and the use of fast-reacting sol-gel precursors still remains challenging. Here, we report on the deposition of ultrathin titanium and titanium/silicon hybrid oxide coatings using hydroxylated silicon wafers as a model hard substrate. We use acetic acid as the catalyst which also suppresses the reactivity of titanium tetraisopropoxide while increasing the reactivity of tetraethyl orthosilicate through chemical modifications. Taking the advantage of this peculiar behavior, we successfully prepared titanium and titanium/silicon hybrid oxide coatings by USAD. Varying the amount of acetic acid in the reaction media, we managed to modulate thickness and surface roughness of the coatings in nanoscale. Field-emission scanning electron microscopy and atomic force microscopy studies showed the formation of conformal coatings having nanoroughness. Quantitative chemical state maps obtained by x-ray photoelectron spectroscopy (XPS) suggested the formation of ultrathin (coatings and thickness measurements by rotating analyzer ellipsometry supported this observation. For the first time, XPS chemical maps revealed the transport effect of ultrasonic waves since coatings were directly cast on rectangular substrates as circular shadows of the horn with clear thickness gradient from the center to the edges. In addition to the progress made in coating hard substrates, employing fast-reacting precursors and achieving hybrid coatings; this report provides the first visual evidence on previously suggested "acceleration and smashing" mechanism as the main driving force of USAD.

  14. Physical Properties of Mixed Conductor Solid Oxide Fuel Cell Anodes of Doped CeO2

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Lindegaard, Thomas; Hansen, Uffe Rud

    1994-01-01

    Samples of CeO2 doped with oxides such as CaO and Gd2O3 were prepared. Their conductivities and expansions onreduction were measured at 1000°C, and the thermal expansion coefficients in the range 50 to 1000°C were determined. Theionic and electronic conductivity were derived from curves of total...... for solid oxide fuel cell anodes. Not all requirements are fulfilled. Measures to compensate for this arediscussed....

  15. Self-organized nanotubular oxide layers on Ti-6Al-7Nb and Ti-6Al-4V formed by anodization in NH4F solutions.

    Science.gov (United States)

    Macak, Jan M; Tsuchiya, Hiroaki; Taveira, Luciano; Ghicov, Andrei; Schmuki, Patrik

    2005-12-15

    The present work reports the fabrication of self-organized porous oxide-nanotube layers on the biomedical titanium alloys Ti-6Al-7Nb and Ti-6Al-4V by a simple electrochemical treatment. These two-phase alloys were anodized in 1M (NH(4))(2)SO(4) electrolytes containing 0.5 wt % of NH(4)F. The results show that under specific anodization conditions self-organized porous oxide structures can be grown on the alloy surface. SEM images revealed that the porous layers consist of arrays of single nanotubes with a diameter of 100 nm and a spacing of 150 nm. For the V-containing alloy enhanced etching of the beta phase is observed, leading to selective dissolution and an inhomogeneous pore formation. For the Nb-containing alloy an almost ideal coverage of both phases is obtained. According to XPS measurements the tubes are a mixed oxide with an almost stoichiometric oxide composition, and can be grown to thicknesses of several hundreds of nanometers. These findings represent a simple surface treatment for Ti alloys that has high potential for biomedical applications.

  16. Effects of the Use of Pore Formers on Performance of an Anode supported Solid Oxide Fuel Cell

    Energy Technology Data Exchange (ETDEWEB)

    Haslam, J J; Pham, A; Chung, B W; DiCarlo, J F; Glass, R S

    2003-12-04

    The effects of amount of pore former used to produce porosity in the anode of an anode supported planar solid oxide fuel cell were examined. The pore forming material utilized was rice starch. The reduction rate of the anode material was measured by Thermogravimetric Analysis (TGA) to qualitatively characterize the gas transport within the porous anode materials. Fuel cells with varying amounts of porosity produced by using rice starch as a pore former were tested. The performance of the fuel cell was the greatest with an optimum amount of pore former used to create porosity in the anode. This optimum is believed to be related to a trade off between increasing gas diffusion to the active three-phase boundary region of the anode and the loss of performance due to the replacement of active three-phase boundary regions of the anode with porosity.

  17. Synthesis and characterization of nanoporous anodic oxide film on aluminum in H3PO4 + KMnO4 electrolyte mixture at different anodization conditions

    Science.gov (United States)

    Verma, Naveen; Jindal, Jitender; Singh, Krishan Chander; Mari, Bernabe

    2016-04-01

    The micro structural properties of nanoporous anodic oxide film formed in H3PO4 were highly influenced by addition of a low concentration of KMnO4 (0.0005 M) in 1 M H3PO4 solution. The KMnO4 as additive enhanced the growth rate of oxide film formation as well as thickness of pore walls. Furthermore the growth rate was found increased with increase in applied current density. The increase in temperature and lack of stirring during anodization causes the thinness of pore wall which leads to increase in pore volume. With the decrease in concentration of H3PO4 in anodizing electrolyte from 1M to 0.3 M, keeping all other conditions constant, the decrease in porosity was observed. This might be due to the dissolution of aluminium oxide film in highly concentrated acidic solution.

  18. Anodic oxidation of o-nitrophenol on BDD electrode: Variable effects and mechanisms of degradation

    Energy Technology Data Exchange (ETDEWEB)

    Rabaaoui, Nejmeddine, E-mail: chimie_tunisie@yahoo.fr [Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa (Tunisia); Saad, Mohamed El Khames [Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa (Tunisia); Moussaoui, Younes [Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa (Tunisia); Physical Organic Chemistry Laboratory, Science Faculty of Sfax, University of Sfax (Tunisia); Allagui, Mohamed Salah [Science Faculty of Gafsa, University of Gafsa (Tunisia); Bedoui, Ahmed [Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa (Tunisia); Science Faculty of Gabes, 6072, University of Gabes (Tunisia); Elaloui, Elimame [Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa (Tunisia); Science Faculty of Gafsa, University of Gafsa (Tunisia)

    2013-04-15

    Highlights: ► Anodic oxidation is an effective method for degrading o-nitrophenol. ► The effect of operating parameters on the degradation was investigated. ► The main intermediate products were determined by HPLC technique. ► A plausible degradation pathway of o-nitrophenol was proposed. -- Abstract: The electrochemical oxidation of pesticide, o-nitrophenol (ONP) as one kind of pesticide that is potentially dangerous and biorefractory, was studied by galvanostatic electrolysis using boron-doped diamond (BDD) as anode. The influence of several operating parameters, such as applied current density, supporting electrolyte, and initial pH value, was investigated. The best degradation occurred in the presence of Na{sub 2}SO{sub 4} (0.05 M) as conductive electrolyte. After 8 h, nearly complete degradation of o-nitrophenol was achieved (92%) using BDD electrodes at pH 3 and at current density equals 60 mA cm{sup −2}. The decay kinetics of o-nitrophenol follows a pseudo-first-order reaction. Aromatic intermediates such as catechol, resorcinol, 1,2,4-trihydroxybenzene, hydroquinone and benzoquinone and carboxylic acids such as maleic glycolic, malonic, glyoxilic and oxalic, have been identified and followed during the ONP treatment by chromatographic techniques. From these anodic oxidation by-products, a plausible reaction sequence for ONP mineralization on BDD anodes is proposed.

  19. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior.

    Science.gov (United States)

    Beltrán-Partida, Ernesto; Valdez-Salas, Benjamín; Escamilla, Alan; Curiel, Mario; Valdez-Salas, Ernesto; Nedev, Nicola; Bastidas, Jose M

    2016-03-01

    Amorphous titanium dioxide (TiO2) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability.

  20. Effect of impregnation phases on the performance of Ni-based anodes for low temperature solid oxide fuel cells

    Science.gov (United States)

    Liu, Zhangbo; Ding, Dong; Liu, Beibei; Guo, Weiwei; Wang, Wendong; Xia, Changrong

    2011-10-01

    Impregnated nanoparticles are very effective in improving the electrochemical performance of solid oxide fuel cell (SOFC) anodes possibly due to the extension of reaction sites and/or the enhancement of catalytic activity. In this work, samaria-doped ceria (SDC), pure ceria, samaria, and alumina oxides impregnated Ni-based anodes are fabricated to compare the site extending and the catalytic effects. Except for alumina, the impregnation of the other three nano-sized oxides could substantially enhance the performance of the anodes for the hydrogen oxidation reactions. Moreover, single cells with CeO2 and Sm2O3 impregnated anodes could exhibit as great performance as those with SDC impregnated anodes. When the impregnation loading reached the optimal value, 1.7 mmol cm-3, these cells exhibit very high performance, with peak power densities around 750 mW cm-2. The high performance of CeO2 and Sm2O3 impregnated anodes demonstrates that the improved performance are mainly attributed to the significantly improved electrochemical activities of the anodes, but not to the extension of triple-phase-boundary, and wet impregnation is indeed an alternative and effective technique to introduce these nano-sized catalytic active oxides into the anode configuration of SOFCs to enhance cell performance, stability and reliability.

  1. Fabrication of Crystalline Indium Tin Oxide Nanobasket Electrodes using Aluminum Anodic Oxide Template

    Science.gov (United States)

    Wang, Gou-Jen; Chen, He-Tsing; Yang, Hsihang

    2008-07-01

    Fabrication of crystalline indium tin oxide (ITO) nanobasket electrodes shaped by an anodic aluminum oxide (AAO) template for better electron conductivity is presented. ITO films were deposited on porous AAO templates by RF magnetron sputtering. The sputter-coated ITO films were characterized by field-emission scanning electron microscopy (FESEM) to illustrate the nanobasket morphologies. The compositions of the ITO films were characterized by energy-dispersive X-ray (EDS) analysis. X-ray diffraction (XRD) analysis was conducted to evaluate the crystallinity. The crystallinity can be enhanced by annealing at 300 °C. Although the conductivity of the ITO nanobasket film is larger than that of the conventional ITO thin film, the harvest efficiency can be markedly increased due to the nanobasket structure which enables most of the photoexcited electrons to reach their nearest electrode before losing their momentum. The presented ITO nanobasket films can be further used as a more effective electrode material for photovoltaics such as dye-sensitized solar cells (DSSCs).

  2. Binder-free graphene and manganese oxide coated carbon felt anode for high-performance microbial fuel cell.

    Science.gov (United States)

    Zhang, Changyong; Liang, Peng; Yang, Xufei; Jiang, Yong; Bian, Yanhong; Chen, Chengmeng; Zhang, Xiaoyuan; Huang, Xia

    2016-07-15

    A novel anode was developed by coating reduced graphene oxide (rGO) and manganese oxide (MnO2) composite on the carbon felt (CF) surface. With a large surface area and excellent electrical conductivity, this binder-free anode was found to effectively enhance the enrichment and growth of electrochemically active bacteria and facilitate the extracellular electron transfer from the bacteria to the anode. A microbial fuel cell (MFC) equipped with the rGO/MnO2/CF anode delivered a maximum power density of 2065mWm(-2), 154% higher than that with a bare CF anode. The internal resistance of the MFC with this novel anode was 79Ω, 66% lower than the regular one's (234Ω). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses affirmed that the rGO/MnO2 composite significantly increased the anodic reaction rates and facilitated the electron transfer from the bacteria to the anode. The findings from this study suggest that the rGO/MnO2/CF anode, fabricated via a simple dip-coating and electro-deposition process, could be a promising anode material for high-performance MFC applications.

  3. Oxide-bioceramic coatings obtained on titanium items by the induction heat treatment and modified with hydroxyapatite nanoparticles

    Science.gov (United States)

    Fomin, Aleksandr A.; Fomina, Marina A.; Rodionov, Igor V.; Koshuro, Vladimir A.; Petrova, Natalia V.; Skaptsov, Aleksandr A.; Atkin, Vsevolod S.

    2015-06-01

    Prospective composite bioceramic titania coatings were obtained on intraosseous implants fabricated from cp-titanium and medical titanium alloy VT16 (Ti-2.5Al-5Mo-5V). Consistency changes of morphological characteristics, mechanical properties and biocompatibility of experimental titanium implant coatings obtained by oxidation during induction heat treatment are defined. Technological recommendations for obtaining bioceramic coatings with extremely high strength on titanium items surface are given.

  4. Cerium-modified doped strontium titanate compositions for solid oxide fuel cell anodes and electrodes for other electrochemical devices

    Science.gov (United States)

    Marina, Olga A [Richland, WA; Stevenson, Jeffry W [Richland, WA

    2010-03-02

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells and electrochemical devices such as solid oxide fuel cells, electrolyzers, sensors, pumps and the like, the compositions comprising cerium-modified doped strontium titanate. The invention also provides novel methods for making and using anode material compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having anodes comprising the compositions.

  5. Assessment of the performance of Ni-yttria-stabilized zirconia anodes in anode-supported Solid Oxide Fuel Cells operating on H 2-CO syngas fuels

    Science.gov (United States)

    Ye, Xiao-Feng; Wang, S. R.; Zhou, J.; Zeng, F. R.; Nie, H. W.; Wen, T. L.

    Anode-supported Solid Oxide Fuel Cells (SOFCs) with Ni-yttria-stabilized zirconia (YSZ) anode have been fabricated and studied using H 2-CO syngas fuels. Syngas fuels with different compositions of H 2-CO are supplied and the cell performance is measured at 750 °C. A high CO content has caused carbon deposition and crack formation in the Ni-YSZ anode after long-term operation, even though it is diluted with H 2O and N 2. However, it was found that a Cu-CeO 2 coating on Ni-YSZ can greatly improve the anode stability in syngas by facilitating the water gas shift reaction. The optimized single cell has run in sygas with a composition of 65%H 2-32%CO-3%H 2O for 1050 h without obvious degradation of its performance.

  6. New roots to formation of nanostructures on glass surface through anodic oxidation of sputtered aluminum

    Directory of Open Access Journals (Sweden)

    Satoru Inoue, Song-Zhu Chu, Kenji Wada, Di Li and Hajime Haneda

    2003-01-01

    Full Text Available New processes for the preparation of nanostructure on glass surfaces have been developed through anodic oxidation of sputtered aluminum. Aluminum thin film sputtered on a tin doped indium oxide (ITO thin film on a glass surface was converted into alumina by anodic oxidation. The anodic alumina gave nanometer size pore array standing vertically on the glass surface. Kinds of acids used in the anodic oxidation changed the pore size drastically. The employment of phosphoric acid solution gave several tens nanometer size pores. Oxalic acid cases produced a few tens nanometer size pores and sulfuric acid solution provided a few nanometer size pores. The number of pores in a unit area could be changed with varying the applied voltage in the anodization and the pore sizes could be increased by phosphoric acid etching. The specimen consisting of a glass substrate with the alumina nanostructures on the surface could transmit UV and visible light. An etched specimen was dipped in a TiO2 sol solution, resulting in the impregnation of TiO2 sol into the pores of alumina layer. The TiO2 sol was heated at ~400 °C for 2 h, converting into anatase phase TiO2. The specimens possessing TiO2 film on the pore wall were transparent to the light in UV–Visible region. The electro deposition technique was applied to the introduction of Ni metal into pores, giving Ni nanorod array on the glass surface. The removal of the barrier layer alumina at the bottom of the pores was necessary to attain smooth electro deposition of Ni. The photo catalytic function of the specimens possessing TiO2 nanotube array was investigated in the decomposition of acetaldehyde gas under the irradiation of UV light, showing that the rate of the decomposition was quite large.

  7. Electrospun carbon-tin oxide composite nanofibers for use as lithium ion battery anodes.

    Science.gov (United States)

    Bonino, Christopher A; Ji, Liwen; Lin, Zhan; Toprakci, Ozan; Zhang, Xiangwu; Khan, Saad A

    2011-07-01

    Composite carbon-tin oxide (C-SnO(2)) nanofibers are prepared by two methods and evaluated as anodes in lithium-ion battery half cells. Such an approach complements the long cycle life of carbon with the high lithium storage capacity of tin oxide. In addition, the high surface-to-volume ratio of the nanofibers improves the accessibility for lithium intercalation as compared to graphite-based anodes, while eliminating the need for binders or conductive additives. The composite nanofibrous anodes have first discharge capacities of 788 mAh g(-1) at 50 mA g(-1) current density, which are greater than pure carbon nanofiber anodes, as well as the theoretical capacity of graphite (372 mAh g(-1)), the traditional anode material. In the first protocol to fabricate the C-SnO(2) composites, tin sulfate is directly incorporated within polyacrylonitrile (PAN) nanofibers by electrospinning. During a thermal treatment the tin salt is converted to tin oxide and the polymer is carbonized, yielding carbon-SnO(2) nanofibers. In the second approach, we soak the nanofiber mats in tin sulfate solutions prior to the final thermal treatment, thereby loading the outer surfaces with SnO(2) nanoparticles and raising the tin content from 1.9 to 8.6 wt %. Energy-dispersive spectroscopy and X-ray diffraction analyses confirm the formation of conversion of tin sulfate to tin oxide. Furthermore, analysis with Raman spectroscopy reveals that the additional salt soak treatment from the second fabrication approach increases in the disorder of the carbon structure, as compared to the first approach. We also discuss the performance of our C-SnO(2) compared with its theoretical capacity and other nanofiber electrode composites previously reported in the literature.

  8. The effect of different oxide layers on the sensing properties of anodic alumina nanoporous film

    Directory of Open Access Journals (Sweden)

    H. Abbasian

    2014-03-01

    Full Text Available In the present work, anodized aluminum oxide template was prepared by accelerated mild anodization technique in 0.6M phosphoric aside and 175 V, anodization voltage. Pore widening was performed by chemical etching in 0.5M phosphoric acid for 8, 16, 32, 40 minutes. Scanning Electron Microscopy (SEM images showed the pores, diameter exponentially increases with etching time. By depositing silver contacts on the prepared samples and using an RC circuit for applying impedance spectroscopy, the characteristics of the humidity sensor based on constructed samples were investigated. The maximum response was seen for the sample etched for 40 minutes. For this sample, the detectable threshold of relative moisture was 30% and the response and the recovery time were 8, 2 seconds, respectively

  9. Model of porous aluminium oxide growth during initial stage of anodization

    Science.gov (United States)

    Aryslanova, E. M.; Alfimov, A. V.; Chivilikhin, S. A.

    2014-10-01

    Currently, the development of nanotechnology and metamaterials requires the ability to obtain regular self-assembled structures with different parameters. One such structure is porous alumina in which the pores grow perpendicular to the substrate and are hexagonally packed. Pore size and the distance between them can be varied depending on the anodization voltage, the electrolyte and the anodization time (pore diameter - from 2 to 350 nm, the distance between the pores - from 5 to 50 nm). At the moment, there are different models describing the process of anodizing aluminum, in this paper we propose a model that takes into account the effect of layers of aluminum, aluminum oxide, and the electrolyte, as well as the influence of the effect of surface diffusion.

  10. Reduced Graphene Oxide/Tin-Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries.

    Science.gov (United States)

    Ji, Liwen; Zhou, Weidong; Chabot, Victor; Yu, Aiping; Xiao, Xingcheng

    2015-11-11

    Reduced graphene oxides loaded with tin-antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20-30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g(-1), stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO-based flexible framework and the nanoscale dimension of the SnSb alloy particles (batteries.

  11. Optimization of dry reforming of methane over Ni/YSZ anodes for solid oxide fuel cells

    Science.gov (United States)

    Guerra, Cosimo; Lanzini, Andrea; Leone, Pierluigi; Santarelli, Massimo; Brandon, Nigel P.

    2014-01-01

    This work investigates the catalytic properties of Ni/YSZ anodes as electrodes of Solid Oxide Fuel Cells (SOFCs) to be operated under direct dry reforming of methane. The experimental test rig consists of a micro-reactor, where anode samples are characterized. The gas composition at the reactor outlet is monitored using a mass spectrometer. The kinetics of the reactions occurring over the anode is investigated by means of Isotherm reactions and Temperature-programmed reactions. The effect of the variation of temperature, gas residence time and inlet carbon dioxide-methane volumetric ratio is analyzed. At 800 °C, the best catalytic performance (in the carbon safe region) is obtained for 1.5 dry reforming and cracking reactions, respectively. In other ranges, dry reforming and reverse water gas shift are the dominant reactions and the inlet feed reaches almost the equilibrium condition provided that a sufficient gas residence time is obtained.

  12. Biogas Catalytic Reforming Studies on Nickel-Based Solid Oxide Fuel Cell Anodes

    DEFF Research Database (Denmark)

    Johnson, Gregory B.; Hjalmarsson, Per; Norrman, Kion;

    2016-01-01

    Heterogeneous catalysis studies were conducted on two crushed solid oxide fuel cell (SOFC) anodes in fixed-bed reactors. The baseline anode was Ni/ScYSZ (Ni/scandia and yttria stabilized zirconia), the other was Ni/ScYSZ modified with Pd/doped ceria (Ni/ScYSZ/Pd-CGO). Three main types...... of Pd-CGO helped to mitigate sulfur deactivation effect; e.g. lowering the onset temperature (up to 190°C) for CH4 conversion during temperature-programmed reactions. Both Ni/ScYSZ and Ni/ScYSZ/Pd-CGO anode catalysts were more active for dry reforming of biogas than they were for steam reforming....... Deactivation of reforming activity by sulfur was much more severe under steam reforming conditions than dry reforming; a result of greater sulfur retention on the catalyst surface during steam reforming....

  13. In situ luminescence and IR study of porous silicon during and after anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Dubin, V.M. [Laboratoire de Physique de la Matiere Condensee, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Ozanam, F. [Laboratoire de Physique de la Matiere Condensee, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Chazalviel, J.N. [Laboratoire de Physique de la Matiere Condensee, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex (France)

    1995-01-15

    When porous silicon is transferred into a non-fluoride electrolyte and anodically oxidized, the onset of red electroluminescence during anodic oxidation appears correlated with a decrease in the OH IR absorption bands, indicating significant electrolyte removal from the pores. The electron states whose population is affected by carrier injection or light excitation have been investigated using in situ electromodulated or photomodulated IR spectroscopy. The modulated IR absorption of red-luminescent electro-oxidized porous silicon exhibits an extra absorption of localized carriers in the 1000-2500cm{sup -1} region, suggesting that the red luminescence occurs through carriers trapped in localized states. The localization process may be efficiently affected by the dielectric constant of the medium surrounding the silicon nanocrystallites. ((orig.))

  14. Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying

    DEFF Research Database (Denmark)

    Canulescu, Stela; Rechendorff, K.; Borca, C. N.

    2014-01-01

    are not located in a TiO2 unit in the oxide layer, but rather in a mixed Ti-Al oxide layer. The optical band gap energy of the anodic oxide layers was determined by vacuum ultraviolet spectroscopy in the energy range from 4.1 to 9.2 eV (300–135 nm). The results indicate that amorphous anodic Al2O3 has a direct...... band gap of 7.3 eV, which is about ∼1.4 eV lower than its crystalline counterpart (single-crystal Al2O3). Upon Ti-alloying, extra bands appear within the band gap of amorphous Al2O3, mainly caused by Ti 3d orbitals localized at the Ti site....

  15. Mineralization of bisphenol A (BPA) by anodic oxidation with boron-doped diamond (BDD) electrode.

    Science.gov (United States)

    Murugananthan, M; Yoshihara, S; Rakuma, T; Shirakashi, T

    2008-06-15

    Anodic oxidation of bisphenol A (BPA), a representative endocrine disrupting chemical, was carried out using boron-doped diamond (BDD) electrode at galvanostatic mode. The electro-oxidation behavior of BPA at BDD electrode was investigated by means of cyclic voltammetric technique. The extent of degradation and mineralization of BPA were monitored by HPLC and total organic carbon (TOC) value, respectively. The results obtained, indicate that the BPA removal at BDD depends on the applied current density (Iappl), initial concentration of BPA, pH of electrolyte and supporting medium. Galvanostatic electrolysis at BDD anode cause concomitant generation of hydroxyl radical that leads to the BPA destruction. The kinetics for the BPA degradation follows a pseudo-first order reaction with a higher rate constant 12.8x10(-5) s(-1) for higher Iappl value 35.7 mA cm(-2), indicating that the oxidation reaction is limited by Iappl control. Complete mineralization of BPA was achieved regardless of the variables and accordingly the mineralization current efficiency was calculated from the TOC removal measurements. Considering global oxidation process, the effect of supporting electrolytes has been discussed in terms of the electro generated inorganic oxidants. The better performance of BDD anode was proved on a comparative study with Pt and glassy carbon under similar experimental conditions. A possible reaction mechanism for BPA degradation involving three main aromatic intermediates, identified by GC-MS analysis, was proposed.

  16. Investigations into the interactions between sulfur and anodes for solid oxide fuel cells

    Science.gov (United States)

    Cheng, Zhe

    Solid oxide fuel cells (SOFCs) are electrochemical devices based on solid oxide electrolytes that convert chemical energy in fuels directly into electricity via electrode reactions. SOFCs have the advantages of high energy efficiency and low emissions and hold the potential to be the power of the future especially for small power generation systems (1-10 kW). Another unique advantage of SOFCs is the potential to directly utilize hydrocarbon fuels such as natural gas through internal reforming. However, all hydrocarbon fuels contain some sulfur compounds, which transform to hydrogen sulfide (H2S) in the reforming process and dramatically degrade the performance of the existing SOFCs. In this study, the interactions between sulfur contaminant (in the form of H2S) and the anodes for SOFCs were systematically investigated in order to gain a fundamental understanding of the mechanism of sulfur poisoning and ultimately to achieve rational design of sulfur-tolerant anodes. The sulfur poisoning behavior of the state-of-the-art Ni-YSZ cermet anodes was characterized using electrochemical measurements performed on button cells (of different structures) under various operating conditions, including H2S concentration, temperature, cell current density/terminal voltage, and cell structure. Also, the mechanisms of interactions between sulfur and the Ni-YSZ cermet anode were investigated using both ex situ and in situ characterization techniques such as Raman spectroscopy. Results suggest that the sulfur poisoning of Ni-YSZ cermet anodes at high temperatures in fuels with ppm-level H2S is due not to the formation of multi-layer conventional nickel sulfides but to the adsorption of sulfur on the nickel surface. In addition, new sulfur-tolerant anode materials were explored in this study. Thermodynamic principles were applied to predict the stability of candidate sulfur-tolerant anode materials and explain complex phenomena concerning the reactivity of candidate materials with

  17. Plasma Niobium Surface Alloying of Pure Titanium and its Oxidation at 900 ℃

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-bo; ZHONG Xu; HE Zhi-yong; WANG Zhen-xia; ZHANG Ping-ze

    2007-01-01

    A niobium-modified layer on pure titanium surface was obtained by means of double glow plasma surface alloying technique. The modified layer was uniform, continuous, compact and well adhered to the substrate. The niobium composition in the modified layer decreased gradually from the surface to the substrate. The oxidation behavior of the niobium-modified layer was investigated and compared with the untreated surface at 900 ℃ for 100 h. Characterization of the layers was performed using X-ray diffraction and scanning electron microscope, respectively. The test results show that the oxidation behavior of pure titanium was improved by niobium alloying process. Niobium has a positive influence on the oxidation resistance.

  18. Layered reduced graphene oxide with nanoscale interlayer gaps as a stable host for lithium metal anodes

    Science.gov (United States)

    Lin, Dingchang; Liu, Yayuan; Liang, Zheng; Lee, Hyun-Wook; Sun, Jie; Wang, Haotian; Yan, Kai; Xie, Jin; Cui, Yi

    2016-07-01

    Metallic lithium is a promising anode candidate for future high-energy-density lithium batteries. It is a light-weight material, and has the highest theoretical capacity (3,860 mAh g-1) and the lowest electrochemical potential of all candidates. There are, however, at least three major hurdles before lithium metal anodes can become a viable technology: uneven and dendritic lithium deposition, unstable solid electrolyte interphase and almost infinite relative dimension change during cycling. Previous research has tackled the first two issues, but the last is still mostly unsolved. Here we report a composite lithium metal anode that exhibits low dimension variation (˜20%) during cycling and good mechanical flexibility. The anode is composed of 7 wt% ‘lithiophilic’ layered reduced graphene oxide with nanoscale gaps that can host metallic lithium. The anode retains up to ˜3,390 mAh g-1 of capacity, exhibits low overpotential (˜80 mV at 3 mA cm-2) and a flat voltage profile in a carbonate electrolyte. A full-cell battery with a LiCoO2 cathode shows good rate capability and flat voltage profiles.

  19. Ceramic Lithium Ion Conductor to Solve the Anode Coking Problem of Practical Solid Oxide Fuel Cells.

    Science.gov (United States)

    Wang, Wei; Wang, Feng; Chen, Yubo; Qu, Jifa; Tadé, Moses O; Shao, Zongping

    2015-09-07

    For practical solid oxide fuel cells (SOFCs) operated on hydrocarbon fuels, the facile coke formation over Ni-based anodes has become a key factor that limits their widespread application. Modification of the anodes with basic elements may effectively improve their coking resistance in the short term; however, the easy loss of basic elements by thermal evaporation at high temperatures is a new emerging problem. Herein, we propose a new design to develop coking-resistant and stable SOFCs using Li(+) -conducting Li0.33 La0.56 TiO3 (LLTO) as an anode component. In the Ni/LLTO composite, any loss of surface lithium can be efficiently compensated by lithium diffused from the LLTO bulk under operation. Therefore, the SOFC with the Ni/LLTO anode catalyst layer yields excellent power outputs and operational stability. Our results suggest that the simple adoption of a Li(+) conductor as a modifier for Ni-based anodes is a practical and easy way to solve the coking problem of SOFCs that operate on hydrocarbons.

  20. Doped titanium oxide photcatalysts: Preparation, structure and interaction with viruses

    Science.gov (United States)

    Li, Qi

    Since the discovery of photoelectrochemical splitting of water on n-titanium oxide (n-TiO2) electrodes by Fujishima and Honda in 1972, there has been much interest in semiconductor-based materials as photocatalysts for both solar energy conversion and environmental applications in the past several decades. Among various semiconductor-based photocatalysts, TiO2 is the only candidate suitable for industrial use because of its high chemical stability, good photoactivity, relatively low cost, and nontoxicity. However, the photocatalytic capability of TiO 2 is limited to only ultraviolet (UV) light (wavelength, lambda, disinfection of bacteria and viruses under visible light illumination. The sol-gel process was optimized to produce high quality TiON-based photocatalysts by carefully modulating the precursor ratio and calcination temperature. A TiON inverse opal structure was created, which demonstrated enhanced visible light absorption and subsequently improved photocatalytic efficiency by the combination of chemical and physical modifications on n-TiO2. The effect of palladium dopant on the optical and photocatalytic properties of TiON/PdO photocatalyst was examined, which suggests that a careful optimization of the transition metal ion dopant concentration is needed to achieve high photocatalytic efficiency in these anion and transition metal ion co-doped TiO2 photocatalysts. High photocatalytic virus disinfection efficiency under visible-light illumination was observed for the first time with TiON/PdO photocatalyst, and the interaction between MS2 virus and TiO2-based semiconductor surfaces was successfully modulated. A strategy to use atomic force microscope (AFM) to conduct in-situ observation of viruses on semiconductor surfaces in aqueous environment was developed, which combines information from both height profile and phase profile and solves the difficulty of observing small nanosized biomolecules on substrates with similar feature sizes.

  1. Analysis of titanium dioxide and zinc oxide nanoparticles in cosmetics

    Directory of Open Access Journals (Sweden)

    Pei-Jia Lu

    2015-09-01

    Full Text Available There have been rapid increases in consumer products containing nanomaterials, raising concerns over the impact of nanoparticles (NPs to humankind and the environment, but little information has been published about mineral filters in commercial sunscreens. It is urgent to develop methods to characterize the nanomaterials in products. Titanium dioxide (TiO2 and zinc oxide (ZnO NPs in unmodified commercial sunscreens were characterized by laser scanning confocal microscopy, atomic force microscopy, X-ray diffraction (XRD, and transmission electron microscopy (TEM. The results showed that laser scanning confocal microscopy evaluated primary particle aggregates and dispersions but could not size NPs because of the diffraction limited resolution of optical microscopy (200 nm. Atomic force microscopy measurements required a pretreatment of the sunscreens or further calibration in phase analysis, but could not provide their elemental composition of commercial sunscreens. While XRD gave particle size and crystal information without a pretreatment of sunscreen, TEM analysis required dilution and dispersion of the commercial sunscreens before imaging. When coupled with energy-dispersive X-ray spectroscopy, TEM afforded particle size information and compositional analysis. XRD characterization of six commercial sunscreens labeled as nanoparticles revealed that three samples contained TiO2 NPs, among which two listed ZnO and TiO2, and displayed average particle sizes of 15 nm, 21 nm, and 78 nm. However, no nanosized ZnO particles were found in any of the samples by XRD. In general, TEM can resolve nanomaterials that exhibit one or more dimensions between 1 nm and 100 nm, allowing the identification of ZnO and TiO2 NPs in all six sunscreens and ZnO/TiO2 mixtures in two of the samples. Overall, the combination of XRD and TEM was suitable for analyzing ZnO and TiO2 NPs in commercial sunscreens.

  2. Improvement of organic solar cell performances using a zinc oxide anode coated by an ultrathin metallic layer

    Science.gov (United States)

    Bernède, J. C.; Berredjem, Y.; Cattin, L.; Morsli, M.

    2008-02-01

    The authors have achieved an efficient organic solar cell based on copper phthalocyanine (CuPc) layer as donor and fullerene (C60) as acceptor. The aluminum doped zinc oxide (ZnO:Al) instead of indium tin oxide (ITO) is used as the anode. An ultrathin gold film is introduced among ZnO:Al, transparent conductor oxide, and the CuPc donor layer. We show that the power conversion efficiency of this cell is enhanced by one order of magnitude compared to that achieved with a ZnO anode without ultrathin gold film. Therefore, the power conversion efficiency of this cell is comparable to that with an ITO anode.

  3. Research progress in titanium dioxide nanotube arrays as three-dimensional anode materials%三维负极材料二氧化钛纳米管阵列的研究进展

    Institute of Scientific and Technical Information of China (English)

    谭晓旭; 唐谊平; 曹华珍; 郑国渠

    2011-01-01

    The synthetic methods of titanium dioxide ( TiO2) nanotube arrays (TNTAs) such as template method and anodic oxidation method were summarized, the effects of TNTAs' structure and modification on the electro chemical performance of the electrode were reviewed. The research directions of TNTAs used as three-dimensional anode material of Li-ion battery, such as surface modification, loading high electric conductivity and high capacity material, developing metastable TiO2(B) nanoarrays with high capacity, were pointed out.%综述了二氧化钛(TiO2)纳米管阵列(TNTAs)的常用制备方法——模板法和阳极氧化法,以及TNTAs结构特征和表面改性对电极电化学性能的影响.指出表面改性,负载高导电率和高容量物质,以及开发高容量的亚稳态晶型TiO2(B)纳米阵列等,是TNTAs作为锂离子电池三维纳米负极材料的研究方向.

  4. Analysis of peel strength of consisting of an aluminum sheet, anodic aluminum oxide and a copper foil laminate composite

    Science.gov (United States)

    Shin, Hyeong-Won; Lee, Hyo-Soo; Jung, Seung-Boo

    2017-01-01

    Laminate composites consisting of an aluminum sheet, anodic aluminum oxide, and copper foil have been used as heat-spreader materials for high-power light-emitting diodes (LEDs). These composites are comparable to the conventional structure comprising an aluminum sheet, epoxy adhesives, and copper foil. The peel strength between the copper foil and anodic aluminum oxide should be more than 1.0 kgf/cm in order to be applied in high-power LED products. We investigated the effect of the anodic aluminum oxide morphology and heat-treatment conditions on the peel strength of the composites. We formed an anodic aluminum oxide layer on a 99.999% pure aluminum sheet using electrochemical anodization. A Ti/Cu seed layer was formed using the sputtering direct bonding copper process in order to form a copper circuit layer on the anodic aluminum oxide layer by electroplating. The developed heat spreader, composed of an aluminum layer, anodic aluminum oxide, and a copper circuit layer, showed peel strengths ranging from 1.05 to 3.45 kgf/cm, which is very suitable for high-power LED applications.

  5. Relationship between the Local Structures of Titanium Oxide Photocatalysts and Their Reactivities in the NO Decomposition

    Institute of Scientific and Technical Information of China (English)

    Jin-Long ZHANG; Masaya MATSUOKA; Hiromi YAMASHITA; Masakazu ANPO

    2000-01-01

    @@ The photocatalysts included titanium oxide were prepared by ion-exchange method and impregnating method, in which zeolites of different Si/Al ratios were used as supporters. Those photocatalysts by an ionexchange method in zeolite of low Si/Al ratio, exhibited high and unique photocatalytic reactivity for the direct decomposition of NO into N2, N2O and O2 at 275K. In situ photoluminescence, diffuse reflectance absorption,XAFS investigations indicated that the titanium oxide species are highly dispersed within the zeolite and exist in tetrahedral coordination when the titanium oxide species anchored in the zeolite of low Si/Al ratio. The charge transfer excited state of the highly dispersed titanium oxide species play a significant role in the decomposition of NO exhibrting a high selectivity for the formation of N2, while the catalysts involving the aggregated octahedrally coordinated titanium oxide species show a high selectivity to produce NiO, being similar to reactions on the powdered TiO2 catalysts.

  6. Large Scale Inert Anode for Molten Oxide Electrolysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Molten oxide electrolysis is a demonstrated laboratory-scale process for producing oxygen from the JSC-1a lunar simulant; however, critical subsystems necessary for...

  7. Effect of hybrid oxidation on the titanium oxide layer's properties investigated by spectroscopic methods

    Science.gov (United States)

    Jasinski, J. J.; Kurpaska, L.; Lubas, M.; Lesniak, M.; Jasinski, J.; Sitarz, M.

    2016-12-01

    In this work the study of hybrid Ti Grade 2 during oxidation using FADT - fluidized bed atmospheric diffusive treatment and PVD - magnetron sputtering have been investigated. Additionally, the influence of the oxidation method on the change in the mechanism of oxygen transport to the substrate have been discussed (phenomenon responsible for the improvement of bioactivity). Presented method consists in forming the titanium surface layer saturated with oxygen due to the diffusion and deposition of a thin homogeneous oxide coating on the Ti surface. Discussed processes diminish the surface roughness and increase bio-compatibility of the surface, which results in easier hydroxyapatite cluster deposition. The diffusion process was conducted on Al2O3 fluidized bed, with air as the fluidizing factor at 913 K for 8 h. The deposition of the oxide coatings were carried out with magnetron sputtering, with the use of a TiO2 target at a pressure of 3 × 10-2 mbars and power of 350 W. To evaluate the effects of hybrid oxidation and to determine the mechanism of oxygen transport, the following research methods have been applied: spectroscopy (GDOS, SIMS, RS), microscopic methods (SEM-EDS, SEM-EBSD, TEM-EFTEM), X-ray tests (μ-XRD, GID). Obtained test results were used to identify the type of oxide coatings, to assess the thickness of the layers and to study the influence of crystallographic orientation on oxygen transport and concentration in the surface layer and in the oxide coating. It has been found that the formation of oxide coatings created by using the hybrid method (FADT + PVD leads to a change in oxygen concentration in the substrate due to introduced defects. This phenomenon is in opposition to the conventional methods such as: electrochemical or laser oxidation. In contrast, forming a tight homogeneous oxide coating on Ti surface improves the biocompatibility, which is particularly important in the context of biomedical applications.

  8. Electrochemical Characteristics of Tin Oxide-Graphite as Anode Material for Lithium-ion Cells

    Science.gov (United States)

    Hasanaly, Siti Munirah

    2010-03-01

    Tin oxide anode materials used in lithium-ion cells experience large volume changes during charging and discharging which cause substantial losses in capacity. In this work, the tin oxide-graphite composite is proposed as an alternative anode material to overcome this problem. The composite was synthesised from a solution of tin chloride dihydrate and graphite powders with citric acid as the chelating agent. In this sol-gel method, a solid phase is formed through a chemical reaction in a liquid phase at moderate temperature. The technique offers several advantages compared to the solid state synthesis technique such as the ability to maintain the homogeneous mixture of precursors during synthesis and to produce small particles. The electrochemical behaviour of the anode material was investigated by means of galvanostatic charge discharge technique. An initial reversible capacity of 748 mAh/g is obtained and nearly 600 mAh/g was retained upon the reaching the fifth cycle. This study shows that the presence of graphite is able to minimise the agglomeration of tin particles that causes large volume changes during cycling, thereby improving cyclability of the anode material.

  9. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    Science.gov (United States)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin; Hjelm, Johan; Bonanos, Nikolaos

    2012-10-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3-δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell, consisting of a Ni-yttria stabilized zirconia (YSZ) anode support, a Ni-scandia-doped yttria-stabilized zirconia (ScYSZ) anode, a ScYSZ electrolyte, and a CGO barrier layer. LSC was introduced into the CGO backbone by multiple infiltrations of an aqueous nitrate solution followed by firing. The cell was tested at 700 °C under a current density of 0.5 A cm-2 for 1500 h using air as oxidant and humidified hydrogen as fuel. The electrochemical performance of the cell was analyzed by impedance spectroscopy and current-voltage relationships. No measurable degradation in the cell voltage or increase in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79 W cm-2 at a cell voltage of 0.6 V at 750 °C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference to that of a nominally identical untested counterpart.

  10. Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode.

    Science.gov (United States)

    Bejankiwar, Rajesh S; Basu, Abir; Cementi, Max

    2004-01-01

    Electrochemical oxidation of polyethylene glycol (PEG) in an acidic (pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified (PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon (TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

  11. Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode

    Institute of Scientific and Technical Information of China (English)

    Rajesh S. Bejankiwar; Abir Basu; Max Cementi

    2004-01-01

    Electrochemical oxidation of polyethylene glycol(PEG) in an acidic(pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified(PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon(TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

  12. Anodic Bonding of Transparent Conductive Oxide Coated Silicon Wafer to Glass Substrate for Solar Cell Applications

    Science.gov (United States)

    Yuda, Yohei; Koida, Takashi; Kaneko, Tetsuya; Kondo, Michio

    2013-01-01

    We report on the anodic bonding of Si wafer coated by thin transparent conductive oxide (TCO) with a glass substrate, for the first time. We obtained sufficient bonding strength of as high as 9.5 MPa using a 30-nm-thick indium tin oxide (ITO) layer. We have also found that the ITO sample shows much stronger bonding strength does a sample that with a zinc oxide layer. The bonding mechanism is discussed in terms of the permeation of indium elements into the glass side driven by electric field. Finally we demonstrated a solar cell using this substrate.

  13. The anodization synthesis of copper oxide nanosheet arrays and their photoelectrochemical properties

    Science.gov (United States)

    Shu, Xia; Zheng, Hongmei; Xu, Guangqing; Zhao, Jiebo; Cui, Lihua; Cui, Jiewu; Qin, Yongqiang; Wang, Yan; Zhang, Yong; Wu, Yucheng

    2017-08-01

    We studied the growth of copper oxide nanosheet arrays on copper foil via a simple anodization method. The structures, morphologies, and elemental compositions of the specimens were characterized with an X-ray diffractometer, scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectrometer. The copper oxide (Cu2O and CuO) nanosheet arrays were comprised of 30-nm-thick nanosheets that stand vertically on the Cu substrate. The anodizing parameters, such as the current density, temperature, and polyethylene glycol concentration, were optimized to obtain the regular nanosheet arrays. The optical absorption properties of the anodized products were evaluated using a diffuse reflectance spectrometer, and broad and strong optical absorption bands arising from the UV to visible region were observed. The photoelectrochemical performance of the nanosheet arrays was measured with chronoamperometry and cyclic voltammetry on an electrochemical workstation equipped with a Xe lamp (wavelength >400 nm). A negative photocurrent was obtained due to the p-type semiconductor of the copper oxides. The copper oxide nanosheet arrays achieve the highest photocurrent of 0.4 mA/cm2 at the current density of 1.0 A/dm2, temperature of 70 °C, and polyethylene glycol concentration of 0.5 g/L.

  14. Effect of Oxide Inclusions on Electrochemical Properties of Aluminium Sacrificial Anodes

    Institute of Scientific and Technical Information of China (English)

    M. Emamy; A. Keyvani; M. Mahta; J. Campbell

    2009-01-01

    Oxide films are incorporated into melts by an entrainment process, and are expected to be present in most metals, but particularly cast Al alloys. The oxides are necessarily present as folded-over double films (bifilms) that are effectively cracks. Their effect on the electrochemical behaviour of cast Al-5Zn-0.02ln sacrificial anodes was studied in 3 wt pct sodium chloride solution using the NACE efficiency evaluation. Three methods were employed to entrain progressive amounts of oxide in the alloy, including the addition of Al-Zn-ln maching chips to the charge, increasing the pouring height, and agitating the melt. The introduction of oxide bifilms in the cast alloy resulted in the deterioration of the electrochemical properties of the sacrificial anodes, such as current capacity and anode efficiency, and introduced increasing variability in these properties. The results suggest that corrosion behaviour is strongly related to the presence of bifilms suspended in the liquid alloy because bifilms provide crack paths allowing the corrodant to penetrate deeply into the metal matrix, and simultaneously provide localized galvanic cells because of the precipitation of Fe rich intermetallic compounds on their outer surfaces.

  15. Treatment of methyl orange dye wastewater by cooperative electrochemical oxidation in anodic-cathodic compartment.

    Science.gov (United States)

    Pang, L; Wang, H; Bian, Z Y

    2013-01-01

    Electrochemical oxidation of methyl orange wastewater was studied using Ti/IrO(2)/RuO(2) anode and a self-made Pd/C O(2)-fed cathode in the divided cell with a terylene diaphragm. The result indicated that the appropriate rate of feeding air improved the methyl orange removal efficiency. The discoloration efficiency of methyl orange in the divided cell increased with increasing current density. The initial pH value had some effect on the discoloration of methyl orange, which became not obvious when the pH ranged from 2 to 10. However, the average removal efficiency of methyl orange wastewater in terms of total organic carbon (TOC) can reach 89.3%. The methyl orange structure had changed in the electrolytic process, and the characteristic absorption peak of methyl orange was about 470 nm. With the extension of electrolysis time, the concentration of methyl orange gradually reduced; wastewater discoloration rate increased gradually. The degradation of methyl orange was assumed to be cooperative oxidation by direct or indirect electrochemical oxidation at the anode and H(2)O(2), ·OH, O(2)(-)· produced by oxygen reduction at the cathode in the divided cell. Therefore, the cooperative electrochemical oxidation of methyl orange wastewater in the anodic-cathodic compartment had better degradation effects.

  16. Synthesis of Coral-Like Tantalum Oxide Films via Anodization in Mixed Organic-Inorganic Electrolytes

    Science.gov (United States)

    Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

    2013-01-01

    We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two–electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%. PMID:23799106

  17. The Effect of Anodic Oxide Films on the Nickel-Aluminum Reaction in Aluminum Braze Sheet

    Science.gov (United States)

    Tadgell, Colin A.; Wells, Mary A.; Corbin, Stephen F.; Colley, Leo; Cheadle, Brian; Winkler, Sooky

    2017-03-01

    The influence of an anodic oxide surface film on the nickel-aluminum reaction at the surface of aluminum brazing sheet has been investigated. Samples were anodized in a barrier-type solution and subsequently sputtered with nickel. Differential scanning calorimetry (DSC) and metallography were used as the main investigative techniques. The thickness of the anodic film was found to control the reaction between the aluminum substrate and nickel coating. Solid-state formation of nickel-aluminum intermetallic phases occurred readily when a relatively thin oxide film (13 to 25 nm) was present, whereas intermetallic formation was suppressed in the presence of thicker oxides ( 60 nm). At an intermediate oxide film thickness of 35 nm, the Al3Ni phase formed shortly after the initiation of melting in the aluminum substrate. Analysis of DSC traces showed that formation of nickel-aluminum intermetallic phases changed the melting characteristics of the aluminum substrate, and that the extent of this change can be used as an indirect measure of the amount of nickel incorporated into the intermetallic phases.

  18. Synthesis of coral-like tantalum oxide films via anodization in mixed organic-inorganic electrolytes.

    Directory of Open Access Journals (Sweden)

    Hongbin Yu

    Full Text Available We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two-electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%.

  19. Biological insertion of nanostructured germanium and titanium oxides into diatom biosilica

    Science.gov (United States)

    Jeffryes, Clayton S.

    There is significant interest in titanium oxide and germanium-silicon oxide nanocomposites for optoelectronic, photocatalytic, and solar cell applications. The ability of the marine diatom Pinnularia sp. to uptake soluble metal oxides from cell culture medium, and incorporate them into the micro- and nano-structure of their amorphous silica cell walls, called frustules, was evaluated using an engineered photobioreactor system. The effects of metal oxides on the structural and elemental properties of the frustule were also evaluated. Diatom cell cultures grown in 5 L photobioreactors were initially charged with 0.5 mM of soluble silicon, Si(OH)4, an obligate substrate required for frustule fomation. Upon exhaustion of Si(OH)4 cells were exposed to the mixed pulse-addition of soluble silicon and germanium or co-perfusion addition of soluble silicon and titanium, which were incorporated into the frustules. Metals composition of the cell culture medium, diatom biomass and purified frustules were measured, as was the local elemental composition within the frustule pores and the metal oxide crystallinity. Diatom frustules having a germanium composition of 1.6 wt % were devoid of the native intra-pore structures and possessed enhanced photoluminescence and electroluminescence when compared to frustules without Ge. Diatoms cultivated in the presence of soluble titanium incorporated amorphous titania into the frustule, which maintained native structure even when local TiO2 concentrations within the nanopores approached 60 wt. %. Titanium oxide could also be biomimetically deposited directly within the diatom nanopores by adsorbing poly-L-lysine to the diatom biosilica where it catalyzed the soluble titanium precursor Ti-BALDH into amorphous titania nanoparticles. Both biogenic and biomimetic titania could be converted to anatase titanium by thermal annealing. It was determined that nanostructured metal oxide composites can be fabricated biomimetically or in cell culture to

  20. High-resolution elemental mapping of titanium oxide/aluminium oxide multilayer by spectrum-imaging.

    Science.gov (United States)

    Kurata, H; Kumagai, H; Ozasa, K

    2001-01-01

    A spectrum-imaging technique based on scanning transmission electron microscopy combined with an electron energy-loss spectroscopy has been applied for the multilayer of amorphous titanium oxide and aluminium oxide layers on silicon substrate. We demonstrate the high-resolution elemental mapping and discuss the advantage of this method compared to an energy-filtering transmission electron microscopy. The main advantage is the absence of chromatic broadening, which allows the use of a large collection angle to acquire spectrum-image data and a wide energy window to integrate the core-loss signals. This suggests that the spatial resolution of elemental maps is mainly determined by the size of the electron probe.

  1. A facile synthesis of zinc oxide/multiwalled carbon nanotube nanocomposite lithium ion battery anodes by sol-gel method

    Science.gov (United States)

    Köse, Hilal; Karaal, Şeyma; Aydın, Ali Osman; Akbulut, Hatem

    2015-11-01

    Free standing zinc oxide (ZnO) and multiwalled carbon nanotube (MWCNT) nanocomposite materials are prepared by a sol gel technique giving a new high capacity anode material for lithium ion batteries. Free-standing ZnO/MWCNT nanocomposite anodes with two different chelating agent additives, triethanolamine (TEA) and glycerin (GLY), yield different electrochemical performances. Field emission gun scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrometer (EDS), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analyses reveal the produced anode electrodes exhibit a unique structure of ZnO coating on the MWCNT surfaces. Li-ion cell assembly using a ZnO/MWCNT/GLY free-standing anode and Li metal cathode possesses the best discharge capacity, remaining as high as 460 mAh g-1 after 100 cycles. This core-shell structured anode can offer increased energy storage and performance over conventional anodes in Li-ion batteries.

  2. Dependence of Performance of Organic Light-emitting Devices on Sheet Resistance of Indium-tin-oxide Anodes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The dependence of the performance of organic light-emitting devices(OLEDs) on the sheet resistance of indium-tin-oxide(ITO) anodes was investigated by measuring the steady state current density brightness voltage characteristics and the electroluminescent spectra. The device with a higher sheet resistance anode shows a lower current density, a lower brightness level, and a higher operation voltage. The electroluminescence(EL) efficiencies of the devices with the same structure but different ITO anodes show more complicated differences. Furthermore, the shift of the light-emitting zone toward the anode was found when an anode with a higher sheet resistance was used. These performance differences are discussed and attributed to the reduction of hole injection and the increase in voltage drop over ITO anode with the increase in sheet resistance.

  3. Formation of Ultrafine Metal Particles and Metal Oxide Precursor on Anodized Al by Electrolysis Deposition

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Nickel was deposited by ac electrolysis deposition in the pores of the porous oxide film of Al produced by anodizing in phosphoric acid. Ultrafine rod-shaped Ni particles were formed in the pores. At the same time a film of Ni oxide precursor was developed on the surface of the porous oxide film. The Ni particles and the Ni oxide precursor were examined by SEM, TEM and X-ray diffraction. The thickness of the barrier layer of the porous oxide film was thin and it attributed to the formation of the metal particles, while the formation of the oxide precursor was associated with the surface pits which were developed in the pretreatment of Al.

  4. Production of hydroxyapatite layers on the plasma electrolytically oxidized surface of titanium alloys.

    Science.gov (United States)

    Lugovskoy, Alex; Lugovskoy, Svetlana

    2014-10-01

    Hydroxyapatite (HA) is a bioactive material that is widely used for improving the osseointegration of titanium dental implants. Titanium can be coated with HA by various methods, such as chemical vapor deposition (CVD), thermal spray, or plasma spray. HA coatings can also be grown on titanium surfaces by hydrothermal, chemical, and electrochemical methods. Plasma electrolytic oxidation (PEO), or microarc oxidation (MAO), is an electrochemical method that enables the production of a thick porous oxide layer on the surface of a titanium implant. If the electrolyte in which PEO is performed contains calcium and phosphate ions, the oxide layer produced may contain hydroxyapatite. The HA content can then be increased by subsequent hydrothermal treatment. The HA thus produced on titanium surfaces has attractive properties, such as a high porosity, a controllable thickness, and a considerable density, which favor its use in dental and bone surgery. This review summarizes the state of the art and possible further development of PEO for the production of HA on Ti implants.

  5. Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide

    Science.gov (United States)

    Riazanova, A. V.; Costanzi, B. N.; Aristov, A. I.; Rikers, Y. G. M.; Mulders, J. J. L.; Kabashin, A. V.; Dahlberg, E. Dan; Belova, L. M.

    2016-03-01

    Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10-6 in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm-1. The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

  6. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    Directory of Open Access Journals (Sweden)

    Naofumi Uekawa

    2012-01-01

    Full Text Available Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO2 nanoparticles.

  7. Influence of substrate microstructure on the growth of anodic oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Fratila-Apachitei, L.E.; Terryn, H.; Skeldon, P.; Thompson, G.E.; Duszczyk, J.; Katgerman, L

    2004-03-15

    The effects of permanent mold cast microstructure on the growth of anodic oxide layers on three different aluminum substrates (i.e. Al99.8, AlSi10, and AlSi10Cu3, wt.%) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), and laser scanning confocal microscopy (LSCM). The anodic oxidation was performed galvanostatically in 2.25 M H{sub 2}SO{sub 4}, at 0 deg. C. The oxide layers developed a microscale topography mainly determined by the morphology of aluminum grains and cells. A low amount of insoluble impurities, uniformly distributed, would contribute to the growth of oxide layers with minimum defects and uniform thickness on the pure aluminum substrate whereas for the binary and ternary systems, a fine cell structure and a modified morphology of Si particles would be favorable. The Al-Fe and Al-Fe-Si particles were occluded in the oxide layers next to Si particles, blocking locally the oxide growth whereas Al{sub 2}Cu particles were preferentially oxidized. In addition, the presence of Si particles in the layer influenced pore morphology by development of deflected pores around the particles.

  8. Fabrication of polymeric nano-batteries array using anodic aluminum oxide templates.

    Science.gov (United States)

    Zhao, Qiang; Cui, Xiaoli; Chen, Ling; Liu, Ling; Sun, Zhenkun; Jiang, Zhiyu

    2009-02-01

    Rechargeable nano-batteries were fabricated in the array pores of anodic aluminum oxide (AAO) template, combining template method and electrochemical method. The battery consisted of electropolymerized PPy electrode, porous TiO2 separator, and chemically polymerized PAn electrode was fabricated in the array pores of two-step anodizing aluminum oxide (AAO) membrane, based on three-step assembling method. It performs typical electrochemical battery behavior with good charge-discharge ability, and presents a capacity of 25 nAs. AFM results show the hexagonal array of nano-batteries' top side. The nano-battery may be a promising device for the development of Micro-Electro-Mechanical Systems (MEMS), and Nano-Electro-Mechanical Systems (NEMS).

  9. Growth Kinetics of Anodic Oxide Films Formed on Zircaloy-2 in Various Electrolytes

    Directory of Open Access Journals (Sweden)

    V. Jeevana Jyothi

    2009-01-01

    Full Text Available The Kinetics of anodic oxidation of zircaloy-2 have been studied at current densities ranging from 4 to 12 mA cm-2 at room temperature in order to investigate the dependence of ionic current density on the field across the oxide film. Thickness of the anodic films was estimated from capacitance data. The formation rate, current efficiency and differential field were found to increase with increase in the ionic current density for zircaloy-2. Plots of logarithm of formation rate vs. logarithm of current density is fairly linear. From linear plots of logarithm of ionic current density vs. differential field and applying the Cabrera - Mott theory, the half - jump distance (a and height of energy barrier (W were deduced.

  10. Transformation and removal of arsenic in groundwater by sequential anodic oxidation and electrocoagulation

    Science.gov (United States)

    Zhang, Peng; Tong, Man; Yuan, Songhu; Liao, Peng

    2014-08-01

    Oxidation of As(III) to As(V) is generally essential for the efficient remediation of As(III)-contaminated groundwater. The performance and mechanisms of As(III) oxidation by an as-synthesized active anode, SnO2 loaded onto Ti-based TiO2 nanotubes (Ti/TiO2NTs/Sb-SnO2), were investigated. The subsequent removal of total arsenic by electrocoagulation (EC) was further tested. The Ti/TiO2NTs/Sb-SnO2 anode showed a high and lasting electrochemical activity for As(III) oxidation. 6.67 μM As(III) in synthetic groundwater was completely oxidized to As(V) within 60 min at 50 mA. Direct electron transfer was mainly responsible at the current below 30 mA, while hydroxyl radicals contributed increasingly with the increase in the current above 30 mA. As(III) oxidation was moderately inhibited by the presence of bicarbonate (20 mM), while was dramatically increased with increasing the concentration of chloride (0-10 mM). After the complete oxidation of As(III) to As(V), total arsenic was efficiently removed by EC in the same reactor by reversing electrode polarity. The removal efficiency increased with increasing the current but decreased by the presence of phosphate and silica. Anodic oxidation represents an effective pretreatment approach to increasing EC removal of As(III) in groundwater under O2-limited conditions.

  11. Electrocatalytic Oxidation of Cellulose to Gluconate on Carbon Aerogel Supported Gold Nanoparticles Anode in Alkaline Medium

    OpenAIRE

    Hanshuang Xiao; Meifen Wu; Guohua Zhao

    2015-01-01

    The development of high efficient and low energy consumption approaches for the transformation of cellulose is of high significance for a sustainable production of high value-added feedstocks. Herein, electrocatalytic oxidation technique was employed for the selective conversion of cellulose to gluconate in alkaline medium by using concentrated HNO3 pretreated carbon aerogel (CA) supported Au nanoparticles as anode. Results show that a high gluconate yield of 67.8% and sum salts yield of 88.9...

  12. Anodic aluminium oxide membranes used for the growth of carbon nanotubes.

    Science.gov (United States)

    López, Vicente; Morant, Carmen; Márquez, Francisco; Zamora, Félix; Elizalde, Eduardo

    2009-11-01

    The suitability of anodic aluminum oxide (AAO) membranes as template supported on Si substrates for obtaining organized iron catalyst for carbon nanotube (CNT) growth has been investigated. The iron catalyst was confined in the holes of the AAO membrane. CVD synthesis with ethylene as carbon source led to a variety of carbon structures (nanotubes, helices, bamboo-like, etc). In absence of AAO membrane the catalyst was homogeneously distributed on the Si surface producing a high density of micron-length CNTs.

  13. Aluminum oxide as a dual-functional modifier of Ni-based anodes of solid oxide fuel cells for operation on simulated biogas

    Science.gov (United States)

    Wang, Feng; Wang, Wei; Ran, Ran; Tade, Moses O.; Shao, Zongping

    2014-12-01

    Al2O3 and SnO2 additives are introduced into the Ni-YSZ cermet anode of solid oxide fuel cells (SOFCs) for operation on simulated biogas. The effects of incorporating Al2O3/SnO2 on the electrical conductivity, morphology, coking resistance and catalytic activity for biogas reforming of the cermet anode are systematically studied. The electrochemical performance of the internal reforming SOFC is enhanced by introducing an appropriate amount of Al2O3 into the anode, but it becomes worse with excess alumina addition. For SnO2, a negative effect on the electrochemical performance is demonstrated, although the coking resistance of the anode is improved. For fuel cells operating on biogas, stable operation under a polarization current for 130 h at 750 °C is achieved for a cell with an Al2O3-modified anode, while cells with unmodified or SnO2-modified Ni-YSZ anodes show much poorer stability under the same conditions. The improved performance of the cell with the Al2O3-modified anode mainly results from the suppressed coking and sintering of the anode and from the formation of NiAl2O4 in the unreduced anode. In sum, modifying the anode with Al2O3 may be a useful and facile way to improve the coking resistance and electrochemical performance of the nickel-based cermet anodes for SOFCs.

  14. Thulium and ytterbium-doped titanium oxide thin films deposited by ultrasonic spray pyrolysis

    OpenAIRE

    Forissier, S.; Roussel, H.; Chaudouet, P.; Pereira, A.; Deschanvres, J.-L.; B. Moine

    2012-01-01

    Thin films of thulium and ytterbium-doped titanium oxide were grown by metal-organic spray pyrolysis deposition from titanium(IV)oxide bis(acetylacetonate), thulium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and ytterbium(III) tris(acetylacetonate). Deposition temperatures have been investigated from 300{\\deg}C to 600{\\deg}C. Films have been studied regarding their crystallity and doping quality. Structural and composition characterisations of TiO2:Tm,Yb were performed by electron micr...

  15. Characterization of bioactive ceramic coatings prepared on titanium implants by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Micro-arc oxidation (MAO) is an enhanced chemical technology in an electrolyte medium to obtain coating structures on valve-metal surfaces. Titanium oxide films obtained by MAO in the sodium phosphate electrolyte were investigated. The films were composed mainly of TiO2 phases in the form of anatase and rutile and enriched with Na and P elements at the surface. Their apatite-inducing ability was evaluated in a simulated body fluid (SBF). When immersing in SBF for over 30 d, a preferential carbonated-hydroxyapatite was formed on the surfaces of the films, which suggests that the MAO-treated titanium has a promising positive biological response.

  16. Characterization of calcium phosphate deposited on valve metal by anodic oxidation with polarity inversion.

    Science.gov (United States)

    Okawa, Seigo; Homma, Kikuo; Kanatani, Mitsugu; Watanabe, Kouichi

    2009-07-01

    Electrochemical deposition of calcium phosphate (CAP) on valve metals such as Ta, Nb, and Zr, was performed by anodic oxidation with alternate polarity inversion at an applied 20 VDC. A saturated hydroxyapatite(HAP)-phosphoric acid solution (pH 3) was used as the electrolyte. FTIR, XRD, and XPS were employed to investigate the detailed characteristics of the deposition. HAP was precipitated on Ta; HAP including brushite and monetite on Nb; and HAP and monetite on Zr. The Ca/P atomic ratios were 1.3-1.5 by XPS, and HPO(4)(2- )bands were detected on Ta by FTIR. Therefore, the HAP precipitated on Ta was a Ca-deficient HAP. In addition, the XPS spectra of the specimens showed that phosphate ions were incorporated into the anodic oxide film. Deposits with nano-grain size were observed by AFM. The results confirmed that CAP with nano-grain size was deposited on valve metals by the anodic oxidation with polarity inversion.

  17. Retarding of electrochemical oxidation of formate on the platinum anode by a coat of Nafion membrane

    Science.gov (United States)

    Zhang, Rui; Lv, Weixin; Li, Guanghua; Mezaal, Mohammed Adnan; Li, Xiaojing; Lei, Lixu

    2014-12-01

    It has been found that the faradaic efficiency is decreasing with the electrolysis time for electrochemical reduction of CO2 to formate on a Sn cathode with a Pt anode in an undivided electrolytic cell, because the oxidation of formed formate takes place on the Pt anode, which also limits seriously the highest concentration of formate in the system. Here, we report that a coat of Nafion membrane on the Pt anode can retard the oxidation of formate: even if the concentration of the formate in the electrolyte reaches to 0.12 mol L-1, the faradaic efficiency still maintains above 61.3%; in contrast, the oxidation reaction of the formate on the naked Pt electrode is very fast, when the concentration of the formate in the electrolyte reaches to 0.023 mol L-1, the faradaic efficiency decreases to 35.3%. This is very important because the separation of formic acid could not be economical when its concentration is not high enough, and it is also costly if the depleted solution allows too less of its concentration because the solution has to be reused in the electrochemical process.

  18. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Pei Hsuan Doris Lu

    2015-01-01

    Full Text Available This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodising in electrolytes containing the extrinsic impurities in ionic form. The ions become trapped in the formed anodic oxide during anodisation, therefore enabling the impurity to be introduced into the silicon, with aluminium, during laser-doping. This codoping process can be used to create very heavily doped surface layers which can reduce contact resistance on metallisation, whilst the deeper doping achieved by the intrinsic aluminium may act to shield the surface from minority carriers. laser-doping through AAO layers can be performed without introducing any voids in the silicon or fumes which may be harmful to human health.

  19. A dual-cathode electro-Fenton oxidation coupled with anodic oxidation system used for 4-nitrophenol degradation.

    Science.gov (United States)

    Chu, Y Y; Qian, Y; Wang, W J; Deng, X L

    2012-01-15

    The degradation of 4-nitrophenol was investigated using a novel electrochemical oxidation system, in which the anodic oxidation at Ti/SnO(2)-Sb(2)O(5)-IrO(2) electrode and the electro-Fenton oxidation with two cathodes were involved. In this system, gas diffusion electrode (GDE) was used to generate H(2)O(2) by O(2) reduction and graphite electrode was employed for the reduction of Fe(3+) regenerating Fe(2+). When the potential values of GDE and graphite cathode were controlled at -0.80 and -0.10 V/SCE respectively, the optimum Fe(2+) concentration for 4-nitrophenol degradation was about 0.10mM, much lower than the concentration of 0.25 mM obtained in the single-cathode system. Due to the combination of electro-Fenton oxidation and anodic oxidation, an effective degradation and a high mineralization current efficiency (MCE) were achieved. After 600 min treatment, 74.5% of the original TOC was removed by the dual-cathode oxidation system. Moreover, it was confirmed that 57.0% of the original nitrogen could be removed in gaseous form from the simulated wastewater. These results indicate that this electrochemical oxidation process might provide an alternative for the degradation of organic pollutants. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Multifunctional porous titanium oxide coating with apatite forming ability and photocatalytic activity on a titanium substrate formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Akatsu, T; Yamada, Y; Hoshikawa, Y; Onoki, T; Shinoda, Y; Wakai, F

    2013-12-01

    Plasma electrolytic oxidation (PEO) was used to make a multifunctional porous titanium oxide (TiO2) coating on a titanium substrate. The key finding of this study is that a highly crystalline TiO2 coating can be made by performing the PEO in an ammonium acetate (CH3COONH4) solution; the PEO coating was formed by alternating between rapid heating by spark discharges and quenching in the solution. The high crystallinity of the TiO2 led to the surface having multiple functions, including apatite forming ability and photocatalytic activity. Hydroxyapatite formed on the PEO coating when it was soaked in simulated body fluid. The good apatite forming ability can be attributed to the high density of hydroxyl groups on the anatase and rutile phases in the coating. The degradation of methylene blue under ultraviolet radiation indicated that the coating had high photocatalytic activity.

  1. Growth control of carbon nanotubes using by anodic aluminum oxide nano templates.

    Science.gov (United States)

    Park, Yong Seob; Choi, Won Seek; Yi, Junsin; Lee, Jaehyeong

    2014-05-01

    Anodic Aluminum Oxide (AAO) template prepared in acid electrolyte possess regular and highly anisotropic porous structure with pore diameter range from five to several hundred nanometers, and with a density of pores ranging from 10(9) to 10(11) cm(-2). AAO can be used as microfilters and templates for the growth of CNTs and metal or semiconductor nanowires. Varying anodizing conditions such as temperature, electrolyte, applied voltage, anodizing and widening time, one can control the diameter, the length, and the density of pores. In this work, we deposited Al thin film by radio frequency magnetron sputtering method to fabricate AAO nano template and synthesized multi-well carbon nanotubes on a glass substrate by microwave plasma-enhanced chemical vapor deposition (MPECVD). AAO nano-porous templates with various pore sizes and depths were introduced to control the dimension and density of CNT arrays. The AAO nano template was synthesize on glass by two-step anodization technique. The average diameter and interpore distance of AAO nano template are about 65 nm and 82 nm. The pore density and AAO nano template thickness are about 2.1 x 10(10) pores/cm2 and 1 microm, respectively. Aligned CNTs on the AAO nano template were synthesized by MPECVD at 650 degrees C with the Ni catalyst layer. The length and diameter of CNTs were grown 2 microm and 50 nm, respectively.

  2. Oxidation of H2 and CO in a fuel cell with a Platinum-tin Anode

    Directory of Open Access Journals (Sweden)

    Javier González

    2010-06-01

    Full Text Available This report describes the construction and evolution of a fuel cell with a bi-metallic anode of Pt-Sn supported on carbon, as catalysts for oxidation of pure hydrogen, pure CO and a 2% CO in H2 mixture. Both, cathode and anode were made with a structure composed by a diffusive layer and a catalytic layer. The diffusive layer was made with a carbon cloth while the catalytic layer contained the platinum and tin supported on carbon. To test the performance of the catalytic mixture, a proton exchange membrane fuel cell (PEMFC was developed with an original design for the gas distributation plates. The reactants were feed to ambient temperature and 3 psig in the anode side, while 5 psig pure oxygen was used in the cathode. The anode catalytic load was 0.57 mg/cm2 of platinum and 0.08 mg/cm2 of tin. The catalytic load in cathode was 0.85 mg/cm2 of pure platinum. It was found that this caralytic mixture is tolerant to CO presence.

  3. Photocatalytic oxidation mechanism of alkanes in contact with titanium dioxide

    Science.gov (United States)

    Formenti, M.; Juillet, F.; Teichner, S. J.

    1977-01-01

    Isobutane was photooxidized on titanium dioxide between -16 and +180 C in tertiary butanol and acetone. The formation of tertiary butanol preceded the formation of acetone. Above 20 C the latter compound became clearly predominant. The reaction kinetics obeyed a steady state model of oxygen chemisorption with the involvement of isobutane in the physisorbed phase.

  4. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    Science.gov (United States)

    Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

  5. Photocatalytic Oxidation of a Volatile Organic Component of Acetaldehyde Using Titanium Oxide Nanotubes

    Directory of Open Access Journals (Sweden)

    Yifeng Wang

    2007-01-01

    Full Text Available Titanium oxide nanotubes are prepared and treated with Au (Au/nanotube sample and Pt (Pt/nanotube sample, and the photoactivity of these catalysts compared to a standard Degussa P25 photocatalyst is investigated. The samples were analyzed using X-ray diffraction, field emission gun scanning transmission electron microscopy (STEM. Both high-resolution TEM images and high-angle annular dark-field (HAAD images were recorded for the specimens. Oxidation of acetaldehyde was used to test the efficiency of the catalysts. Nanotube samples showed better photoactivity than the standard P25, because the P25 titania deactivates quickly. Enhanced reactivity of the nanotube is related to surface charge polarity developed on outer and inner surfaces due to the difference in overlap of oxygen anions that resulted from curving of octahedral sheets. A tentative and qualitative surface polarity model is proposed for enhancing electron-hole pair separation. The inner surface benefits reduction; whereas, the outer surface benefits oxidation reactions. Both the metal identity and the size of the metal particles in the nanotubes affected the photocatalytic activity. Specifically, the addition of platinum increased the activity significantly, and increased the total yield. The addition of gold had lesser impact compared to the platinum. Formation of Pt large nanoparticles on the nanotube surfaces reduces the oxidation reactivity.

  6. Optimization of Oxidation Temperature for Commercially Pure Titanium to Achieve Improved Corrosion Resistance

    Science.gov (United States)

    Bansal, Rajesh; Singh, J. K.; Singh, Vakil; Singh, D. D. N.; Das, Parimal

    2017-02-01

    Thermal oxidation of commercially pure titanium (cp-Ti) was carried out at different temperatures, ranging from 200 to 900 °C to achieve optimum corrosion resistance of the thermally treated surface in simulated body fluid. Scanning electron microscopy, x-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy techniques were used to characterize the oxides and assess their protective properties exposed in the test electrolyte. Maximum resistance toward corrosion was observed for samples oxidized at 500 °C. This was attributed to the formation of a composite layer of oxides at this temperature comprising Ti2O3 (titanium sesquioxide), anatase and rutile phases of TiO2 on the surface of cp-Ti. Formation of an intact and pore-free oxide-substrate interface also improved its corrosion resistance.

  7. Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Panizza, M. [Department of Chemical and Process Engineering, University of Genoa, P.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Kapalka, Agnieszka [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Comninellis, Ch. [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)], E-mail: christos.comninellis@epfl.ch

    2008-01-01

    In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency.

  8. Large Aperture Low Threshold Current 980nm VCSELs Fabricated with Pulsed Anodic Oxidation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Pulsed anodic oxidation technique, a new way of forming current blocking layers, was successfully used in ridge-waveguide QW laser fabrication. This method was applied in 980 nm VCSELs fabrication to form a high-quality native oxide current blocking layer, which simplifies the device process. A significant reduction of threshold current and a distinguished device performance are achieved. The 500 μm diameter device has a current threshold as low as 0.48 W. The maximum CW operation output power at room tempe...

  9. Electrocatalytic Materials and Techniques for the Anodic Oxidation of Various Organic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Treimer, Stephen Everett [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The focus of this thesis was first to characterize and improve the applicability of Fe(III) and Bi(V) doped PbO2 film electrodes for use in anodic O-transfer reactions of toxic and waste organic compounds, e.g. phenol, aniline, benzene, and naphthalene. Further, they investigated the use of alternative solution/electrode interfacial excitation techniques to enhance the performance of these electrodes for remediation and electrosynthetic applications. Finally, they have attempted to identify a less toxic metal oxide film that may hold promise for future studies in the electrocatalysis and photoelectrocatalysis of O-transfer reactions using metal oxide film electrodes.

  10. Nano-hardness and elastic modulus of anodic aluminium oxide based Poly (2-hydroxyethylmethacrylate composite membranes

    Directory of Open Access Journals (Sweden)

    Gérrard Eddy Jai Poinern

    2014-07-01

    Full Text Available In this study we determine the elastic and hardness properties of electrochemically engineered porous anodic aluminium oxide (AAO membranes and AAO membranes infiltrated with Poly (2-hydroxyethylmethacrylate to form a unique biologically compatible AAO/polymer composite. The electrochemically-synthesised membranes have a nanometre scale porous oxide structure with a mean pore diameter of 100 nm. The membranes were characterized using field emission scanning electron microscopy before and after polymer infiltration. The polymer treated and untreated membranes were then examined using the nano-indentation technique to measure the hardness and subsequently determine the membrane elasticity.

  11. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Chang BYS

    2012-07-01

    Full Text Available Betty Yea Sze Chang,1 Nay Ming Huang,1 Mohd Nor An' amt,2 Abdul Rahman Marlinda,1 Yusoff Norazriena,1 Muhamad Rasat Muhamad,3 Ian Harrison,4 Hong Ngee Lim,5 Chin Hua Chia61Low Dimensional Materials Research Center, Physics Department, University of Malaya, Kuala Lumpur; 2Faculty of Agro Industry and Natural Resources (FASA, Universiti Malaysia Kelantan, Kota Bharu, Kelantan; 3The Chancellery Building, Multimedia University, Persiaran Multimedia, Cyberjaya, Selangor; 4School of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Semenyih, Selangor; 5Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 6School of Applied Physics, Universiti Kebangsaan Malaysia, Bangi, Selangor, MalaysiaAbstract: A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm. Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II ions in potassium chloride electrolyte.Keywords: graphene oxide, titanium oxide, hydrothermal, nanocomposite

  12. Development of Ni-Ba(Zr,Y)O3 cermet anodes for direct ammonia-fueled solid oxide fuel cells

    Science.gov (United States)

    Miyazaki, Kazunari; Okanishi, Takeou; Muroyama, Hiroki; Matsui, Toshiaki; Eguchi, Koichi

    2017-10-01

    In this study, the availability of Ni-Ba(Zr,Y)O3-δ (BZY) cermet for the anode of direct ammonia-fueled solid oxide fuel cells (SOFCs) is evaluated. In this device, the anodes need to be active for the catalytic ammonia decomposition as well as the electrochemical hydrogen oxidation. In the catalytic activity test, ammonia decomposes completely over Ni-BZY at ca. 600 °C, while higher temperature is required to accomplish the complete decomposition over the conventional SOFC anode of Ni-yttria-stabilized zirconia cermet. The high activity of Ni-BZY is attributed to the high basicity of BZY and the high resistance to hydrogen poisoning effect. The electrochemical property of Ni-BZY anode is also evaluated with the anode-supported cell of Ni-BZY|BZY|Pt at 600-700 °C with feeding ammonia or hydrogen as a fuel. Since the residence time of ammonia fuel in the thick Ni-BZY anode is long, the difference in the cell performance between two fuels is relatively small. Furthermore, it is proved that the steam concentration in the fuel strongly affects the cell performance. We find that this factor is important to satisfy the above mentioned requirements for the anode of direct ammonia-fueled SOFCs. Throughout this study, it is concluded that Ni-BZY cermet will be a promising anode.

  13. Graphite coated with manganese oxide/multiwall carbon nanotubes composites as anodes in marine benthic microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yubin, E-mail: ffyybb@ouc.edu.cn; Yu, Jian; Zhang, Yelong; Meng, Yao

    2014-10-30

    Highlights: • MnO{sub 2}/MWCNTs composites anode exhibits faster reaction kinetics. • The surfaces of MnO{sub 2}/MWCNTs composites anode exhibits better wettability. • A BMFC using the modified anode have excellent power output. - Abstract: Improving anode performance is of great significance to scale up benthic microbial fuel cells (BMFCs) for its marine application to drive oceanography instruments. In this study, manganese oxide (MnO{sub 2})/multiwall carbon nanotubes (MWCNTs) composites are prepared to be as novel anodes in the BMFCs via a direct redox reaction between permanganate ions (MnO{sub 4}{sup −}) and MWCNTs. The results indicate that the MnO{sub 2}/MWCNTs anode has a better wettability, greater kinetic activity and higher power density than that of the plain graphite (PG) anode. It is noted that the MnO{sub 2} (50% weight percent)/MWCNTs anode shows the highest electrochemical performance among them and will be a promising material for improving bioelectricity production of the BMFCs. Finally, a synergistic mechanism of electron transfer shuttle of Mn ions and their redox reactions in the interface between modified anode and bacteria biofilm are proposed to explain its excellent electrochemical performance.

  14. Oxochloroalkoxide of the Cerium (IV and Titanium (IV as oxides precursor

    Directory of Open Access Journals (Sweden)

    Machado Luiz Carlos

    2002-01-01

    Full Text Available The Cerium (IV and Titanium (IV oxides mixture (CeO2-3TiO2 was prepared by thermal treatment of the oxochloroisopropoxide of Cerium (IV and Titanium (IV. The chemical route utilizing the Cerium (III chloride alcoholic complex and Titanium (IV isopropoxide is presented. The compound Ce5Ti15Cl16O30 (iOPr4(OH-Et15 was characterized by elemental analysis, FTIR and TG/DTG. The X-ray diffraction patterns of the oxides resulting from the thermal decomposition of the precursor at 1000 degreesC for 36 h indicated the formation of cubic cerianite (a = 5.417Å and tetragonal rutile (a = 4.592Å and (c = 2.962 Å, with apparent crystallite sizes around 38 and 55nm, respectively.

  15. Nanosegregated bimetallic oxide anode catalyst for proton exchange membrane electrolyzer

    Science.gov (United States)

    Danilovic, Nemanja; Kang, Yijin; Markovic, Nenad; Stamenkovic, Vojislav; Myers, Deborah J.; Subbaraman, Ram

    2016-08-23

    A surface segregated bimetallic composition of the formula Ru.sub.1-xIr.sub.x wherein 0.1.ltoreq.x.ltoreq.0.75, wherein a surface of the material has an Ir concentration that is greater than an Ir concentration of the material as a whole is provided. The surface segregated material may be produced by a method including heating a bimetallic composition of the formula Ru.sub.1-xIr.sub.x, wherein 0.1.ltoreq.x.ltoreq.0.75, at a first temperature in a reducing environment, and heating the composition at a second temperature in an oxidizing environment. The surface segregated material may be utilized in electrochemical devices.

  16. Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission.

    Science.gov (United States)

    Pomfret, Michael B; Steinhurst, Daniel A; Owrutsky, Jeffrey C

    2013-04-18

    Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH4 as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO2(g) and CO(g), are observed while cells are under load. A broad feature at 2295 cm(-1) is assigned to CO2 adsorbed on Ni as a CH4 oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH4 operation. Electrochemical control provides confirmation of the assignment of adsorbed CO2. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry.

  17. Electrochemical Oxidation of Ammonia on Ir Anode in Potential Fixed Electrochemical Sensor

    Institute of Scientific and Technical Information of China (English)

    HAN Yi-ping; LUO Peng; CAI Chen-xin; XIE Lei; LU Tian-hong

    2008-01-01

    Ir catalyst possesses a good electrocatalytic activity and selectivity for the oxidation of NH3 and/or NH4OH at Ir anode in the potential fixed electrochemical sensor with the neutral solution.Owing to the same electrochemical behavior of NH3 and NH4OH in a NaCIO4 solution,NH4OH can be used instead of NH3 for the experimental convenience.It was found that the potential of the oxidation peak of NH4OH at the Ir/GC electrode in NaCIO4 solutions is at about 0.85 V,and the current density of the oxidation peak of NH4OH is linearly proportional to the concentration of NH4OH.The electrocatalytic oxidation of NH4OH is diffusion-controlled.Especially,Ir has no electrocatalytic activity for the CO oxidation,illustrating that CO does not interfere in the measurement of NH4OH and the potential fixed electrochemical NH3 sensor with the neutral solution,and the anodic Ir catalyst possesses a good selectivity.Therefore,lr may have practical application in the potential fixed electrochemical NH3 sensor with the neutral solution.

  18. Titanium Oxide/Platinum Catalysis: Charge Transfer from a Titanium Oxide Support Controls Activity and Selectivity in Methanol Oxidation on Platinum

    KAUST Repository

    Hervier, Antoine

    2011-11-24

    Platinum films of 1 nm thickness were deposited by electron beam evaporation onto 100 nm thick titanium oxide films (TiOx) with variable oxygen vacancy concentrations and fluorine (F) doping. Methanol oxidation on the platinum films produced formaldehyde, methyl formate, and carbon dioxide. F-doped samples demonstrated significantly higher activity for methanol oxidation when the TiOx was stoichiometric (TiO 2), but lower activity when it was nonstoichiometric (TiO 1.7 and TiO1.9). These results correlate with the chemical behavior of the same types of catalysts in CO oxidation. Fluorine doping of stoichiometric TiO2 also increased selectivity toward partial oxidation of methanol to formaldehyde and methyl formate, but had an opposite effect in the case of nonstoichiometric TiOx. Introduction of oxygen vacancies and fluorine doping both increased the conductivity of the TiO x film. For oxygen vacancies, this occurred by the formation of a conduction channel in the band gap, whereas in the case of fluorine doping, F acted as an n-type donor, forming a conduction channel at the bottom of the conduction band, about 0.5-1.0 eV higher in energy. The higher energy electrons in F-doped stoichiometric TiOx led to higher turnover rates and increased selectivity toward partial oxidation of methanol. This correlation between electronic structure and turnover rate and selectivity indicates that the ability of the support to transfer charges to surface species controls in part the activity and selectivity of the reaction. © 2011 American Chemical Society.

  19. Anodic oxidation of o-nitrophenol on BDD electrode: variable effects and mechanisms of degradation.

    Science.gov (United States)

    Rabaaoui, Nejmeddine; Saad, Mohamed El Khames; Moussaoui, Younes; Allagui, Mohamed Salah; Bedoui, Ahmed; Elaloui, Elimame

    2013-04-15

    The electrochemical oxidation of pesticide, o-nitrophenol (ONP) as one kind of pesticide that is potentially dangerous and biorefractory, was studied by galvanostatic electrolysis using boron-doped diamond (BDD) as anode. The influence of several operating parameters, such as applied current density, supporting electrolyte, and initial pH value, was investigated. The best degradation occurred in the presence of Na2SO4 (0.05 M) as conductive electrolyte. After 8h, nearly complete degradation of o-nitrophenol was achieved (92%) using BDD electrodes at pH 3 and at current density equals 60 mA cm(-2). The decay kinetics of o-nitrophenol follows a pseudo-first-order reaction. Aromatic intermediates such as catechol, resorcinol, 1,2,4-trihydroxybenzene, hydroquinone and benzoquinone and carboxylic acids such as maleic glycolic, malonic, glyoxilic and oxalic, have been identified and followed during the ONP treatment by chromatographic techniques. From these anodic oxidation by-products, a plausible reaction sequence for ONP mineralization on BDD anodes is proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Positive Biomechanical Effects of Titanium Oxide for Sandblasting Implant Surface as an Alternative to Aluminium Oxide.

    Science.gov (United States)

    Gehrke, Sergio Alexandre; Taschieri, Silvio; Del Fabbro, Massimo; Coelho, Paulo Guilherme

    2015-10-01

    The aim of this study was to evaluate the physico-chemical properties and the in vivo host response of a surface sandblasted with particles of titanium oxide (TiO2) followed by acid etching as an alternative to aluminium oxide. Thirty titanium disks manufactured in the same conditions as the implants and 24 conventional cylindrical implants were used. Half of the implants had a machined surface (Gcon) while in the other half; the surface was treated with particles of TiO2 followed by acid etching (Gexp). Surface characterization was assessed by scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), profilometry, and wettability. For the in vivo test, 12 implants of each group were implanted in the tibia of 6 rabbits, and were reverse torque tested after periods of 30 or 60 days after implantation. Following torque, SEM was utilized to assess residual bone-implant contact. The surface characterization by SEM showed a very homogeneous surface with uniform irregularities for Gexp and a small amount of residues of the blasting procedure, while Gcon presented a surface with minimal irregularities from the machining tools. Wettability test showed decreased contact angle for the Gcon relative to the Gexp. The Gexp removal torque at 30 and 60 days was 28.7%, and 33.2% higher relative to the Gcon, respectively. Blasting the surface with particles of TiO2 represents an adequate option for the surface treatment of dental implants, with minimal risk of contamination by the residual debris from the blasting procedure.

  1. Photocatalytic degradation of methyl orange dye by pristine titanium dioxide, zinc oxide, and graphene oxide nanostructures and their composites under visible light irradiation

    National Research Council Canada - National Science Library

    Ramesh Raliya; Caroline Avery; Sampa Chakrabarti; Pratim Biswas

    2017-01-01

    .... Degradation of an azo dye, methyl orange (MO), was tested in simulated wastewater with different oxide nanomaterials acting as photocatalysts under visible light. Titanium dioxide (TiO2), zinc oxide (ZnO...

  2. Self-Assembled Nanoporous Titania Layers on Ti Alloys by Anodic Oxidation%钛合金阳极氧化法制备自组装纳米多孔结构薄膜

    Institute of Scientific and Technical Information of China (English)

    张文彦; 李广忠; 奚正平; 张健; 汤慧萍; 汪强兵

    2012-01-01

    TiO2 nanotube arrays or nanoporous films fabricated by potentiostatic anodization of titanium (titanium alloy) in F-containing electrolytes constitute a material architecture that offers a large internal surface area and excellent electron percolation pathways for vectorial charge transfer between interfaces. The material architecture has proven to be of great interest for use in water photoelectrolysis, photocatalysis, heterojunction solar cells, and gas sensing. The parameters for TiO2 nanoporous film fabrication are found by changing the anodic oxidation voltage and phase composition of titanium alloys. When the anodization potential is below 30 V, TiO2 nanoporous film by anodizing TLM alloy aged at 550 °C for long time can be obtained%钛及钛合金在含有F-离子的电解液中阳极氧化,可自组装制备出有序TiO2纳米多孔或纳米管阵列薄膜,这类纳米阵列膜材料具有极大的内比表面积和优异的电子传输性能,可以用作纳米结构制备模板、高灵敏度传感器、染料敏化太阳能电池等.以TLM钛合金为阳极氧化的基片,通过改变阳极氧化电压、钛合金相结构,找到了制备纳米多孔阵列的参数,通过条件试验发现,在恒电压小于30 V时,经时效处理的TLM钛合金表面可以制备得到合金元素掺杂的TiO2纳米多孔结构薄膜.

  3. Auto-inhibition effects in anodic oxidation of phenols for electrochemical waste-water purification

    Directory of Open Access Journals (Sweden)

    B. E. CONWAY

    2001-12-01

    Full Text Available Removal or modification of noxious organic impurities in waste-waters is a major challenge for environmental science. Pollutants such as phenols and their derivatives, as well as PCBs, have attracted special attention. In recent years, the possibilities of effecting direct electrocatalytic oxidations at high-area electrodes such as supported Pt or RuO2 have been investigated. However, in a number of cases, especially with phenolic impurities, application of anodic oxidation fails to lead to continuous Faradaic oxidation currents owing to the electrode surfaces becoming blocked with polymeric oxidation products leading to auto-inhibition (“passivation” of the desired electrode process. Examples of such effects with phenols and related compounds are examined comparatively in the present paper by means of cyclic volatammetry and chronoamperometry.

  4. Rational design of metal oxide nanocomposite anodes for advanced lithium ion batteries

    Science.gov (United States)

    Li, Yong; Yu, Shenglan; Yuan, Tianzhi; Yan, Mi; Jiang, Yinzhu

    2015-05-01

    Metal-oxide anodes represent a significant future direction for advanced lithium ion batteries. However, their practical applications are still seriously hampered by electrode disintegration and capacity fading during cycling. Here, we report a rational design of 3D-staggered metal-oxide nanocomposite electrode directly fabricated by pulsed spray evaporation chemical vapor deposition, where various oxide nanocomponents are in a staggered distribution uniformly along three dimensions and across the whole electrode. Such a special design of nanoarchitecture combines the advantages of nanoscale materials in volume change and Li+/electron conduction as well as uniformly staggered and compact structure in atom migration during lithiation/delithiation, which exhibits high specific capacity, good cycling stability and excellent rate capability. The rational design of metal-oxide nanocomposite electrode opens up new possibilities for high performance lithium ion batteries.

  5. Methane Steam Reforming over an Ni-YSZ Solid Oxide Fuel Cell Anode in Stack Configuration

    Directory of Open Access Journals (Sweden)

    D. Mogensen

    2014-01-01

    Full Text Available The kinetics of catalytic steam reforming of methane over an Ni-YSZ anode of a solid oxide fuel cell (SOFC have been investigated with the cell placed in a stack configuration. In order to decrease the degree of conversion, a single cell stack with reduced area was used. Measurements were performed in the temperature range 600–800°C and the partial pressures of all reactants and products were varied. The obtained rates could be well fitted with a power law expression (r ∝PCH40.7. A simple model is presented which is capable of predicting the methane conversion in a stack configuration from intrinsic kinetics of the anode support material. The predictions are compared with the stack measurements presented here, and good agreement is observed.

  6. Synthesis and properties of iridescent Zn-containing anodic aluminum oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Xiaoxuan; Sun, Huiyuan, E-mail: huiyuansun@126.com; Liu, Lihu; Hou, Xue; Liu, Huiyuan

    2015-07-01

    A simple method of fabricating Zn-containing anodic aluminum oxide films for multifunctional anticounterfeit technology is reported. The resulting membranes were characterized with UV–vis illumination studies, natural light illumination color experiments, and electron microscopy analysis. Deposition of Zn in the nanopore region can enhance the color saturation of the thin alumina film with different colors dramatically. Both the anodization time and etching time have great influence on the structural color. The mechanisms for the emergence of this phenomenon are discussed and theoretical analysis further demonstrates the experimental results. - Highlights: • Iridescent PAA@Zn nanocomposite films were successfully fabricated. • A simple organics-assisted method is applied to making a series of fancy and multicolor patterns. • The color varies with the angle of incidence of the light used to view the film as is expected with Bragg–Snell formula. • Such colored films could be used in multifunctional anti-counterfeiting applications.

  7. Anodic oxides on InAlP formed in sodium tungstate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Suleiman, A. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: p.skeldon@manchester.ac.uk; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Echeverria, F. [Corrosion and Protection Group, University of Antioquia, Medellin (Colombia); Graham, M.J.; Sproule, G.I.; Moisa, S.; Quance, T. [Institute for Microstructural Sciences, National Research Council of Canada, Montreal Road, Ottawa K1A 0R6 (Canada); Habazaki, H. [Graduate Engineering School, Hokkaido University, N13 W8, Kita-ku, Sapporo 060-8628 (Japan)

    2010-02-15

    Amorphous anodic oxide films on InAlP have been grown at high efficiency in sodium tungstate electrolyte. The films are shown to comprise an outer layer containing indium species, an intermediate layer containing indium and aluminium species and an inner layer containing indium, aluminium and phosphorus species{sub .} The layering correlates with the influence on cation migration rates of the energies of In{sup 3+}-O, Al{sup 3+}-O and P{sup 5+}-O bonds, which increase in this order. The film surface becomes increasingly rough with increase of the anodizing voltage as pores develop in the film, which appear to be associated with generation of oxygen gas.

  8. Characterization of Anodic Aluminum Oxide Membrane with Variation of Crystallizing Temperature for pH Sensor.

    Science.gov (United States)

    Yeo, Jin-Ho; Lee, Sung-Gap; Jo, Ye-Won; Jung, Hye-Rin

    2015-11-01

    We fabricated electrolyte-dielectric-metal (EDM) device incorporating a high-k Al2O3 sensing membrane from a porous anodic aluminum oxide (AAO) using a two step anodizing process for pH sensors. In order to change the properties of the AAO template, the crystallizing temperature was varied from 400 degrees C to 700 degrees C over 2 hours. The structural properties were observed by field emission scanning electron microscopy (FE-SEM). The pH sensitivity increased with an increase in the crystallizing temperature from 400 degrees C to 600 degrees C. However at 700 degrees C, deformation occurred. The porous AAO sensor with a crystallizing temperature of 600 degrees C displayed the good sensitivity and long-term stability and the values were 55.7 mV/pH and 0.16 mV/h, respectively.

  9. Aluminum-doped zinc oxide as anode for organic near-infrared photodetectors

    Science.gov (United States)

    Wang, Xing; Fang, Fang; Su, Zisheng; Fang, Xuan; Zhang, Guang; Wang, Junbo; Wei, Zhipeng; Li, Jinhua; Wang, Xiaohua

    2014-08-01

    High transparency and low resistivity aluminum-doped zinc oxide (AZO) films were prepared by atomic layer deposition. The AZO films show a transparency of about 80% in the near-infrared (NIR) region and a resistivity of the order of 10-3 Ω cm. Organic small molecule NIR-photodetectors (NIR-PDs) with AZO as the anode have been demonstrated for the first time with lead phthalocyanine (PbPc) and C60 as the donor and acceptor, respectively. The optimized NIR-PD exhibited an external quantum efficiency of 6.2% at 760 nm. This result indicated that AZO can be used as the anode for high efficiency NIR-PDs.

  10. Sulfur Poisoning of the Water Gas Shift Reaction on Anode Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Hagen, Anke

    2013-01-01

    Investigation of fuels containing sulfur impurities is important regarding durability of solid oxide fuel cells (SOFC) because they are present in various potential fuels for SOFC applications. The effect of H2S in the ppm range on the performance of state-of-the-art anode supported SOFC at 850...... and 750°C is evaluated in either hydrogen/steam or hydrogen/steam/CO fuel. It was found that the poisoning effect is more severe in H2/H2O/CO vs. H2/H2O fuel. Only ∼8 ppm H2S can be allowed in the CO containing fuel without risking damage to the anode, whereas 90 ppm (or even more) is possible in H2/H2O...

  11. Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide

    KAUST Repository

    Baker, L. Robert

    2011-08-18

    The role of the oxide-metal interface in determining the activity and selectivity of chemical reactions catalyzed by metal particles on an oxide support is an important topic in science and industry. A proposed mechanism for this strong metal-support interaction is electronic activation of surface adsorbates by charge carriers. Motivated by the goal of using electronic activation to drive nonthermal chemistry, we investigated the ability of the oxide support to mediate charge transfer. We report an approximately 2-fold increase in the turnover rate of catalytic carbon monoxide oxidation on platinum nanoparticles supported on stoichiometric titanium dioxide (TiO2) when the TiO2 is made highly n-type by fluorine (F) doping. However, for nonstoichiometric titanium oxide (TiOX<2) the effect of F on the turnover rate is negligible. Studies of the titanium oxide electronic structure show that the energy of free electrons in the oxide determines the rate of reaction. These results suggest that highly n-type TiO2 electronically activates adsorbed oxygen (O) by electron spillover to form an active O- intermediate. © 2011 American Chemical Society.

  12. Synthesis of anodic titania nanotubes in Na{sub 2}SO{sub 4}/NaF electrolyte: A comparison between anodization time and specimens with biomaterial based approaches

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, M., E-mail: blkrish88@gmail.com [Department of Metallurgical Engineering, PSG College of Technology, Coimbatore 641 004 (India); Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Narayanan, R. [Department of Metallurgical Engineering, PSG College of Technology, Coimbatore 641 004 (India); Department of Mechanical Engineering, Saveetha School of Engineering, Chennai 602 105 (India)

    2013-07-01

    Surface modification of commercially pure titanium (cp-Ti) has been carried out by electrochemical anodic oxidation at constant voltage for different time periods (0.5, 1, 2 and 4.5 h). Currents developed during the anodization indicate that the nanotubes are formed due to the competition of titania formation and dissolution under the assistance of electric field. Topologies of the anodized titanium change remarkably with time of oxidation. The morphology of the as-prepared nanotubes was characterized by scanning electron microscopy and atomic force microscopy while the chemistry and crystallinity were characterized by energy-dispersive X-ray spectroscopy and X-ray diffraction respectively. The as-anodized oxide was of amorphous but transformed to anatase and/or rutile crystal structure upon annealing for 3 h at 600 °C. The anatase structure showed excellent apatite-forming ability and produced a compact apatite layer covering the surface completely upon treatment in simulated body fluid (SBF) solution for 30 h. Corrosion of anodized titanium samples was studied in a SBF solution using open circuit potential, polarization and electrochemical impedance measurements and compared with that of non-oxidized titanium. Among these samples, titanium anodized for 4.5 h exhibited superior corrosion properties. - Highlights: • We synthesized TiO{sub 2} nanotubes by anodization in Na{sub 2}SO{sub 4}/NaF electrolyte. • Topologies of the anodized titanium change remarkably with oxidation time. • We studied surface morphologies of TiO{sub 2} nanotubes. • TiO{sub 2} nanotubes show superior corrosion resistance.

  13. Electropolymerization of polyaniline on titanium oxide nanotubes for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Mujawar, Sarfraj H.; Ambade, Swapnil B.; Battumur, T.; Ambade, Rohan B. [Organic Optoelectronic Materials Laboratory, Division of Semiconductor and Chemical Engineering, Nanomaterials Processing Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lee, Soo-Hyoung, E-mail: shlee66@chonbuk.ac.k [Organic Optoelectronic Materials Laboratory, Division of Semiconductor and Chemical Engineering, Nanomaterials Processing Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2011-04-30

    Highlights: {yields} Polyaniline (PANI)-Titanium nanotube template (TNT) composite for supercapacitors. {yields} The mechanism of the controlled growth of hollow open ended PANI nanotubes using a TNT template is studied. {yields} A rare effort to electropolymerise PANI on TNTs resulting into an appreciable capacitance of 740 F g{sup -1}. - Abstract: Vertically aligned polyaniline (PANI) nanotubes have great potential application in supercapacitor electrode material. In this paper we have investigated facile growth of PANI nanotubes on a titanium nanotube template (TNT) using electrochemical polymerization. The morphology of PANI nanostructures grown over TNT is strongly influenced by the scan rate in the electrochemical polymerization. The growth morphology of PANI nanotubes has been carefully analyzed by field emission scanning electron microscopy. The detailed growth mechanism of PANI nanotubes has been put forward. Specific capacitance value of 740 F g{sup -1} was obtained for PANI nanotube structures (measured at charge-discharge rate of 3 A g{sup -1}).

  14. Phenotypic and genomic responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis germinants

    Science.gov (United States)

    The effects of exposure to two nanoparticles (NPs) -titanium dioxide (nano-titania) and cerium oxide (nano-ceria) at 500 mg NPs L-1 on gene expression and growth in Arabidopsis thaliana germinants were studied using microarrays and phenotype studies. After 12 days post treatment,...

  15. Ion pair formation and primary charging behavior of titanium oxide (anastase and rutile)

    NARCIS (Netherlands)

    Bourikas, K.; Hiemstra, T.; Riemsdijk, van W.H.

    2001-01-01

    The primary charging behavior of titanium oxide (anatase, rutile, and P25) and the ion pair formation of the electrolyte ions with the surface groups have been extensively studied. A large number of titration and electrokinetic data sets available in the literature have been successfully described,

  16. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  17. Lysozyme-mediated biomineralization of titanium-tungsten oxide hybrid nanoparticles with high photocatalytic activity.

    Science.gov (United States)

    Kim, Jung Kyu; Jang, Ji-ryang; Choi, Noori; Hong, Dahyun; Nam, Chang-Hoon; Yoo, Pil J; Park, Jong Hyeok; Choe, Woo-Seok

    2014-10-21

    Titanium-tungsten oxide composites with greatly enhanced photocatalytic activity were synthesized by lysozyme-mediated biomineralization. It was shown for the first time that simple control of the onset of biomineralization could enable fine tuning of the composition and crystallinity of the composites to determine their photocatalytic performance.

  18. Calcium-doped ceria materials for anode of solid oxide fuel cells running on methane fuel

    Science.gov (United States)

    Zhao, Kai; Du, Yanhai

    2017-04-01

    A calcium-doped ceria with nominal compositions of Ce1-xCaxO2-δ (0.00 ≤ x ≤ 0.30) has been developed as an anode component for solid oxide fuel cells running on methane fuel. Crystal phases of Ce1-xCaxO2-δ are investigated with respect to the amount of calcium dopant. The Ce1-xCaxO2-δ shows single fluorite phase when the calcium is within 15 mol.%, and higher calcium doping levels lead to the appearance of a secondary phase (CaO). Conductivities of Ce1-xCaxO2-δ ceramics are studied by a four-probe method in air and the composition of Ce0.9Ca0.1O2-δ (x = 0.10) is found exhibiting the highest conductivity among the samples investigated in this work. Electrocatalytic properties of Ce0.9Ca0.1O2-δ are evaluated based on Ni-Ce1-xCaxO2-δ anode supported single cell running on methane fuel. At 800 °C, the single cell with Ni-Ce0.9Ca0.1O2-δ (x = 0.10) anode exhibits an optimum maximum powder density (618 mW cm-2) and good performance stability during 30 h operation in methane fuel. The promising findings substantiate the good performance of Ni-Ce0.9Ca0.1O2-δ anode for electrochemical oxidation of methane fuel.

  19. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    Energy Technology Data Exchange (ETDEWEB)

    Anil V. Virkar

    2001-09-26

    Anode-supported solid oxide fuel cells with Ni + yttria-stabilized zirconia (YSZ) anode, YSZ-samaria-doped ceria (SDC) bi-layer electrolyte and Sr-doped LaCoO{sub 3} (LSC) + SDC cathode were fabricated. Fuel used consisted of H{sub 2} diluted with He, N{sub 2}, H{sub 2}O or CO{sub 2}, mixtures of H{sub 2} and CO, and mixtures of CO and CO{sub 2}. Cell performance was measured at 800 C with above-mentioned fuel gas mixtures and air as oxidant. For a given concentration of the diluent, the cell performance was higher with He as the diluent than with N{sub 2} as the diluent. Mass transport through porous Ni-YSZ anode for H{sub 2}-H{sub 2}O, CO-CO{sub 2} binary systems and H{sub 2}-H{sub 2}O-diluent gas ternary systems was analyzed using multicomponent gas diffusion theory. At high concentrations of the diluent, the maximum achievable current density was limited by the anodic concentration polarization. From this measured limiting current density, the corresponding effective gas diffusivity was estimated. Highest effective diffusivity was estimated for fuel gas mixtures containing H{sub 2}-H{sub 2}O-He mixtures ({approx}0.34 cm{sup 2}/s), and the lowest for CO-CO{sub 2} mixtures ({approx}0.07 cm{sup 2}/s). The lowest performance was observed with CO-CO{sub 2} mixture as a fuel, which in part was attributed to the lowest effective diffusivity of the fuels tested.

  20. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E., E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: souzajulio@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2009-07-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  1. Surface Modification of Porous Titanium Granules for Improving Bioactivity.

    Science.gov (United States)

    Karaji, Zahra Gorgin; Houshmand, Behzad; Faghihi, Shahab

    The highly porous titanium granules are currently being used as bone substitute material and for bone tissue augmentation. However, they suffer from weak bone bonding ability. The aim of this study was to create a nanostructured surface oxide layer on irregularly shaped titanium granules to improve their bioactivity. This could be achieved using optimized electrochemical anodic oxidation (anodizing) and heat treatment processes. The anodizing process was done in an ethylene glycol-based electrolyte at an optimized condition of 60 V for 3 hours. The anodized granules were subsequently annealed at 450°C for 1 hour. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) were used to characterize the surface structure and morphology of the granules. The in vitro bioactivity of the samples was evaluated by immersion of specimens in simulated body fluid (SBF) for 1, 2, and 3 weeks. The human osteoblastic sarcoma cell line, MG63, was used to evaluate cell viability on the samples using dimethylthiazol-diphenyl tetrazolium bromide (MTT) assay. The results demonstrated the formation of amorphous nanostructured titanium oxide after anodizing, which transformed to crystalline anatase and rutile phases upon heat treatment. After immersion in SBF, spherical aggregates of amorphous calcium phosphate were formed on the surface of the anodized sample, which turned into crystalline hydroxyapatite on the surface of the anodized annealed sample. No cytotoxicity was detected among the samples. It is suggested that anodic oxidation followed by heat treatment could be used as an effective surface treatment procedure to improve bioactivity of titanium granules implemented for bone tissue repair and augmentation.

  2. Anodic oxidation of salicylic acid on BDD electrode: Variable effects and mechanisms of degradation

    Energy Technology Data Exchange (ETDEWEB)

    Rabaaoui, Nejmeddine, E-mail: chimie_tunisie@yahoo.fr [Faculte des Sciences de Sfax, Departement de Chimie, 3038 Sfax (Tunisia); Allagui, Mohamed Salah [Faculte des Sciences de Gafsa, Campus Universitaire Sidi Ahmed Zarrouk, 2112 Gafsa (Tunisia)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Oxidation with BDD is a powerful electrochemical method able to mineralize. Black-Right-Pointing-Pointer SA is oxidized to aromatic compounds then CO{sub 2} and H{sub 2}O. Black-Right-Pointing-Pointer Polymeric intermediate products were formed. - Abstract: The degradation of 100 mL of solution with salicylic acid (SA) in the pH range 3.0-10.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a stainless steel cathode, both of 3 cm{sup 2} area, by applying a current of 100, 300 and 450 mA at 25 Degree-Sign C. Completed mineralization is always achieved due to the great concentration of hydroxyl radical ({center_dot}OH) generated at the BDD surface. The mineralization rate increases with increasing applied current, but decreases when drug concentration rises from 200 mg L{sup -1}. Nevertheless, the pH effect was not significant. During oxidation it was observed that catechol, 2,5-dihydroxylated benzoic acid, 2,3-dihydroxylated benzoic acid and hydroquinone were formed as aromatic intermediates. In addition, ion-exclusion chromatography allowed the detection of fumaric, maleic, oxalic and formic as the ultimate carboxylic acid.

  3. Effect of Anodisation Parameters on the Formation of Porous Anodic Oxide on Ti, Zr and W

    Energy Technology Data Exchange (ETDEWEB)

    Lockman, Zainovia; Ismail, Syahriza; Razak, Khairunisak Abdul; Lee, Lim Shu, E-mail: zainovia@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2011-02-15

    Ti, Zr and W foils were anodized in 85% glycerol + 15% water electrolyte added to it 0.5wt%NH{sub 4}F (pH {approx} 6) at 20V. Self-ordered nanotubular oxide structure was found on Ti and Zr whereas oxide on W is comprised of dual layer with compact inner layer and oxide precipitates as the outer layer. The mechanism of the formation of the nanotubes is discussed. The formation of bi-layer on W is attributed to the high degree of dissolution and precipitation of WO{sub 3} on the surface of the anodic oxide in the viscous glycerol solution. In aqueous bath, the precipitation is much reduced revealing WO{sub 3} with a more ordered porous structure. On Zr foil nanotubes formed are much smaller than on Ti with diameter of < 40 nm compared to 100 nm on Ti. The length of the nanotubes is in the range of 1-2({mu}m for both zirconia and titania nanotubes. Increasing the voltage increases the diameter of the nanotubes marginally and there exists a maximum voltage which could be applied on the foils before the nanotubular structure is destroyed. In 85% glycerol, the voltage must be kept at < 30V for both samples.

  4. Effect of Anodisation Parameters on the Formation of Porous Anodic Oxide on Ti, Zr and W

    Science.gov (United States)

    Lockman, Zainovia; Ismail, Syahriza; Razak, Khairunisak Abdul; Shu Lee, Lim

    2011-02-01

    Ti, Zr and W foils were anodized in 85% glycerol + 15% water electrolyte added to it 0.5wt%NH4F (pH ~ 6) at 20V. Self-ordered nanotubular oxide structure was found on Ti and Zr whereas oxide on W is comprised of dual layer with compact inner layer and oxide precipitates as the outer layer. The mechanism of the formation of the nanotubes is discussed. The formation of bi-layer on W is attributed to the high degree of dissolution and precipitation of WO3 on the surface of the anodic oxide in the viscous glycerol solution. In aqueous bath, the precipitation is much reduced revealing WO3 with a more ordered porous structure. On Zr foil nanotubes formed are much smaller than on Ti with diameter of nanotubes is in the range of 1-2(μm for both zirconia and titania nanotubes. Increasing the voltage increases the diameter of the nanotubes marginally and there exists a maximum voltage which could be applied on the foils before the nanotubular structure is destroyed. In 85% glycerol, the voltage must be kept at < 30V for both samples.

  5. Novel Size and Surface Oxide Effects in Silicon Nanowires as Lithium Battery Anodes

    KAUST Repository

    McDowell, Matthew T.

    2011-09-14

    With its high specific capacity, silicon is a promising anode material for high-energy lithium-ion batteries, but volume expansion and fracture during lithium reaction have prevented implementation. Si nanostructures have shown resistance to fracture during cycling, but the critical effects of nanostructure size and native surface oxide on volume expansion and cycling performance are not understood. Here, we use an ex situ transmission electron microscopy technique to observe the same Si nanowires before and after lithiation and have discovered the impacts of size and surface oxide on volume expansion. For nanowires with native SiO2, the surface oxide can suppress the volume expansion during lithiation for nanowires with diameters <∼50 nm. Finite element modeling shows that the oxide layer can induce compressive hydrostatic stress that could act to limit the extent of lithiation. The understanding developed herein of how volume expansion and extent of lithiation can depend on nanomaterial structure is important for the improvement of Si-based anodes. © 2011 American Chemical Society.

  6. Iron oxide-decorated carbon for supercapacitor anodes with ultrahigh energy density and outstanding cycling stability.

    Science.gov (United States)

    Guan, Cao; Liu, Jilei; Wang, Yadong; Mao, Lu; Fan, Zhanxi; Shen, Zexiang; Zhang, Hua; Wang, John

    2015-05-26

    Supercapacitor with ultrahigh energy density (e.g., comparable with those of rechargeable batteries) and long cycling ability (>50000 cycles) is attractive for the next-generation energy storage devices. The energy density of carbonaceous material electrodes can be effectively improved by combining with certain metal oxides/hydroxides, but many at the expenses of power density and long-time cycling stability. To achieve an optimized overall electrochemical performance, rationally designed electrode structures with proper control in metal oxide/carbon are highly desirable. Here we have successfully realized an ultrahigh-energy and long-life supercapacitor anode by developing a hierarchical graphite foam-carbon nanotube framework and coating the surface with a thin layer of iron oxide (GF-CNT@Fe2O3). The full cell of anode based on this structure gives rise to a high energy of ∼74.7 Wh/kg at a power of ∼1400 W/kg, and ∼95.4% of the capacitance can be retained after 50000 cycles of charge-discharge. These performance features are superior among those reported for metal oxide based supercapacitors, making it a promising candidate for the next generation of high-performance electrochemical energy storage.

  7. Electrochemical oxidation of biological pretreated and membrane separated landfill leachate concentrates on boron doped diamond anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Bo, E-mail: 357436235@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Yu, Zhiming, E-mail: zhiming@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Wei, Qiuping, E-mail: qiupwei@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Long, HangYu, E-mail: 55686385@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Xie, Youneng, E-mail: 1187272844@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Wang, Yijia, E-mail: 503630433@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2016-07-30

    Highlights: • High quality boron-doped diamond film electrodes were synthesized on Nb substrates. • Electrochemical oxidation on boron-doped diamond anode is an effective method for treating landfill leachate concentrates. • Optimal operating conditions for electrochemical oxidation of landfill leachate concentrates is determined. • 87.5% COD removal and 74.06% NH{sub 3}−N removal were achieved after 6 h treatment. - Abstract: In the present study, the high quality boron-doped diamond (BDD) electrodes with excellent electrochemical properties were deposited on niobium (Nb) substrates by hot filament chemical vapor deposition (HFCVD) method. The electrochemical oxidation of landfill leachate concentrates from disc tube reverse osmosis (DTRO) process over a BDD anode was investigated. The effects of varying operating parameters, such as current density, initial pH, flow velocity and cathode material on degradation efficiency were also evaluated following changes in chemical oxygen demand (COD) and ammonium nitrogen (NH{sub 3}−N). The instantaneous current efficiency (ICE) was used to appraise different operating conditions. As a result, the best conditions obtained were as follows, current density 50 mA cm{sup −2}, pH 5.16, flow velocity 6 L h{sup −1}. Under these conditions, 87.5% COD and 74.06% NH{sub 3}−N removal were achieved after 6 h treatment, with specific energy consumption of 223.2 kWh m{sup −3}. In short, these results indicated that the electrochemical oxidation with BDD/Nb anode is an effective method for the treatment of landfill leachate concentrates.

  8. Growth Mechanism of γ-MnS Nanorod-Arrays by Hydrothermal Method on Anodic Aluminum Oxide Template

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jianming; Liu, Weifeng; Lv, Yong; Yao, Lianzeng [Chinese Academy of Science, Hefei, Anhui (China)

    2010-09-15

    Hydrothermal method is a general, low-cost and convenience method which was utilized for synthesis of nanomaterials. Our research group has reported that oriented MnS nanorods on anodic aluminum oxide template were synthesized under a hydrothermal condition and demonstrated the effect of precursor content on the morphology evolution of as-samples. In order to research the growth mechanism of the arrays, herein we synthesized MnS nanorod arrays by combination of anodic aluminum oxide template and hydrothermal method on different substrates. Through-hole anodic aluminum oxide templates were prepared using Al foil (99.999%) via a two-step anodization process as described in literature. To investigate the effect of different substrates on the morphology of the-products, different substrates including anodic aluminum oxide template (sample A), one-step anodization Al foil (sample B, which was prepared by first anodizing Al foil for 10h and then removing the alumina layer with the mixed acid (0.6 M H{sub 3}PO{sub 4} and 0.15 M H{sub 2}CrO{sub 4}), where the foil still kept the close-packed concave nano-pits consistently with the nanopole of anodic aluminum oxide template), Al foil (sample C, dipped in HNO{sub 3} solution and covered by a compact alumina layer), Si wafer (sample D) respectively were put into Teflon-lined stainless steel autoclaves of 20 mL capacity filled with 16 mL mixed solution consisting of 2 mol/L MnCl{sub 4} and 2 mol/L thiourea. We kept the reaction at 150 .deg. C for 20 h. When reactions completed the products were washed three times with distilled water and absolute ethanol, respectively. Then the products were dried in an oven at 60 .deg. C.

  9. Features Of The Phase Transformations In Titanium-containing Zinc Aluminosilicate Glasses Doped With Cobalt Oxide

    OpenAIRE

    Alekseeva I.P.; Dymshits O.S.; Ermakov V.A.; Zhilin A.A.; Tsenter M.Ya.

    2013-01-01

    We demonstrated the efficiency of the Raman spectroscopy method in the study of the process of the formation of the amorphous zinc aluminotitanate (ZAT) phase during the phase decomposition of the titanium-containing zinc aluminosilicate glasses doped with cobalt oxide. The quantitative dependences of the variation of the intensity of the Raman bands characteristic for amorphous and crystalline phases on the temperature of the thermal treatment and the cobalt oxide concentration have been obt...

  10. Anticoagulation and endothelial cell behaviors of heparin-loaded graphene oxide coating on titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Chang-Jiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Pang, Li-Qun [Department of General Surgery, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an 223300 (China); Gao, Fei [Zhejiang Zylox Medical Devices Co., Ltd., Hangzhou 310000 (China); Wang, Ya-Nan; Liu, Tao; Ye, Wei; Hou, Yan-Hua [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

    2016-06-01

    Owing to its unique physical and chemical properties, graphene oxide (GO) has attracted tremendous interest in many fields including biomaterials and biomedicine. The purpose of the present study is to investigate the endothelial cell behaviors and anticoagulation of heparin-loaded GO coating on the titanium surface. To this end, the titanium surface was firstly covered by the polydopamine coating followed by the deposition of the GO coating. Heparin was finally loaded on the GO coating to improve the blood compatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that the heparin-loaded GO coating was successfully created on the titanium surface. The scanning electron microscopy (SEM) images indicated that a relative uniform GO coating consisting of multilayer GO sheets was formed on the substrate. The hydrophilicity of the titanium surface was enhanced after the deposition of GO and further improved significantly by the loading heparin. The GO coating can enhance the endothelial cell adhesion and proliferation as compared with polydopamine coating and the blank titanium. Loading heparin on the GO coating can significantly reduce the platelet adhesion and prolong the activated partial thromboplastin time (APTT) while not influence the endothelial cell adhesion and proliferation. Therefore, the heparin-loaded GO coating can simultaneously enhance the cytocompatibility to endothelial cells and blood compatibility of biomaterials. Because the polydopamine coating can be easily prepared on most of biomaterials including polymer, ceramics and metal, thus the approach of the present study may open up a new window of promising an effective and efficient way to promote endothelialization and improve the blood compatibility of blood-contact biomedical devices such as intravascular stents. - Highlights: • Heparin-loaded graphene oxide coating was

  11. pH effect on the potentiodynamic behaviour of titanium electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, M.W.; Abdel Rahim, M.A. (Cairo Univ., Gizeh (Egypt). Dept. of Chemistry)

    1991-07-01

    Potentiodynamic measurements on mechanically polished titanium electrodes were performed in different solutions in the pH range 0.55-12. Two anodic peaks and one small cathodic peak were observed. Comparison with thermodynamic data revealed the possibility of formation of Ti{sub 2}O{sub 3} or TiO{sub 2} at potentials corresponding to the first anodic peak probably directly from titanium hydride. The second anodic peak is interpreted as the oxidation of incorporated H to form H{sup +} ions which partly remain inside the metal. The small cathodic peak represents the back reduction of the incorporated H{sup +} to the metal hydride. (orig.).

  12. Opportunities in the electrowinning of molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  13. A new microplatform based on titanium dioxide nanofibers/graphene oxide nanosheets nanocomposite modified screen printed carbon electrode for electrochemical determination of adenine in the presence of guanine.

    Science.gov (United States)

    Arvand, Majid; Ghodsi, Navid; Zanjanchi, Mohammad Ali

    2016-03-15

    The current techniques for determining adenine have several shortcomings such as high cost, high time consumption, tedious pretreatment steps and the requirements for highly skilled personnel often restrict their use in routine analytical practice. This paper describes the development and utilization of a new nanocomposite consisting of titanium dioxide nanofibers (TNFs) and graphene oxide nanosheets (GONs) for screen printed carbon electrode (SPCE) modification. The synthesized GONs and TNFs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The modified electrode (TNFs/GONs/SPCE) was used for electrochemical characterization of adenine. The TNFs/GONs/SPCE exhibited an increase in peak current and the electron transfer kinetics and decrease in the overpotential for the oxidation reaction of adenine. Using differential pulse voltammetry (DPV), the prepared sensor showed good sensitivity for determining adenine in two ranges from 0.1-1 and 1-10 μM, with a detection limit (DL) of 1.71 nM. Electrochemical studies suggested that the TNFs/GONs/SPCE provided a synergistic augmentation on the voltammetric behavior of electrochemical oxidation of adenine, which was indicated by the improvement of anodic peak current and a decrease in anodic peak potential. The amount of adenine in pBudCE4.1 plasmid was determined via the proposed sensor and the result was in good compatibility with the sequence data of pBudCE4.1 plasmid.

  14. Clean forming of stainless steel and titanium products by lubricious oxides

    DEFF Research Database (Denmark)

    Heikkilä, Irma; Wadman, Boel; Thoors, Håkan

    2012-01-01

    Big social benefits can be attained through increased use of stainless steel or titanium in new sheet metal applications. Unfortunately, forming of these materials is often a challenging and costly operation, that can lead to environmental and health problems when solving the technical limitations...... to industrial forming processes. Preliminary evaluations show a beneficial influence of two oxides types, on stainless steel and on titanium. More work is needed to test the lubricating effect in other forming operations and to analyse the sustainability aspects for products manufactured with this alternative...

  15. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    Energy Technology Data Exchange (ETDEWEB)

    Professor Anil V. Virkar

    2003-05-23

    This report summarizes the work done during the entire project period, between October 1, 1999 and March 31, 2003, which includes a six-month no-cost extension. During the project, eight research papers have, either been, published, accepted for publication, or submitted for publication. In addition, several presentations have been made in technical meetings and workshops. The project also has provided support for four graduate students working towards advanced degrees. The principal technical objective of the project was to analyze the role of electrode microstructure on solid oxide fuel cell performance. Prior theoretical work conducted in our laboratory demonstrated that the particle size of composite electrodes has a profound effect on cell performance; the finer the particle size, the lower the activation polarization, the better the performance. The composite cathodes examined consisted of electronically conducting perovskites such as Sr-doped LaMnO{sub 3} (LSM) or Sr-doped LaCoO{sub 3} (LSC), which is also a mixed conductor, as the electrocatalyst, and yttria-stabilized zirconia (YSZ) or rare earth oxide doped CeO{sub 2} as the ionic conductor. The composite anodes examined were mixtures of Ni and YSZ. A procedure was developed for the synthesis of nanosize YSZ by molecular decomposition, in which unwanted species were removed by leaching, leaving behind nanosize YSZ. Anode-supported cells were made using the as-synthesized powders, or using commercially acquired powders. The electrolyte was usually a thin ({approx}10 microns), dense layer of YSZ, supported on a thick ({approx}1 mm), porous Ni + YSZ anode. The cathode was a porous mixture of electrocatalyst and an ionic conductor. Most of the cell testing was done at 800 C with hydrogen as fuel and air as the oxidant. Maximum power densities as high as 1.8 W/cm{sup 2} were demonstrated. Polarization behavior of the cells was theoretically analyzed. A limited amount of cell testing was done using liquid

  16. The impact of NiO on microstructure and electrical property of solid oxide fuel cell anode

    Institute of Scientific and Technical Information of China (English)

    LI Yan; LUO Zhong-yang; YU Chun-jiang; LUO Dan; XU Zhu-an; CEN Ke-fa

    2005-01-01

    Ni-Ce0.8Sm0.2O1.9 (Ni-SDC) cermet was selected as anode material for reduced temperature (800 ℃) solid oxide fuel cells in this study. The influence of NiO powder fabrication methods for Ni-SDC cermets on the electrode performance was investigated so that the result obtained can be applied to make high-quality anode. Three kinds of NiO powder were synthesized with a fourth kind being available in the market. Four types of anode precursors were fabricated with these NiO powders and Ce0.sSm0.2O1.9 (SDC), and then were reduced to anode wafers for sequencing measurement. The electrical conductivity of the anodes was measured and the effect ofmicrostructure was investigated. It was found that the anode electrical conductivity depends strongly on the NiO powder morphologies, microstructure of the cermet anode and particle sizes, which are decided by NiO powder preparation technique. The highest electrical conductivity is obtained for anode cermets with NiO powder synthesized by NiCO3·2Ni(OH)2.4H2O or Ni(NO3)2.6H2O decomposition technique.

  17. Production of planar copper-based anode supported intermediate temperature solid oxide fuel cells cosintered at 950 °C

    Science.gov (United States)

    De Marco, Vincenzo; Grazioli, Alberto; Sglavo, Vincenzo M.

    2016-10-01

    Copper-based anode supported planar Intermediate Temperature Solid Oxide Fuel Cells are produced and characterized in the present work. The most important advancement is related to the use of copper within the anodic layer, this giving promising results for feeding Intermediate Temperature Solid Oxide Fuel Cells with carbon and sulphur containing fuels. Both anode and Li2O containing-Gadolinia Doped Ceria based electrolyte are produced by water based tape casting process. The supporting anode is coupled to the electrolyte by thermopressing, the cathode being obtained by screen printing. A 3 h isotherm at 950 °C allows to obtain the cosintering of the three layers. The electrochemical test performed on such cells reveals a 0.8 V open circuit voltage and a power density higher than 26 mW cm-2 at 650 °C.

  18. Nickel/Yttria-stabilised zirconia cermet anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Primdahl, S.

    1999-08-01

    This thesis deals with the porous Ni/yttria-stabilized zirconia (YSZ) cermet anode on a YSZ electrolyte for solid oxide fuel cells (SOFC). Such anodes are predominantly operated in moist hydrogen at 700 deg. C to 1000 deg. C, and the most important technological parameters are the polarization resistance and the long-term stability. The polarization resistance can be measured by a number of techniques, in the present work impedance spectroscopy has been used extensively. By impedance spectroscopy limiting processes in the anode polarization resistance may often be separated and characterized individually, provided they have a reasonable separation in time constants. Three limiting processes are recognized in impedance spectra obtained on technological Ni/YSZ cermet anodes characterized against a stable reference electrode atmosphere. By parameter studies and illustrative experiments, the two contributions at low and medium frequency have been identified as gas conversion and diffusion limitations, respectively. Both of these effects are concentration limitations relating to the inefficient exchange of fuel gas in the test setup outside the porous cermet. A test setup geometry where these concentration effects are avoided for high-performance electrodes is recommended. The high frequency limitation is demonstrated to relate to the cermet structure. The dependence on gas composition, temperature, adsorbed species (sulfur), isotopes (H/D), sintering temperature and cermet thickness is investigated. Despite these studies and several similar studies by others, the exact chemical or physical nature of the limiting step has not been incontestably identified. However, these is a general consensus in literature about the hydrogen oxidation process taking place on or near to the triple phase boundary (TPB) line, where open gas-filled pores, the continuous electrolyte phase (oxide ion cunductor) and the continuous Ni phase (electronic conductor) meet. The physical thickness

  19. Destination of organic pollutants during electrochemical oxidation of biologically-pretreated dye wastewate