Ti Plate Research Articles

Photoreduction of CO2 using black TiO2 films under solar light

Black TiO2 films with unique porous structures have been successfully obtained in-situ on Ti plates by a simple hydrothermal treatment using H2O2 solution. The samples were used as photocatalysts to reduce CO2 under simulated sunlight irradiation at room temperature in the presence of H2O. The films have excellent grid-like structures providing more active photocatalysis sites and exhibit extremely high CO2 photoreduction efficiency with favourable selective formation of CO and CH4 (with highest production rates of 115 and 12μmol/gh, respectively) compared to conventional TiO2 (Degussa P25) (0.28 and 0.019μmol/gh, respectively). The structural deviation from standard crystalline anatase with the existence of substantial Ti3+ and oxygen vacancies is the critical factor for expanding the absorbance of TiO2 into the visible light region and the resulting excellent photocatalytic performance under simulated sunlight irradiation.

The Controllable Growth of Stereo Reticular Hydroxyapatite Structure on Femtosecond Lasers Micro-Patterned Titanium Surface

The controllable deposition of hydroxyapatite (HA) on femtosecond lasers micro-patterned Titanium (Ti) plates was studied in simulated body fluid (SBF). Energy Dispersive Spectrometer analysis and X-ray Diffraction (XRD) analysis show that the hydroxyapatite deposites on the pattened titanium surface in 1.5 SBF and SEM studies show three growth modes of HA (homogeneous hydroxyapatite layer, needle-like structure, and plate-like structure) deposited at different spots of the Ti plate surface. This stereo reticular structure of hydroxyapatite could be regarded as promising candidate material for metal implantation.

Friction behavior of network-structured CNT coating on pure titanium plate

Friction behavior of the network-structured CNTs coated pure Ti plate was evaluated by ball-on-disk wear test using SUS304 ball specimen under dry condition. The friction coefficient was significantly low and stable compared to the as-received Ti plate with no coating film. CNTs coating film had two important roles; self-lubrication and bearing effects to reduce the friction coefficient and carbon solid-solution hardening to improve the abrasive wear property of Ti plate. The annealing treatment at higher temperature (1123K) was more effective to reduce the friction coefficient than that at lower temperature (973K) because the Ti plate surface was uniformly covered with CNTs film even after sliding wear test. This is due to TiC interlayer formation via a reaction between Ti plate and carbon elements originated from CNTs during annealing. As a result, a strong interface bonding between CNTs film and Ti plate surface was obtained by higher temperature annealing treatment, and obstructed the detachment of CNTs film during wear test.

Electrochemical removal of Reactive Black 5 azo dye using non-commercial boron-doped diamond film anodes

Although various processes for the removal of Reactive Black 5 (RB5) dye from textile wastewater have been studied, the degradation pathway of RB5 on boron-doped diamond (BDD) films has not been elucidated. We here report the efficient electro-oxidation of RB5 in aqueous solution using BDD/Ti electrodes and we propose a degradation route based on intermediates and byproducts identified by high performance liquid chromatography-mass spectrometry. BDD films doped with 5000 or 15,000ppm of B were grown on Ti plates using the hot filament chemical vapor technique to produce electrodes E1 and E2, respectively. Films were evaluated by scanning electron microscopy, X-ray diffraction and Raman spectroscopy before and after several hours of electrolysis and were shown to be of high quality and stability. Total removal of color from RB5 solution was achieved with either electrode by electrolysis at low current density (50mAcm−2). Total mineralization of the dye solution could be attained with electrode E2 at an applied current density of 100mAcm−2. Under these conditions, 91% of the chromatographic area associated with RB5 (monitored at 311nm) was removed, thereby verifying cleavage of the aromatic rings of the dye. Furthermore decolorization of RB5 followed pseudo zero-order kinetics with both electrodes and the apparent rate constant was higher with electrode E2. The results obtained indicate that BDD/Ti is a promising material for the electro-degradation of RB5 since aromatic rings and chromophoric groups were ruptured during electrolysis to generate aliphatic compounds, such as oxalic acid, that can be easily converted into CO2.

Crack propagation of Ti alloy via adiabatic shear bands

This study was focused on the characterization of the origin and mechanism of crack propagation as a result of hot induction bending of Ti alloy. Plates of Ti–6Al–4V alloy with 12.5mm of thickness were submitted to hot induction bending below the beta transus temperature. Optical and scanning electron microscopy analysis showed crack formation in the tensile zone. Microstructural evidence showed that cracks propagate through the adiabatic shear bands by Dimple-Void mechanism. However, voids formation before shear banding also occurred. In both mechanisms adiabatic shear bands are formed via dynamic recrystallization where the alpha–beta interphase works as stress concentrator promoting the formation of dimples and voids.

Titania nanotube/nano-brushite composited bioactive coating with micro/nanotopography on titanium formed by anodic oxidation and hydrothermal treatment

This work was to improve the bioactivity of biomedical titanium (Ti) through constructing a bioactive surface with micro/nano-topography on Ti. Firstly, Ti plates were sandblasted, acid etched and anodized (SBAO) to obtain the controlled micro/nano-topography. And then, heat treatment was used to change the amorphous phase of Ti oxide nanotubes to anatase on the SBAO sample. The SBAO sample and heat treated SBAO sample (SBAOT) both have super hydrophilicity mainly due to their micro/nano-topography. At last, nano-brushite was deposited on the SBAOT surface by hydrothermal treatment to further improve its bioactivity. The simulated body fluid incubation indicated that this novel coating with nano-brushite has more excellent bioactivity as compared to Ti, and SBAO and SBAOT.

Effect of ZrO2 Additive for IrO2-Ta2O5/Ti on Activity of Oer in Sulfuric Acid with Toluene Contamination

Introduction In order to promote the introduction of renewable energy, large-scale energy storage and transportation systems are required. Hydrogen is expected to apply for the energy storage and transportation. Organic chemical hydride materials are prospective energy carriers to solve the issue of hydrogen’s low volumetric energy density. Among them, toluene (TL)/methylcyclohexane (MCH) system has been focused due to the easy handling and the low toxicity. Recently, researches of one-step electrolytic hydrogenation of TL have just been started[1]. DSA® type anodes composed of IrO2-based electrocatalyst coated on Ti which have excellent activity and extremely high durability for oxygen evolution reaction (OER)[2] is required as a counter electrode of electrolytic process. It is well known that some organic additive lead serious degradation of the anodes[3]. IrO2-Ta2O5/Ti would be a good candidate, because the overpotential of IrO2-Ta2O5/Ti in sulfuric acid with organic compound contamination is lower than that of IrO2/Ti [3]. However, the OER activity of IrO2-Ta2O5/Ti would not still be enough and the effect of TL and MCH on the activity and durability have not been clarified. In this study, activity of IrO2-Ta2O5 based Ti electrodes whose Ta is replaced by Zr was investigated in sulfuric acid with TL contamination. Experimental The precursor of the electrocatalyst was n-butanol solution of H2IrCl6・6H2O, Ta(C4H9O)5 and Zr(C4H9O)4 with nominal composition of Ir: Ta: Zr= 50: (50-X): X (0 ≦X < 50) in mole fraction. A pretreated Ti plate was dipped in the precursor, and dried at 100 oC for 10 min. Then it was thermally decomposed at 500 oC for 10 min. The process of the dipping, drying, and decomposition were repeated several times to get around 10 g m-2 of IrO2 loading. Finally, it was baked at 500 oC for 1h. The loading was evaluated by a X-ray fluorescent analysis. Polarization of the OER was evaluated with 5 mV s-1 of potential sweep between 1.2 and 2.0 V vs. RHE in 1 M H2SO4 with and without saturated TL at 60oC. A counter electrode and a reference electrode were platinum wire and reversible hydrogen electrode, respectively. Resistance of the electrolyte and double layer capacitance was evaluated with AC impedance method. Results and discussion Double layer capacitance (C dl) of IrO2/Ti, Ir50Ta50-Oxide/Ti and Ir50Ta20Zr30-Oxide/Ti anodes in 1 M H2SO4 at 60 oC were 2.1, 25, and 75 mF cm-2, respectively. The C dl of the Ir50Ta20Zr30-Oxide/Ti was three times larger than that of Ir50Ta50-Oxide/Ti which was ten times larger than the IrO2/Ti. The C dl corresponds to the real surface area for precious metal oxide coated electrode [4]. Therefore, Ta and Zr additives increase the real surface area of the IrO2 based coating, and the ternary system would increase real surface area compared to the binary system. The polarization curves for OER current density on IrO2/Ti, Ir50Ta50-Oxide/Ti and Ir50Ta20Zr30-Oxide/Ti in 1 M H2SO4 with and without saturated TL were shown in Fig. 1. The current densities in Tafel region were 0.9, 13, and 115 mA cm-2 at 1.55 V vs. RHE in 1 M H2SO4 at 60 oC for IrO2/Ti, Ir50Ta50-Oxide/Ti and Ir50Ta20Zr30-Oxide/Ti, respectively. The large potential reduction more than 100mV at 100 mA cm-2 was obtained with Ir50Ta20Zr30-Oxide/Ti compared to the others, reflecting their C dl values. While the current density of IrO2/Ti decreased by 43% with TL contamination, the others decreased by 10% or less with TL contamination. The current densities based on C dl on Ir50Ta(50-X)Zr X -Oxide/Ti at 1.55 V vs. RHE in 1 M H2SO4 with and without saturated TL were shown in Fig. 2. They increased with Zr content, and the decrement of current density by TL contamination was kept constant in spite of change in Zr content. TL would decrease the current density of OER with the adsorption onto IrO2. However, the addition of Ta might prevent the adsorption of TL onto IrO2 due to the catalytic contribution on Ir and the addition of Zr might mainly increase the real surface area without changing the Ta effect. Acknowledgments This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), “energy carrier” (Funding agency: JST). We applicate the person concerned them. References S. Mitsushima, Y. Takakuwa, K. Nagai, Y. Kohno, K. Matsuzawa, Proceedings of the Grand Renewable Energy 2014, O-Hf-5-1(2014).J. Krysa, L. Kule, R. Mraz, I. Rousar, J. Appl. Electrochem, 26, 999(1996).M. Takahashi, Soda to Enso, 12, 531(1988).L.A. da Silva, V.A. Alves, M.A.P. da Silva, S. Trasatti and J.F.C. Boodtst, Electrochem. Acta, 42, 272 (1997). Figure 1

Fabrication of strongly attached hydroxyapatite coating on titanium by hydrothermal treatment of Ti-Zn-PO4 coated titanium in CaCl 2 solution.

Hydroxyapatite (HAp) coating was formed on zinc phosphate (Ti-Zn-PO4) coated Ti plates by hydrothermal treatment in CaCl2 solution at 200°C for 12h. Uniform surface coverage of the fabricated HAp coating was obtained by this method. SEM-EDX analysis of the adhesion test area showed that the presence of fractures only occurred in HAp crystals. On the other words cohesive fracture was seen in HAp coating layer formed on the Ti-Zn-PO4. The measured strength was around 42.3±17MPa. Rat bone marrow (RBM) mesenchymal stem cells were cultured and differentiation-induced on each sample (Ti plate, Ti-Zn-PO4 coated and HAp coated), and cell calcification properties were examined. Apparent differences in morphology and extension of the RBM cells were obtained, while the Ti-Zn-PO4 coated samples showed the highest cell number among all samples. After differentiation-induction, HAp coated samples showed the highest amount of alkaline phosphatase activity, and the highest level of cell calcification. Therefore, the hard tissue compatibility of Ti is improved by hydrothermally HAp coating of samples.

Microstructural evolution and mechanical properties of laser melting deposited Ti–6.5Al–3.5Mo–1.5Zr–0.3Si titanium alloy

A rectangular plate of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si titanium alloy was fabricated by laser melting deposition (LMD) technology. Macrostructure and microstructure were characterized by optical microscope (OM) and scanning electron microscope (SEM). Room temperature tensile properties were evaluated. Results indicate that the macro-morphology is dominated by large columnar grains traversing multiple deposited layers. Two kinds of bands, named the wide bands and the narrow bands, are observed. The wide band consists of crab-like α lath and Widmanstätten α colony. The narrow band consists of α lath and transformed β. The formation mechanism of the two bands was explored. The influence of heat effect caused by subsequent deposition layers on microstructural evolution during deposition process was discussed. The room temperature tensile test demonstrates that the strength of laser deposited Ti–6.5Al–3.5Mo–1.5Zr–0.3Si is comparable to that of wrought bars.

Crystal Structure And Optical Properties Of TiO2 Thin Films Prepared By Reactive RF Magnetron Sputtering

Abstract In sputtering deposition process of TiO2, metal Ti or sintered TiO2 target is used as deposition source. In this study, we have compared the characteristic of target materials. When TiO2 target was used, stoichiometric TiO2 films was deposited under the Ar atmosphere containing 1.0% of oxygen. The highest sputtering rate under this atmosphere was 3.9nm/min at 3.4W/cm2. But, sintered TiO2 target is fragile and cannot endure higher density of input power than 3.4W/cm2. On the other hand, Ti target needs higher oxygen concentration (8%) in sputtering gas atmosphere for obtaining rutile/anatase. Even though Ti target can be input twice power density of 7.9W/cm2, the highest deposition rate for Ti target was 1.4/nm, which was ~35% of the highest rate for TiO2 target. Then we have study out the composite target consisting of Ti plate and TiO2 chips. Using the composite target, stoichiometric TiO2 films were prepared in the rate of 9.6nm/min at 6.8 W/cm2 under the atmosphere of Ar/2.5%O2. Furthermore, we have found that the TiO2 films obtained from the composite target consisted of about 100% anatase, whereas TiO2 films obtained from other target have rutile dominant structure. The optical band gap energy of the film is determined by using the Tauc plot. The calculated band gap energies for the films deposited by Ti target and composite target were 2.95 and 3.24eV, which are equivalent to that of rutile and anatase structure, respectively.

Photoelectrochemical Phenomena at Nano-V2O5 Films Impregnated with Bi3+

In the last two decades, the development of nanoscience and technology developed several nanostructures at different forms, such as nanoparticles, nanowires, nanotubes and nanoribbons. These materials offer a high potential for improving properties and can be used in many fields such as microelectronics, batteries, photovoltaic and photocatalytic devices. Vanadium oxides belong to the important class of 3d transition metals, with various electric, magnetic and structural properties, making these materials attractive for many industrial applications. This study aimed to obtain and characterize vanadium oxide films on titanium from ammonium metavanadate and then modify it by impregnation with Bi (III). The vanadium pentoxide was synthesized on Ti substrates by painting the surface with a suspension of 250 mg ammonium metavanadate in 5 ml of polyethylene glycol (PEG-300). The coated Ti plate was then heated at 400, 500 or 600 °C for one hour. Subsequently, the film obtained was impregnated with Bi (III) for 120 minutes under constant stirring, using 50 mL of a solution 10 mmol L-1 of bismuth nitrate at nitric acid. Then the samples were again annealed for one hour at the same temperature. The films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV-Visible spectroscopy and photoelectrochemical. From SEM analysis was possible to observe, after impregnation of Bi(III), the growing of long crystals on V2O5 films at 400 and 500 °C, while for the sample to 600 °C a globular structure was preferentially deposited on the tip of V2O5 crystals. Through EDS analysis it was observed that the sample obtained at 500 °C is that has the highest amount of Bi in the composition. The mapping by EDS showed that the elements were distributed over all surface. From XRD analysis the presence of V2O5 orthorhombic phase and monoclinic BiVO4 was detected. Band-gap calculated for the samples before and after impregnation also proved that V2O5 was converted to BiVO4, since the value before impregnation was 2.20 eV and after impregnation showed a value of 2.42 eV. The photocurrent value obtained for nano-V2O5 films impregnated with Bi3+ at 500 °C was 5 times higher than pure BiVO4 films. The results showed that it has been possible obtain a nanostructured V2O5 / BiVO4film on Ti substrate which is photoactive and could be used both in photoelectrocatalytic water as oxidation of organic molecules. Acknowledgements: FAPESP 2012/23422-5 and CAPES.

One-step hydrothermal synthesis of C-N-S-tridoped TiO2-based nanosheets photoelectrode for enhanced photoelectrocatalytic performance and mechanism

C-N-S-tridoped TiO2-based nanosheets(BNSs) photoelectrode was prepared via a one-step hydrothermal strategy of the Ti plate in mixed solution of NaOH and cystine, followed by acid-washing and calcination. The resulting samples were characterized by X-ray photoelectron spectroscopy (XPS), scanning electrons microscopy (SEM), X-ray diffraction (XRD) and UV-vis diffuse reflectance spectra (DRS). XPS analysis indicated that C, N and S were transferred into the lattice of TiO2. Highly ordered TiO2-BNSs with the sheet lengths of 500–1500nm and thickness of about 30nm were observed. XRD patterns showed that TiO2-BNSs before and after C, N and S tridoping were biphase of anatase-rutile. And tridoping with C, N and S could promote the phase transition from anatase to rutile and restrain growth of rutile crystallites. In addition, a shift of the absorption edge towards low energy and the intense visible light absorption were achieved. Photoelectrochemical (PECH) properties of the C-N-S-tridoped TiO2-BNSs photoanode were investigated through transient photocurrent response (TPR), open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). The photoelectrocatalytic(PEC) performances were evaluated by the yield of •OH radicals and degradation of methyl orange(MO) under Xenon lamp irradiation. The results showed that C-N-S-tridoped TiO2-BNSs photoelectrode revealed high photogenerated current of 0.69mAcm−2, open-circuit photovoltage of -0.66mVcm−2, generation of •OH radicals and PEC efficiency of 96.8% for the degrading MO. Moreover, the enhanced PEC mechanism was proposed. The high PEC performance could be ascribed to the tridoping with C, N and S, which could not only improve the light harvesting in visible region but also enhance the mobility and separation efficiency of photogenerated charge carriers.

Porous cobalt phosphide nanorod bundle arrays as hydrogen-evolving cathodes for electrochemical water splitting

Abstract An advanced electrode composed of porous CoP nanorod bundle arrays (NBAs) on Ti plate was fabricated by using Co 3 O 4 NBAs as precursors and developed as a robust self-supported hydrogen-evolving cathode for electrochemical water splitting. Such electrode exhibited remarkable activity for hydrogen evolution reaction in a wide pH range, affording a low onset overpotential, small Tafel slope, and long-term stability.

Effects of CaCl2 hydrothermal treatment of titanium implant surfaces on early epithelial sealing

Improvement of oral epithelial adhesion to titanium (Ti) may significantly enhance the efficacy of dental implants. We aimed to investigate whether calcium chloride (CaCl2) hydrothermally treated (HT) Ti could promote sealing of the peri-implant epithelium (PIE) around the implant. Right maxillary first molars were extracted from rats and replaced with either CaCl2-HT implants (Ca-HT group), distilled water-HT implants (DW-HT group), or untreated implants (Cont group). After 4 weeks, the implant–PIE interface of the Ca-HT group exhibited a band of immunoreactive laminin-332, similar to the tooth–junctional epithelium interface, which was absent in the Cont and DW-HT groups at the upper portion. We also investigated the effect of Ca-HT on the attachment of rat oral epithelial cells (OECs). OEC adherence onto Ca-HT Ti plates was stronger with higher expression levels of adhesion proteins compared with Cont and DW-HT groups. These results indicate that HT with CaCl2 improves the integration of soft tissue cells with the Ti implant at 4 weeks after implantation, which might facilitate the development of a soft tissue barrier around the implant.

Electrochemical oxidation of ammonia-containing wastewater using Ti/RuO2-Pt electrode

The electrochemical oxidation degradation processes for artificial and actual wastewater containing ammonia were carried out with a Ti/RuO2-Pt anode and a Ti plate cathode. We studied the effects of different current densities, space sizes between the two electrodes, and amounts of added NaCl on ammonia-containing wastewater treatment. It was shown that, after a 30-min treatment under the optimal conditions, which were a current density of 20 mA/cm2, a space size between the two electrodes of 1 cm, and an added amount of 0.5 g/L of NaCl, the COD concentration in municipal wastewater was 40 mg/L, a removal rate of 90%; and the NH3-N concentration was 7 mg/L, a removal rate of 88.3%. The effluent of municipal wastewater qualified for Class A of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).

Efficient and selective electro-reduction of nitrobenzene by the nano-structured Cu catalyst prepared by an electrodeposited method via tuning applied voltage

Pollution caused by toxic nitrobenzene has been a widespread environmental concern. Selective reduction of nitrobenzene to aniline is beneficial to further efficient and cost-effective biologic treatment. Electrochemical reduction is a promising method and Cu-based catalysts have been found to be an efficient cathode material for this purpose. In this work, Cu catalysts with different morphologies were fabricated on Ti plate using a facile electrodepositon method via tuning the applied voltage. The dendritic nano-structured Cu catalysts obtained at high applied voltages exhibited an excellent efficiency and selectivity toward the reduction of nitrobenzene to aniline. Effects of the working potential and initial nitrobenzene concentration on the selective reduction of nitrobenzene to aniline using the Cu/Ti electrode were investigated. A high rate constant of 0.0251 min–1 and 97.1% aniline selectivity were achieved. The fabricated nano-structured Cu catalysts also exhibited good stability. This work provides a facile way to prepare highly efficient, cost-effective, and stable nano-structured electrocatalysts for pollutant reduction.

Molybdenum sulfide nanosheet arrays supported on Ti plate: an efficient hydrogen-evolving cathode over the whole pH range

Electrochemical water splitting offers a simple route to make hydrogen and it is of great importance but still remains a big challenge to develop cost-effective electrocatalysts for catalyzing the hydrogen evolution reaction over the whole pH range. In this work, molybdenum sulfide nanosheet arrays are hydrothermally grown on Ti plate as an integrated 3D hydrogen-evolving cathode. This electrode exhibits high catalytic activity in acidic media, displaying 10 and 100mAcm−2 at overpotentials of 108 and 205mV, respectively, and it operates stably within 55h of operation. Moreover, this electrode is also capable of efficiently catalyzing the HER under neutral and strongly basic conditions.

Formation of periodic nanostructures using a femtosecond laser to control cell spreading on titanium

Although titanium (Ti) is a common biomaterial, controlling cell spreading by forming periodic structures using a femtosecond laser should improve its biocompatibility. Herein we investigate the influence of periodic nanostructures formed on the surface of a Ti plate on cell spreading. Nanostructures with a periodicity of 590 nm are formed using a femtosecond laser with a wavelength of 775 nm. Cell spreading on the plate without period structures lacks a definite direction, whereas cell spreading on the Ti plate with periodic structures occurs along the grooves, suggesting that forming periodic structures via a femtosecond laser can control cell spreading.

Ferric phosphide nanoparticles film supported on titanium plate: A high-performance hydrogen evolution cathode in both acidic and neutral solutions

In this paper, we demonstrate the preparation of ferric phosphide nanoparticles film supported on titanium plate (FeP/Ti) through low-temperature phosphidation of electrodeposited ferric hydroxide nanoparticles film on Ti plate. When directly used as a hydrogen evolution cathode in acidic media, the FeP/Ti shows high catalytic performance and durability with nearly 100% Faradaic efficiency. It needs overpotentials of 116 and 191 mV to afford current densities of 10 and 100 mA cm−2, respectively, and the catalytic activity is maintained for at least 12 h at an overpotential of 150 mV. This electrode also performs well in neutral solutions.

Surface morphology of Ti–6Al–4V plate fabricated by vacuum selective laser melting

A plate made of Ti–6Al–4V (Ti64) was built by vacuum selective laser melting (SLM) at a pressure of 10−2 Pa. The vacuum SLM system employed a single-mode fiber laser and three-axis galvanic mirror in order to form 3D metallic structure. In order to investigate the surface morphology on the fabricated plates, Vickers microhardness and surface roughness R a were measured. From the results, the Vickers microhardness of the fabricated plates was recorded at 391 HV, higher than the typical 340 HV for a Ti64 plate. It was also determined that crystal orientation was evaluated with X-ray diffraction. From the results, the crystal orientation of powder is composed mainly of martensitic alpha. Diffraction peaks corresponding to β (110) were detected in vacuum SLM processed samples.