Effect of Hydrogen on the Formation of Porous TiO[sub 2] in Alkaline Solution

Tanaka, Shin‐ichi; Iwatani, Takuji; Hirose, Norimitsu; Tanaki, Toshiyuki

doi:10.1149/1.1518989

Cited by 30 publications

(44 citation statements)

References 18 publications

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“…Especially, the absorbed hydrogen and/or the hydride in the titanium plays an important role in the formation of porous layer. 13,14 However, although the titanium does not absorb the hydrogen before immersion in this research, the porous structure is obtained only when the titanium immersed in 5 M NaOH at 353 K for 24 h, as shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 72%

Effect of the Temperature and Concentration of NaOH on the Formation of Porous TiO[sub 2]

Tanaka

Hirose

Tanaki

2005

J. Electrochem. Soc.

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The influence of the temperature and concentration of NaOH on the formation of porous TiO 2 was investigated. The porous TiO 2 was obtained only after a 24-h immersion in 5 M NaOH at 353 K. The X-ray diffraction pattern indicated that the porous layer consisted of a mixture of anatase and rutile types of TiO 2 . During immersion in the NaOH solution, the anodic and cathodic reactions proceed at the same time on the titanium. From the cathodic polarization measurements, the cathodic reaction proceeded mainly the hydrogen evolution reaction. Therefore, a part of the adsorbed hydrogen penetrated into the titanium. The penetration of hydrogen confirmed with a glow discharge optical emission spectroscopy. The hydrogen evolution reaction continues during immersion in the 5 M NaOH solution at 353 K. However, the hydrogen evolution did not proceed in the low concentration of NaOH solution or at below 283 K. In addition, although the hydrogen evolution continues during immersion in 5 M NaOH solution at 303 or 333 K. As a result, the content of hydrogen in the titanium is insufficient to form the porous TiO 2 layer so that the porous layer is not produced on the titanium. Titanium dioxide ͑TiO 2 ͒ has favorable optical properties and a good stability in corrosive environments. Since O'Regan and Grätzel 1 reported the high-efficiency solar cell based on dyesensitized porous TiO 2 films in 1991, porous TiO 2 has become one of the most interesting materials in the field of solar cells and photoelectrochemistry. Since then, many researchers have vigorously investigated the formation of porous TiO 2 in order to use it as a material to convert photoenergy into electric energy. 2-6 Porous TiO 2 is also an attractive material in the field of biomaterials. This is because the porous TiO 2 can enhance the adhesion between an artificial bone, which is based on a titanium alloy, and calcium phosphate. [7][8][9][10] Although these properties, such as energy conversion efficiency and adhesion resistance, may be influenced by the structure of the porous TiO 2 , such as porosity, film thickness, and so on, the factor controlling these parameters has not been defined in detail. This is because the mechanism of the preparation for porous TiO 2 in alkaline solution has not yet been clarified. Generally, the porous TiO 2 was prepared by immersing in alkaline solution at high temperature for several hours. 8-12 However, we reported that the formation of porous TiO 2 was strongly dependent on the initial surface conditions of the titanium and the porous layer was only obtained in the presence of TiH 2 or a hydrogen-absorbed layer in the titanium before immersion in NaOH solution. 13,14 Therefore, we have proposed that the surface condition of titanium before immersion is an important factor for the formation of porous TiO 2 .In this study, we prepared the porous TiO 2 on the surface of titanium by immersing it in an alkaline solution in order to investigate the influence of the solution temperature and the concentration of NaOH on the formation...

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Section: Resultsmentioning

confidence: 72%

Effect of the Temperature and Concentration of NaOH on the Formation of Porous TiO[sub 2]

Tanaka

Hirose

Tanaki

2005

J. Electrochem. Soc.

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“…4(b)). The porosity structure was obtained after prolonged immersion in an alkaline solution [12,13]. In previous studies, the effects of nano-(␥-TiH and ␦-TiH 0.71 ) phases on the formation of nanoporous titanium oxide by chemical treatment had been explored.…”

Section: Resultsmentioning

confidence: 99%

“…In this manner, the corrosion resistance of titanium-based alloys can be improved by thickening the oxide film. Ti films pretreated in H 2 O 2 have exhibited enhanced oxide growth and increased in the adsorption of plasma proteins [12,13]. The thickness of the oxide layer increased with time, and ions from the physiological environment become incorporated into the growing oxide [2,[8][9][10]26].…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, a nanoporous and thick titanium oxide surface can induce bony ingrowth into the porous structure, resulting in morphological fixation of the implants to the bone [8][9][10]. Previously, numerous procedures for forming titanium oxide films have been examined [8][9][10][11][12][13][14]. Among them, anodization is very popular.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, micro-arc oxidation often leads to high-voltage-induced surface damages, including microcracks [17]. The effects of hydrogen charging on the formation of porous TiO 2 on Ti in alkaline solutions have been examined by many researchers [12,13]. But does not include information concerning the microstructural identification and phase transformation of titanium hydride.…”

Section: Introductionmentioning

confidence: 99%

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