Ecm Titanium 1.73 326
Abdul Soumphonphakdy
Titanium dioxide (TiO2) is one of the most widely studied transition metal oxide semiconductors due to its nontoxic nature, chemical stability, and commercial availability at a low cost, robust, and general reactivity. During the past decades, TiO2 thin films have attracted much interest because it has a wide range of promising energy and environmental applications, such as hydrogen generation by water splitting [1], photocatalytic water purification [2], dye-sensitized solar cells [3], and gas sensors [4]. Recently, few people have fabricated amorphous nonstoichiometric titanium dioxide, (a-, where is smaller than 2) thin films by different methods and pointed out that a- thin films are potential thermal sensing material for an uncooled IR bolometer imager [5]. However, the effect of the deposition process on the film structure, composition and electrical properties of this material such as resistivity, temperature coefficient of resistivity (TCR), and activation energy, have not been illustrated up to now, and these factors are very crucial for the detectivity of thermal IR detectors.
Figure 3 shows a typical experimental RBS spectrum of titanium oxide films (S25) deposited on p-silicon (100) substrate with the simulated spectrum using the program SIMNRA [16]. The O/Ti stoichiometry across the films have been obtained by simulating the experimental spectrum (circle) and theoretical spectrum (line). The results presented in Table 1 show the O/Ti ratio is in accordance with the pO2, and all the films have nonstoichiometry compositions.
At present, the oxygen-rich TiO2 is mainly prepared by the thermal decomposition of peroxo-titania complex xerogel, in which the H2O2 solution is usually used as the oxygen rich chemicals8,9. We all know that the H2O2 solution easily react with titanium tetrachloride (liquid)11, titanium sulfate12, titanium alkoxides (liquid)9,13 or amorphous H2TiO3 powder (hydrous TiO2nH2O)14,15,16, to generate the soluble peroxo titanate complex under the room temperature. However, the crystalline TiO2 is simply treated by H2O2 to not produce the peroxide TiO2 crystal or the soluble peroxide titanate complex, and to form the Ti-O-O coordination bonds in the face of TiO2 crystal17,18. This is due to the solid structure of TiO2 crystal, resulting in that the H2O2 molecules cannot enter into the inward of TiO2 crystal.
It is well known that Ti(IV) easily occurs coordination reaction with hydrogen peroxide H2O2 to form Ti-hydroperoxide species with yellow25. In fact, TiO2 crystals is simply placed into the H2O2 solution, we cannot observe the color change of TiO2 crystals with the unaided eye. However, it is interesting that the color of layered titanium oxide HTO crystal quickly changes into yellow from white when it meet with H2O2 solution (Fig. 1a,b), and the H2O2 solution remains colorless and transparent. The FE-SEM images display that the H2O2 treated HTO crystal still possesses the platelike shape with smooth surface (Fig. 1c,d). These indicate that the HTO crystal cannot corrode or dissolve in the H2O2 solution, and its platelike morphology and microstructural are not influenced by H2O2. The phenomenon of the HTO color change should be due to the formation of the Ti-O-O coordination bonds.
On the basis of the above results, we propose a formation mechanism of the peroxide layered titanium oxide HTO crystal from the layered titanium oxide HTO crystal, as shown in Fig. 5. The mechanism of formation of the peroxide HTO crystal consists of the displacement reaction and in situ coordination reaction. When the HTO crystal comes in contact with the H2O2 molecules, the H2O2 molecules easily intercalate with TiO6 interlayer via H2O2/H2O exchange, resulting in the increase of TiO6 layers spacing (Fig. 4). At the same time, due to the strong Ti(IV) coordination ability of H2O2, the H2O2 molecules straightaway in situ coordinate with Ti within TiO6 octahedron in the interlayers (Fig. 3). Although we cannot accurately decide which coordination type (type I, type II in Fig. 5 or others) in the interlayers, it is affirmed that the peroxide layered titanium oxide HTO crystal with containing Ti-O-O coordination bonds in TiO6 interlayers is formed. The mechanism described above suggests that the titanium oxide crystal with open structure can be used as precursor for the preparation of the peroxide titanate.
How to cite this article: Kong, X. et al. Ti-O-O coordination bond caused visible light photocatalytic property of layered titanium oxide. Sci. Rep. 6, 29049; doi: 10.1038/srep29049 (2016).
Our titanium version of the Chimera is hand-assembled in Los Angeles with a lightweight all-titanium frameset, powerful 3800 watt High-Drive powertrain, Magura MT series brakes/Storm HC rotors, Kenda Tires, ASI controller, Sun/Ringle rims, and our custom high current potted and aluminum encased battery. The final weight estimate is 39lbs all-in before any weight-saving customizations. See "specs" tab below for more details.
Our titanium bikes are pre-order only. Please understand that when you make a pre-order, your bike will be put into production, and will take up to 7 months to deliver to you (depending on our order volume). Once your bike is in production, it can only be cancelled for a refund minus a $300 fee to help partially recover our costs of raw materials and labor. For more information, see our refund and warranty polices. For legal reasons, we have to say that the top speed is 15mph.
K0.8Ti1.73Li0.27O4 (KLTO) is an important titanium-based anode material for lithium-ion batteries (LIBs) and is expected to become an alternative to carbonaceous materials on account of its nontoxicity, low cost, and high safety performance. However, it suffers from poor specific capacity at high charge-discharge rates due to its low conductivity and obstructed Li-ion diffusion. In this work, an Fe-doped KLTO@rGO (Fe-KLTO@rGO) composite prepared by following a simple electrostatic assembly process and its high-rate and long-cycle-life-performance as an anode in LIBs is obtained. The Fe-KLTO@rGO composite sample has an excellent specific capacity of 330 and 105 mAh g-1 at a current density of 1 C (1 C = 175 mA g-1) and 50 C, respectively. In addition, the Fe-KLTO@rGO composite sample can carry out a long cycle of 3000 cycles at a rate of 50 C, and the specific capacity remains at 127 mAh g-1.
The golf industry has made significant (and I mean significant) improvements in driver technology in recent decades. I started playing golf with a wood driver and quickly found my way into the metal wood family, which was replaced by titanium shortly afterward. I hardly stopped to think about buying the newest technology, but it always seemed to help.
The layered titanium oxide is a useful and unique precursor for the facile and rapid preparation of the peroxide layered titanium oxide H1.07Ti1.73O4nH2O (HTO) crystal with enhanced visible light photoactivity. The H2O2 molecules as peroxide chemicals rapidly enter into the interlayers of HTO crystal, and coordinate with Ti within TiO6 octahedron to form a mass of Ti-O-O coordination bond in the interlayers. The introduction of these Ti-O-O coordination bonds result in lowering the band gap of HTO, and promoting the separation efficiency of the photo induced electron-hole pairs. Meanwhile, the photocatalytic investigation indicates that such peroxide HTO crystal has the enhanced photocatalytic performance for RhB degradation and water splitting to generate oxygen under visible light irradiating.
Figure 7 shows the contact angle measurements of each sample surface with distilled water and ethylene glycol, as well as the forms of distilled water droplets on different sample surfaces; the black portions underneath the water droplets are the samples. Regardless of whether the tested liquid was distilled water or ethylene glycol, after MAO processing, the contact angles of the coating surface all decreased in comparison with the ultrafine-grained pure titanium substrate, and hydrophilic performance improved significantly. In particular, when the oxidation time was 9 min, the contact angles decreased from 63.1 and 43 to 13.2 and 17, respectively, because the rough and porous surface structure possessed increased water retention capacity after MAO.
As demonstrated in Figure 7, the droplets on the substrate surfaces were nearly hemispherical. After MAO processing, the droplets were more able to spread over the ultrafine-grained pure-titanium MAO coating surface. This indicated that MAO processing reduced the contact angles of the sample surfaces and could more favorably enhanced their wettability.
According to the determined test liquids (distilled water and ethylene glycol) in ultrafine-grained pure titanium and the contact angles of the MAO coating surface at different oxidation times, as well as the surface energy parameters (as Table 1) of these test liquids, the Owens two-liquid method was used to calculate the surface energy of the samples:
In comparison to the substrate, the MAO coating surface possessed more favorable performance in preventing platelet adhesion and deformation. This was primarily because the adhesion of platelets on a material surface is closely related to the types, numbers, and 3D conformation changes of the plasma proteins adsorbed by the material surface, primarily albumin and fibrinogen. When the protein layer adsorbed by the surface of the material was albumin, the material surface demonstrated biopassivation, reducing the adhesion of platelets on the surface and preventing coagulation [32], as shown in Figure 13a. Sawyer et al. [33] proposed an electrochemical hypothesis, finding that the electronic structure of fibrinogen was similar to that of intrinsic semiconductors. The forbidden band gap was narrow, measuring 1.8 eV. After fibrinogen was adsorbed on the material surface, its valence electrons were transferred to the material surface it was in contact with. This caused the conformational change of the fibrinogen and decompose the fibrinogen into fibrin monomers and fibrinopeptides, followed by polymerization and cross-linking between monomers to form an intermediate polymer, accelerating the coagulation process. Thus, to prevent the transfer of the electric charge direction and the material it was in contact with, the material must possess a smaller work function [34]. After the ultrafine-grained pure titanium substrate underwent MAO modification, it formed a porous ceramic coating with the mixed crystal structures of anatase- and rutile-phase TiO2 as its primary body. As shown in Figure 13b, TiO2 possessed the characteristics of wide forbidden-band-gap semiconductors, with a gap of 3.2 eV. The conduction and forbidden bands of fibrinogen were located in the forbidden band gap of TiO2, and electrons were in the conduction band of TiO2. This inhibited the transfer of electrons from the TiO2 coating surface by the adsorbed fibrinogen and was beneficial in maintaining the normal fibrinogen conformation; it was, thus, more difficult for platelets to aggregate on the TiO2 coating surface and deform.
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