WO2006087841A1 - Nanotube d’oxyde de titane et procédé de fabrication idoine - Google Patents

Nanotube d’oxyde de titane et procédé de fabrication idoine Download PDF

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WO2006087841A1
WO2006087841A1 PCT/JP2005/017013 JP2005017013W WO2006087841A1 WO 2006087841 A1 WO2006087841 A1 WO 2006087841A1 JP 2005017013 W JP2005017013 W JP 2005017013W WO 2006087841 A1 WO2006087841 A1 WO 2006087841A1
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titanium oxide
titanium
nanotube
metal
doped
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PCT/JP2005/017013
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English (en)
Japanese (ja)
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Koichi Niihara
Tohru Sekino
Takumi Okamoto
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Osaka University
Kansai Technology Licensing Organization Co., Ltd.
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Priority to JP2007503572A priority Critical patent/JP4868366B2/ja
Publication of WO2006087841A1 publication Critical patent/WO2006087841A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B01J35/39—
    • B01J35/58—
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C01P2004/13—Nanotubes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/542—Dye sensitized solar cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • Titanium oxide nanotube and method for producing the same
  • the present invention relates to a titanium oxide nanotube having conductivity and improved heat resistance, and a method for producing the same.
  • Titanium oxide represented by the general formula TiO has excellent photocatalytic performance
  • nanotubes with a diameter of about 10 nm or less can be formed by using a low-temperature chemistry process that is used in various fields such as super-water-repellent coatings. (Patent Documents 1 and 2 etc.).
  • TiO NTs Such titanium oxide nanotubes (hereinafter also referred to as "TiO NTs")
  • Patent Documents 3 and 4 etc. dye-sensitized solar cell electrodes
  • Patent Document 5 fuel cell electrolyte using proton conduction
  • Patent Documents 6 catalyst
  • Patent Document 7 satisfying this requirement, a conductive oxide titanium nanotube containing a metal element in an internal space other than the crystal lattice of the titanium oxide nanotube is reported.
  • Power Thermal stability is required to maintain the high specific surface area specific to TiO NTs.
  • Patent Document 1 Japanese Patent Laid-Open No. 10-152323
  • Patent Document 2 JP 2002-241129 A
  • Patent Document 3 Japanese Patent Laid-Open No. 2004-146663
  • Patent Document 4 Japanese Patent Laid-Open No. 2003-332602
  • Patent Document 5 Japanese Patent Laid-Open No. 2003-282097
  • Patent Document 6 Japanese Patent Laid-Open No. 2003-236377
  • Patent Document 7 Japanese Patent Laid-Open No. 2003-261331
  • the present invention provides an acid-titanium nanotube having a low resistivity, appropriate conductivity, and improved heat resistance, and a method for producing the same. For the purpose.
  • the present inventor added a predetermined metal cation to titanium oxide powder and refluxed it in an alkaline aqueous solution. It has been found that metal cation-doped type oxide titanium nanotubes in which a part of Ti 4+ ) is substituted with the metal cation can be produced.
  • the oxide-titanium nanotube material has a reduced volume resistivity and moderate conductivity, and at the same time, the collapse temperature of the nanotube structure is greatly improved as compared with TiO NTs to which the metal cation is not added. Dramatically improved heat resistance
  • the present invention provides the following oxidized titanium titanium nanotubes and a method for producing the same.
  • Item 1 A titanium oxide nanotube doped with metal ions having an ionic radius of 0.035 to 0.15 nm.
  • Item 2 The titanium oxide nanotube according to Item 1, doped with metal ions having an ionic radius of 0.05 to 0.07 nm.
  • Item 3 Metal ion forces with ionic radii of 0.05 to 0.07 nm Mn 2+ (0. 067 nm), Mn 3+ (0.058 nm), Mn 4+ (0. 053 nm), Nb 4+ ( 0.068 nm), Nb 5+ (0. 064 nm), V 3+ (0. 064 nm), V 4+ (0. 058 nm), V 5+ (0. 054 nm), Cr 3+ (0. 062 nm), Co 2+ (0. 066 nm), Co 3+ (0. 0545 nm), Cu 3+ (0. 054 nm), Fe 3+ (0. 055 nm), Ge 4+ (0.
  • Item 4 The titanium oxide nanotube according to Item 2, wherein a metal ion having an ionic radius of 0.05 to 0.07 nm is doped by 0.005 to 5 mol% with respect to titanium ion (Ti 4+ ). Titanium oxide nanotubes.
  • Item 5 A method for producing a metal ion-doped oxytitanium nanotube comprising the following steps:
  • a metal compound containing a metal ion having an ionic radius of 0.035-0.15 nm is added to the titanium oxide powder with respect to the titanium ion (Ti 4+ ) of the titanium oxide powder.
  • Item 6 The method according to Item 5, wherein a metal compound containing a metal ion having an ionic radius of 0.05 to 0.07 nm is used.
  • Item 7 A dye-sensitized solar cell material comprising the titanium oxide nanotube according to any one of Items 1 to 4.
  • Item 8 A photocatalytic material having the power of an acid-titanium nanotube according to any one of Items 1 to 4.
  • Item 9 A chemical sensor material comprising the titanium oxide nanotube according to any one of Items 1 to 4.
  • the metal ion-doped type titanium oxide nanotube of the present invention is a tubular (tubular) body having an anatase type crystal structure as its basic structure, and an ion radius of 0.035-0. Characterized by the fact that metal ions of 15 nm are implanted (doped)
  • the doped metal ion functions as a carrier for generating a charge carrier, whereby electrical conductivity is improved, and the doped metal ion is Bonding is strengthened and thermal stability is improved by replacing part of the titanium ions in the crystal lattice without substitutional solid solution or interstitial solid solution in the crystal lattice.
  • the conductive acid-titanium nanotube described in Patent Document 7 is In addition, it is characterized by containing “aggregates of metal elements”, that is, the metal itself, in the space inside the titanium oxide nanotube.
  • the “metal element” indicates a metal having a valence of zero, that is, a “metal state”.
  • metal ion-doped type titanium oxide nanotubes of the present invention "metal ions (cations)" are added during the production process, and the valence is not zero. Has a positive charge.
  • the added metal ions (cations) exist in a solid solution state in the crystal lattice of titanium oxide with each ion isolated.
  • the metal ion-doped acid / titanium nanotube of the present invention is clearly different in structure from the conductive acid / titanium nanotube described in Patent Document 7.
  • the average diameter (outer diameter) of the cross section of the metal ion-doped oxide-titanium nanotube of the present invention is 5 to 20 nm, particularly 7 to 12 nm, and the inner diameter is 3 to 15 nm, particularly 4 to 8 nm. And its length is from lOOnm to: LOO ⁇ m, in particular from 300 nm to 5 ⁇ m.
  • the specific surface area by the BET method is 100 to 400 m 2 Zg, preferably 150 to 350 mVg.
  • the metal ions to be doped have an ionic radius of 0.035 to 0.15 nm, preferably 0.05 to 0.07 nm, and more preferably 0.055 to 0.065 nm.
  • ⁇ Mn 2+ (0. 0 67nm), Mn 3+ (0. 058nm), Mn 4+ (0. 053nm), Nb 4+ (0. 068nm), Nb 5+ (0. 064nm ), V 3+ (0. 064 nm), V 4+ (0. 058 nm), V 5+ (0. 054 nm), Cr 3+ (0. 062 nm), Co 2+ (0. 066 nm), Co 3 + (0. 0545nm), Cu 3+ (0.
  • Mn 3+ , Nb 5+ , V 5+ , Mo 5+ , W 6+ , Ni 2+ , Cr 3+ or Co 2+ are preferred, especially Mn 3+ , Nb 5+ , V 5+ or Cr 3+ is preferred.
  • the "ion radius” used in the present invention is a paper "Revised effective ionic radii and sy stematic studies of interatomic distances in halides and chalcogenides.”
  • RD Shann defined as “Ionic Radius” as defined in on, Acta Cryst. A32, 751-767 (1976).
  • the value described in the box as the radius of the metal ion described above is also a typical value defined in this paper.
  • the coordinating state (coordination number or geometrical arrangement) of an anion (a-ion) or a ligand that forms a pair with the metal ion (cation), or the metal Since it is a known fact in crystal chemistry that the ion radius slightly changes depending on the electron orbital state of the ion, the radius of the metal ion is not necessarily limited to the value described above.
  • Metal ions with strong ionic radii are close to the ionic radius (0.0605 nm) of titanium ions (Ti 4+ ) in titanium oxide nanotubes. Later, a stable bond is formed, and a strong nanotube crystal structure can be constructed. In addition, the metal ions can be intruded and dissolved in the voids in the crystal structure of the oxide titanium nanotube, thereby strengthening the crystal structure. Further, doping with metal ions having a valence different from that of titanium ions produces a carrier injection effect, and has an effect of improving the conductivity of the titanium oxide nanotube.
  • the metal ion is 0.01-5 mol%, preferably 0.1-1 with respect to the titanium ion. Contains Omol%.
  • 0.05 to 2 mol% is contained, and in the case where the metal ion is Mn 3+ , 0.05 to 5 mol% is contained, and the metal ion is contained. for nb 5+, 0. 01 ⁇ 1. containing Omol%, when the metal ion is V 5+, 0. containing 02 ⁇ lmol%, when the metal ion is C o 2+, 0. 02-1 Contains 5 mol%. If it is within the range, moderate conductivity and heat resistance are imparted to the nanotube.
  • the amount of metal ions contained in the product can be qualitatively and quantitatively analyzed by general chemical composition analysis. Specifically, the element is qualitatively and quantitatively analyzed non-destructively in a powder state using an X-ray fluorescence analyzer, or the product is dissolved in a strong acid solution, and this solution is inductively coupled plasma (ICP). )
  • the ratio of doped metal ions to titanium ions can be determined by a method for qualitative and quantitative analysis of elements using an emission spectroscopic analyzer. These quantitative In the analysis method, trace element analysis up to about several tens of ppm (0.001%) is possible.
  • the metal ion-doped type titanium oxide nanotube of the present invention has, for example, a general formula:
  • ⁇ represents a doped metal ion
  • X represents 0.0001 to 0.05
  • ⁇ represents an oxygen deficiency amount or an excess amount.
  • oxygen deficiency that is, vacancies
  • a metal ion ⁇ 2+ or ⁇ 3+
  • it has a higher valence than Ti 4+ and can generate oxygen-rich or cation deficient states by doping metal ions (M 5+ , M 6+ ).
  • metal ions M 5+ , M 6+
  • the valence of titanium in the metal ion-doped titanium oxide nanotube of the present invention is usually tetravalent, but not necessarily tetravalent, and the stoichiometric composition of oxygen is not limited to 2. Furthermore, doping with ions with a valence different from Ti 4+ generates electrons or holes as carriers, which can contribute to conductivity.
  • X is preferably 0.001 to 0.01.
  • ⁇ which is an oxygen deficiency amount or an excess amount
  • ⁇ is generally from about 0.025 to +0.05, particularly from -0.005 to +0.01.
  • Alkali metal ions Na +, ⁇ +, etc. used in the synthesis process, anions derived from acids used in neutralization treatment (cr, NO 2_ , SO 2_, etc.), or doping
  • the metal ion doped oxytitanium nanotube of the present invention includes conventional titanium oxide powder (volume resistivity: 3.9 ⁇ 10 5 ⁇ cm) and titanium oxide nanotube (volume resistivity: 3.4 X 10 Compared to 5 ⁇ cm), it has 1 to 2 digits lower volume resistivity (1 to 2 digits higher ⁇ electrical conductivity)! Specifically, the volume resistivity of the acid-titanium nanotube of the present invention is 1 ⁇ 10 5 to 1 ⁇ 1 0 3 ⁇ « ⁇ , especially 7 ⁇ 10 4 to 8 X 10 3 Q cm.
  • the volume resistivity of the resulting metal ion-doped oxide-titanium nanotube is as low as 1 X 10 4 to 8 X 10 3 ⁇ cm! Value.
  • the metal ion-doped acid oxytitanium nanotube of the present invention has a significantly higher decomposition (collapse) temperature of the tube structure than conventional titanium oxide nanotubes. Characteristic). Based on this thermal stability, when the titanium oxide nanotube is heated, the crystallinity of the nanotube increases while maintaining a high specific surface area and maintaining a one-dimensional nanotube structure. As a result, defects in the lattice and on the surface can be reduced, the number of trapped charges can be reduced, and charge transfer characteristics inside the nanotube can be further improved.
  • the metal ion-doped acid / titanium nanotube of the present invention forms an impurity order in the band structure of acid / titanium and forms a light absorption band in the visible light region. Visible light responsiveness is expressed. Therefore, a photocatalyst that can operate even with visible light is suitably used as a solar cell electrode.
  • the method for producing a metal ion-doped type titanium oxide nanotube of the present invention comprises: (1) adding a metal compound containing a metal ion having an ionic radius of 0.035-0.15 nm to a titanium oxide powder. Step of mixing titanium ions (Ti 4+ ) in the titanium powder with alkali so that the metal ions are in the range of 0. Ol to 5 mol%, and (2) Washing and neutralizing the obtained reaction product. After that, it becomes the process power to dry.
  • Titanium oxide powder as a raw material may have an anatase, rutile or brookite! /, Misaligned crystal structure, or a mixture thereof, or glass (amorphous). Quality) structure.
  • an alkoxide titanium metal such as titanium tetraisopropoxide may be used directly.
  • the particle size of the titanium oxide powder is preferably 10 to 500 nm, more preferably 50 to 300 nm, and particularly preferably 70 to 150 nm, from the viewpoint of causing an efficient chemical reaction with alkali described later.
  • the titanium oxide powder is made of, for example, titanium tetraisopropoxide (Ti (OPr)) or the like.
  • Hydrous titanium oxide obtained by hydrothermal decomposition of titanium ore with a strong acid such as nitric acid, calcining at 800-900 ° C (gas phase method), or tetrasalt ⁇ titanium (TiCl) with oxygen and Hydrogen
  • the metal compound added to the titanium oxide powder has an ionic radius of 0.035-0.15 nm (preferably ⁇ or 0.05 to 0.07 nm, more preferably 0.75 or 0.005 to 0.005). (065 nm) metal compounds including a metal compound.
  • metal compounds include Mn 3+ , Nb 5+ , Mo 5+ , W 6
  • Metal compounds containing ions such as + , Ni 2+ , V 5+ , C r 3+ , Co 2+ are preferred, especially Mn 3+ , Nb 5+ , V 5+ or C r 3+ ions Containing metal compounds are preferred.
  • metal oxides or metal halides examples include metal oxides or metal halides, nitrates, sulfates, alkoxides and the like containing metal ions having an ionic radius of 0.035 to 0.15 nm.
  • metal oxide examples include Cr 2 O 3, Mn 2 O 3, Nb 2 O 3, V 2 O, and CoO, and the metal halide
  • Examples include CrCl, MnCl, NbCl, VOC1, CoCl, etc.
  • Co (NO), Mn (NO), Cr (NO), etc. are exemplified, and sulfates include CoSO, Mn
  • Rogenides especially metal chlorides are preferred.
  • a metal compound having a metal ion radius of 0.035-0.15 nm is used in a range where the metal ion amount is 0.01 to 5 mol% with respect to titanium ions in the titanium oxide powder as a raw material.
  • the doping Cr 3+ is preferably in the range of 0.05 to 2 mol%, more preferably 0.1 to 0.5 mol%, with respect to the titanium ions of the raw titanium oxide powder.
  • Nb 5+ to be doped is 0 with respect to titanium ions of the titanium oxide powder.
  • V o is used as the metal compound, the doping of v 5+ with respect to the titanium ion of the titanium oxide powder is
  • CoO is used as the metal compound
  • the titanium oxide powder is mixed with a metal oxide having a metal ion radius of 0.035 to 0.15 nm and subjected to an alkali treatment. Specifically, the mixture is placed in an alkaline aqueous solution and refluxed.
  • alkaline aqueous solution include 1 to 20N, preferably 5 to 15N, more preferably 8 to 10N, aqueous sodium hydroxide or aqueous potassium hydroxide solution.
  • the reflux in the alkaline aqueous solution may be usually 105 to 120 ° C for 10 to 30 hours.
  • the metal ions are uniformly mixed with the titanium ions in the titanium oxide crystal to form a nanotube precursor.
  • the reaction product obtained by refluxing is washed and neutralized. Specifically, it is usually preferable to perform the treatment in the order of water washing, neutralization and water washing.
  • distilled water is preferably used. This is to remove excess alkali components used in the reaction.
  • washing with water (distilled water) and filtration are repeated until the liquidity of the solution containing the reactants becomes neutral (pH 6.8 to 7.6).
  • the water-washed product is treated with an acid such as hydrochloric acid. Usually, treatment with 0.05 to 0.5N hydrochloric acid is carried out until the liquidity of the reaction product becomes weakly acidic (pH 5.0 to 6.5).
  • the acid-treated product is washed with water.
  • distilled water can be used. In this process, washing with water (especially distilled water) and filtration are repeated until the liquidity of the solution containing the reactants becomes neutral (pH 6.8 to 7.6).
  • the reaction product washed with water and neutralized is separated from the solution and dried. Separation and drying may be performed by a centrifugal separation method, a suction filtration method, or lyophilization. If necessary, the separated reactants can be heat-dried at 40-60 ° C! / ⁇ .
  • the metal-ion-doped type titanium oxide nanotubes of the present invention are produced by force. When the metal ion-doped type titanium oxide nanotube is observed with SEM (Scanning Electron Microscope) or TEM (Transmission Electron Microscope), it has an outer diameter of 5 to 20 nm and a length of 100 ⁇ to 100 / ⁇ m. . The specific surface area by BET is 100 to 400 m 2 / g.
  • the manufacturing method of the present invention employs a low-temperature chemical process, can be self-assembled without a template to form metal ion-doped type titanium oxide nanotubes, and can be synthesized in large quantities at low cost. Therefore, it is extremely meaningful.
  • the metal ion doped type titanium oxide nanotube of the present invention has a high specific surface area, moderate electrical conductivity, and excellent thermal stability, and is a photocatalyst material (antifouling tile, filter for air purifier, etc. ), Chemical sensor materials (gas sensor materials, etc.), dye-sensitized solar cell materials, etc.
  • the nanotube of the present invention is used as a dye-sensitized solar cell material (electrode material, electron transport layer material, etc.), since it has excellent charge transfer characteristics, smooth electron transfer to the electrode from the dye cover is possible. It is preferable because it has thermal stability that can sufficiently withstand heat treatment during cell formation.
  • the titanium oxide nanotube of the present invention is coated on the conductive thin film of the glass with the conductive thin film to form a high specific surface area titer layer.
  • the nanotube of the present invention is used as a gas sensor (a gas sensitive film for a gas sensor or the like), a gas sensor having excellent responsiveness can be provided.
  • the gas sensor is a sensor that detects gases such as CO, CH, and NO, and includes an insulating film (base material) and a sensor.
  • the non-gas sensitive film is composed of a heater formed on the surface side.
  • the gas reacts with the gas-sensitive film activated by heating with the heater, causing a change in the resistance value of the gas-sensitive film.
  • By detecting the change in the resistance value of this gas sensitive film with the electrode Can be detected.
  • the cation-doped titanium oxide nanotube of the present invention is used as a gas sensor material, a dye-sensitized solar cell electrode material, or the like.
  • a gas sensor When used in a gas sensor, the responsiveness is improved, and when used as a dye-sensitized solar cell electrode, the charge transfer characteristics are improved.
  • the heat resistance is improved by the metal ion-added powder, heat treatment (sintering and baking) can be performed at a higher temperature, and as a result, the crystallinity of the nanotube can be increased while maintaining a high specific surface area.
  • the charge transfer characteristics can be further improved, and at the same time, the high dye and gas molecule adsorption amount derived from the high specific surface area is maintained! Speak.
  • a light absorption band can be formed in the visible light region, and photocatalytic performance and visible light as a solar cell electrode can be formed. Responsiveness can be expressed.
  • FIG.l shows a transmission electron microscope (TEM) photograph of Co 2 + -doped acid titanium nanotubes.
  • FIG. 2 is a diagram schematically showing a procedure for producing a thin film for measuring electrical resistivity.
  • FIG. 3 is a diagram showing the configuration of a thin film for measuring electrical resistivity.
  • FIG. 4 A graph showing the result of the thermal stability test, that is, the change in specific surface area with respect to the heat treatment temperature.
  • FIG. 5 shows scanning electron microscope (SEM) photographs at various temperatures of titanium oxide nanotubes doped with Mn.
  • FIG. 7 is a powder X-ray diffraction pattern of 0.5 mol% Mn-doped acid / titanium nanotubes and pure acid / titanium nanotubes.
  • FIG. 8 is a graph showing temporal changes in the amount of hydrogen generated from various titanium oxide samples.
  • Metal compounds (CrCl, Nb O, Mn O, CoO, V O) doped into titanium oxide powder (anatase type, purity 99.9%, particle size 300 nm, manufactured by High Purity Science Laboratory Co., Ltd.)
  • FIG. 1 shows a transmission electron microscope (TEM) photograph of an acid titanium nanotube doped with, for example, Co 2+ lmol% with respect to titanium ions.
  • the synthesized nanotubes had an outer diameter of 8 to 15 nm, a length of 100 nm to 5 ⁇ m, and a hollow nanotube structure.
  • the existence of substances other than the nanotube structure was not recognized, and it was found that only the portion of the hollow nanotube structure also had a force.
  • the electrical resistivity of the metal ion-doped type titanium oxide nanotube obtained in Example 1 was measured.
  • volume resistivity of this film was measured at room temperature by Van der Pauw method as in FIG. 3 (Toyo Tech two forces Co., R es it es t8308 type). Table 1 shows the measurement results. [0065] [Table 1] Measurement of volume resistivity (Van der Pauw Method) Sample Raw material Metal ion Volume resistivity
  • the various metal ion-doped type oxide titanium nanotubes have a volume resistivity higher than that of general equiaxed titanium oxide particles and pure titanium oxide nanotubes.
  • Example 1 Among the samples obtained in Example 1, Cr 3+ , Mn 3+ , Co 2+ , V 5+ , and Nb 5+ doped acid and titanium nanotubes and additive-free acid and titanium nanotubes were obtained. Then, a heat stability test was conducted.
  • the thermal stability test was performed by heating a sample between 200 ° C and 550 ° C for 1 hour in the air.
  • the temperature at which the specific surface area after heating is approximately 150 m 2 Zg is about 440 ° C for the additive-free titanium oxide nanotubes, whereas it is about 440 ° C for the Co 2+ and V 5+ doped nanotubes. It was estimated to be about 490 ° C, about 500 ° C for the Mn 3+ doped sample, about 530 ° C for the Nb 5+ doped sample, and about 550 ° C for the Cr 3+ doped titanium oxide nanotube.
  • the time point when the specific surface area was approximately 150 m 2 Zg was used as the judgment criterion for the following reason. It has been found from heating experiments and electron microscope observation that when the specific surface area of the nanotube (about 300 to 350 m 2 / g) is reduced by about half by heat treatment, the nanotube structure collapses and the hollow part inside disappears. The point when the specific surface area was about half (about 150m 2 Zg) was estimated as the limit value that could hold the structural characteristics of the nanotube, and this was used as the reference.
  • the metal ion doping increased the collapse temperature in the range of about 50 ° C to 110 ° C, and markedly improved thermal stability. Therefore, it goes without saying that it is suitably used as a dye-sensitized solar cell electrode or gas sensor material that requires a high specific surface area in order to adsorb a large amount of the dye and gas molecules.
  • FIG. 5 shows transmission electron microscope (TEM) photographs at various temperatures (450 ° C., 500 ° C., and 550 ° C.) of titanium oxide nanotubes doped with Mn. From this, it was confirmed that at least 450 ° C, the structure of the acid-titanium nanotubes was stably maintained.
  • TEM transmission electron microscope
  • Test 3 UV-visible, spectroscopic analysis
  • a 0.5 mol% Mn 3 + -doped acid titanium nanotube was produced according to the method described in Example 1.
  • pure titanium oxide nanotubes without any doping and a mixed powder of 1: 1 (weight ratio) of Mn 2 O and pure acid titanium nanotubes were prepared.
  • UV-visible spectroscopic analysis was performed as follows. For each of the above three samples Subsequently, the reflectance (Reflectance:%) was measured by a diffuse reflection method using a U-4100 spectrophotometer manufactured by Hitachi, Ltd. The measurement wavelength range was 300 to 800 nm, the wavelength operation speed was 300 nm / min, and the sampling interval was 1.0. The results are shown in Fig. 6.
  • the Mn-doped titanium oxide nanotubes are not present in the lattice of the nanotubes where the added manganese is present in the nanotube as an ion or adsorbed on the surface, or is present as a metal element. It can be understood that they exist in the form of solid solution as ions.
  • Test Example 4 Powder X-ray analysis
  • a 0.5 mol% Mn 3 + -doped acid titanium nanotube was produced according to the method described in Example 1.
  • pure oxide titanium nanotubes with no doping were prepared.
  • Powder X-ray diffraction analysis was performed as follows. Each of the above two samples is attached to a glass specimen holder, and using a rotating anti-cathode intense X-ray generator (Rigaku, RU-200B system), a CuKa line (wavelength 0.154056 nm) ) And diffraction angle 2 ⁇ is 2. The diffraction pattern was measured in the range of 60 ° to 60 °. The sampling angle was 0.01 °, the sampling rate was 4 ° / min, and the diverging slit, scattering slit, and light receiving slit were 0.5 °, 0.5 °, and 0.15 °, respectively. The results are shown in Fig. 7.
  • Mn is an ion, that is, Mn 3+ in the titanium oxide nanotube lattice. It can be concluded that it exists in solid solution.
  • Test Test Example 5 (Photocatalytic Activity Test, Test)
  • the photocatalytic activity was evaluated by a hydrogen production test by light irradiation.
  • As test samples undoped titanium oxide nanotubes, 0.5 mol% V 5+ doped oxide titanium nanotubes and 0.5 mol% Nb 5+ doped titanium oxide nanotubes obtained in Example 1, and comparative examples
  • Commercially available acid titanium powder (Degussa P-25 and Ishihara Sangyo ST-01) was used. For titanium oxide nanotubes! All of these were heat-treated at 400 ° C for 3 hours.
  • the hydrogen generation amount (ie, photocatalytic performance) of the acid-titanium nanotube (3) is the same as that of commercially available acid-titanium powder (P-25 (l) and ST-0K2)). It was confirmed that the photocatalytic performance of titanium oxide was improved by increasing the nanotube structure by a factor of 2 to 3 times. Furthermore, V 5+ doped titanium oxide nanotubes (4) and Nb 5+ doped titanium oxide nanotubes (5) were observed to generate more hydrogen than pure nanotubes (3). It was done. That is, it was confirmed that the nanotubes (4) and (5) in which the metal cation was dissolved in the lattice of the tube exhibited very excellent photocatalytic performance.

Abstract

L’invention concerne un nanotube d’oxyde de titane dopé d’un ion de métal de faible résistivité, de conductivité appropriée et de plus grande résistance thermique ; et un procédé de fabrication idoine. Elle porte sur un nanotube d’oxyde de titane dopé d’un ion de métal de rayon ionique compris entre 0,035 et 0,15 nm (en particulier entre 0,05 et 0,07 nm). Elle concerne en outre un procédé de fabrication d’un nanotube d’oxyde de titane dopé d’un ion de métal, comprenant la phase (1) de mélange d’une poudre d’oxyde de titane avec un composé de métal contenant un ion de métal de rayon ionique compris entre 0,035 et 0,15 nm (en particulier entre 0,05 et 0,07 nm) dans une proportion telle que le rapport de l'ion de métal à l'ion de titane (Ti4+) de la poudre d’oxyde de titane entre dans la fourchette de 0,01 à 5 % molaire pour ainsi réaliser un traitement alcalin, et la phase (2) consistant à soumettre de manière séquentielle le produit de réaction obtenu à un lavage à l’eau, à une neutralisation et à un séchage.
PCT/JP2005/017013 2005-02-17 2005-09-15 Nanotube d’oxyde de titane et procédé de fabrication idoine WO2006087841A1 (fr)

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JP2007012503A (ja) * 2005-07-01 2007-01-18 Nippon Oil Corp 光電変換素子
CN101190801B (zh) * 2006-11-22 2010-05-12 北京航空航天大学 用离子交换法制备金属离子掺杂二氧化钛线管材的方法
WO2010084645A1 (fr) * 2009-01-20 2010-07-29 財団法人神奈川科学技術アカデミー Catalyseur acide solide ayant une structure de nanotube
CN101891146A (zh) * 2010-07-01 2010-11-24 淮阴工学院 一种磁性掺杂二氧化钛纳米管的制备方法
WO2013004560A1 (fr) * 2011-07-06 2013-01-10 Deutsches Zentrum für Luft- und Raumfahrt e.V. Procédé de fabrication de nanotubes de tio2 semi-conducteurs de type p
JP2014165090A (ja) * 2013-02-27 2014-09-08 Osaka Gas Co Ltd 光電変換素子用ペースト組成物、並びにそれを用いた光電変換素子用電極及び光電変換素子
KR101912892B1 (ko) 2017-07-11 2018-10-29 한국과학기술원 다공질의 금속산화물 나노튜브 제조 방법, 이를 통해 제조된 다공질의 금속산화물 나노튜브 및 다공질의 금속산화물 나노튜브를 포함하는 가스 센서

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WO2003053851A2 (fr) * 2001-07-20 2003-07-03 President And Fellows Of Harvard College Nanofils en oxydes de metaux de transition et dispositifs les integrant
JP2003236377A (ja) * 2002-02-13 2003-08-26 Toyota Motor Corp 水性ガスシフト反応触媒

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JP3513738B2 (ja) * 1996-09-30 2004-03-31 中部電力株式会社 ナノチューブ体のチタニアの製造方法

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WO2003053851A2 (fr) * 2001-07-20 2003-07-03 President And Fellows Of Harvard College Nanofils en oxydes de metaux de transition et dispositifs les integrant
JP2003236377A (ja) * 2002-02-13 2003-08-26 Toyota Motor Corp 水性ガスシフト反応触媒

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007012503A (ja) * 2005-07-01 2007-01-18 Nippon Oil Corp 光電変換素子
CN101190801B (zh) * 2006-11-22 2010-05-12 北京航空航天大学 用离子交换法制备金属离子掺杂二氧化钛线管材的方法
WO2010084645A1 (fr) * 2009-01-20 2010-07-29 財団法人神奈川科学技術アカデミー Catalyseur acide solide ayant une structure de nanotube
CN101891146A (zh) * 2010-07-01 2010-11-24 淮阴工学院 一种磁性掺杂二氧化钛纳米管的制备方法
CN101891146B (zh) * 2010-07-01 2012-11-21 淮阴工学院 一种磁性掺杂二氧化钛纳米管的制备方法
WO2013004560A1 (fr) * 2011-07-06 2013-01-10 Deutsches Zentrum für Luft- und Raumfahrt e.V. Procédé de fabrication de nanotubes de tio2 semi-conducteurs de type p
JP2014165090A (ja) * 2013-02-27 2014-09-08 Osaka Gas Co Ltd 光電変換素子用ペースト組成物、並びにそれを用いた光電変換素子用電極及び光電変換素子
KR101912892B1 (ko) 2017-07-11 2018-10-29 한국과학기술원 다공질의 금속산화물 나노튜브 제조 방법, 이를 통해 제조된 다공질의 금속산화물 나노튜브 및 다공질의 금속산화물 나노튜브를 포함하는 가스 센서

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