CN101495544B - Long-lived high volumetric activity photocatalysts - Google Patents
Long-lived high volumetric activity photocatalysts Download PDFInfo
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- CN101495544B CN101495544B CN200780028506.1A CN200780028506A CN101495544B CN 101495544 B CN101495544 B CN 101495544B CN 200780028506 A CN200780028506 A CN 200780028506A CN 101495544 B CN101495544 B CN 101495544B
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- 239000011941 photocatalyst Substances 0.000 title claims abstract description 100
- 230000000694 effects Effects 0.000 title description 12
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 84
- 238000000034 method Methods 0.000 claims abstract description 23
- 230000001699 photocatalysis Effects 0.000 claims abstract description 21
- 239000011148 porous material Substances 0.000 claims abstract description 14
- 239000002019 doping agent Substances 0.000 claims abstract description 12
- 239000002245 particle Substances 0.000 claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 claims abstract description 8
- 239000002184 metal Substances 0.000 claims abstract description 8
- 229910052755 nonmetal Inorganic materials 0.000 claims abstract description 8
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 5
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 5
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 81
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 45
- 239000002159 nanocrystal Substances 0.000 claims description 35
- 238000001354 calcination Methods 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 17
- 230000007547 defect Effects 0.000 claims description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 229910001868 water Inorganic materials 0.000 claims description 11
- 238000009826 distribution Methods 0.000 claims description 9
- 239000012530 fluid Substances 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 239000010936 titanium Substances 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical group [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 5
- 239000011135 tin Substances 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000007146 photocatalysis Methods 0.000 claims description 4
- 238000000746 purification Methods 0.000 claims description 4
- 239000004065 semiconductor Substances 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 238000006555 catalytic reaction Methods 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 2
- 229910052779 Neodymium Inorganic materials 0.000 claims description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 2
- 229910052735 hafnium Inorganic materials 0.000 claims description 2
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 239000011733 molybdenum Substances 0.000 claims description 2
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 2
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- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 239000010937 tungsten Substances 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- 239000011701 zinc Substances 0.000 claims description 2
- 239000003570 air Substances 0.000 claims 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims 1
- 239000013078 crystal Substances 0.000 abstract description 37
- 239000004408 titanium dioxide Substances 0.000 abstract description 16
- 238000012546 transfer Methods 0.000 abstract description 8
- 239000000356 contaminant Substances 0.000 abstract description 3
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- NBBJYMSMWIIQGU-UHFFFAOYSA-N Propionic aldehyde Chemical compound CCC=O NBBJYMSMWIIQGU-UHFFFAOYSA-N 0.000 description 34
- UQEAIHBTYFGYIE-UHFFFAOYSA-N hexamethyldisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)C UQEAIHBTYFGYIE-UHFFFAOYSA-N 0.000 description 19
- -1 OH Chemical class 0.000 description 18
- 230000009849 deactivation Effects 0.000 description 18
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- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 230000002745 absorbent Effects 0.000 description 6
- 239000002250 absorbent Substances 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 231100000719 pollutant Toxicity 0.000 description 6
- 238000000634 powder X-ray diffraction Methods 0.000 description 6
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- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
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- 230000010718 Oxidation Activity Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
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- 230000015572 biosynthetic process Effects 0.000 description 2
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- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910008449 SnF 2 Inorganic materials 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
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- WEUCVIBPSSMHJG-UHFFFAOYSA-N calcium titanate Chemical compound [O-2].[O-2].[O-2].[Ca+2].[Ti+4] WEUCVIBPSSMHJG-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- JYYOBHFYCIDXHH-UHFFFAOYSA-N carbonic acid;hydrate Chemical compound O.OC(O)=O JYYOBHFYCIDXHH-UHFFFAOYSA-N 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
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- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical group [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 230000001877 deodorizing effect Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
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- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L9/00—Disinfection, sterilisation or deodorisation of air
- A61L9/16—Disinfection, sterilisation or deodorisation of air using physical phenomena
- A61L9/18—Radiation
- A61L9/20—Ultraviolet radiation
- A61L9/205—Ultraviolet radiation using a photocatalyst or photosensitiser
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- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Catalysts (AREA)
Abstract
The present invention relates to nanocrystalline titanium dioxide (TiO2) photocatalysts having nanocrystallites of less than 14 nanometers in diameter, which are substantially defect-free. The TiO2 photocatalysts form porous particles having a very large mass transfer surface area, large cylindrical pores, and low mass transfer resistance. The nanocrystalline TiO2 photocatalysts provide at least 75% of the photocatalytic activity of commercially-available TiO2 crystals having diameters greater than 20 nm. The nanocrystalline TiO2 photocatalysts may be doped with a metal, metal oxide, or non-metal dopant. The invention discloses a process for preparing the nanocrystalline TiO2 photocatalysts. The present invention also provides methods for using nanocrystalline TiO2 photocatalysts to remove contaminants.
Description
The cross reference of related application
The rights and interests of the PCT application PCT/US2007/012820 that the exercise question that the application submits on May 31st, 1 is " long-lived heavy body active photocatalyst (LONG-LIVED HIGH VOLUMETRIC ACTIVITYPHOTOCATALYSTS) ", the U.S. Provisional Application the 60/809th that the exercise question of this application submission on June 1st, 1 is " nano-crystalline titanium dioxide ultraviolet light catalyst (NANOCRYSTALLINE TITANIUM DIOXIDEULTRAVIOLET) ", the U.S. Provisional Application the 60/809th that the exercise question of submitting in No. 899 and on June 1st, 2006 is " filter for installation (FILTERDEVICES HAVING DEACTIVATION RESISTANTPHOTOCATALYSTS) with deactivation resistant photocatalyst ", the rights and interests of No. 995
Background of invention
1. invention field
In general, the disclosure relates to by titanium dioxide (TiO
2) photocatalyst made of nanocrystal.More specifically, this TiO
2the diameter of nanocrystal is less than 14 nanometers (nm), and treated at utmost to reduce TiO
2subsurface defect in nanocrystal.The disclosure provides the preparation method and has used this nanocrystalline TiO
2photocatalyst photochemical catalysis pollutent purifying air, the method for water or other fluids.
2. association area explanation
Photochemical catalytic oxidation (PCO) is a technology of eliminating by the chemical action that makes to use up or reducing such as pollutant level in air or water or other fluid (or other fluids).When using ultraviolet (UV) photoluminescence catalyzer, this technology more specifically can be described as ultraviolet catalytic oxidation (UV-PCO).
Room air can comprise micro-pollutent, comprises carbon monoxide, ozone and volatile organic matter (VOC), as formaldehyde, toluene, propionic aldehyde (propanal), butylene, propionic aldehyde (propionaldehyde) and acetaldehyde.Use the air purifier of UV-PCO technology to can be used for these pollutant chemistries are changed into to the little product of harm, as carbonic acid gas and water, and/or the low polluted product that is easier to remove from air than their parent compound.
Other method is for removing airborne pollutent.Adopt the absorbent air filters of absorbent material by being trapped in filter hole by pollutent and allowing clean air remove airborne pollutent by strainer, these absorbent materials are such as but not limited to gac, clay or mesopore zeolite.A distinct disadvantage of absorbent filter is that this strainer only blocks or hold back pollutent and strainer is easily blocked, and absorbent air filters often can not effectively remove certain class source of the gas pollutent, as ozone or carbon monoxide.
Comprise titanium dioxide (TiO
2), zirconium dioxide (ZrO
2), zinc oxide (ZnO), calcium titanate (CaTiO
3), tindioxide (stannic) (SnO
2), molybdic oxide (MoO
3) and the photocatalyst with semiconductor active of analogue be used in air-purification system for eliminating airborne organic pollutant.In these photocatalysts, due to its chemical stability, relatively low cost and be suitable for by the electronic band gap of UV-light photoactivation titanium dioxide (TiO
2) be one of the most widely used semiconductor light-catalyst.
Be used as at present the TiO of air purifying preparation
2the shortcoming of photocatalyst is the reduction of performance under the accumulation, wet condition of incomplete oxidation product, mass transfer problem, the TiO in the high flow rate system
2the inactivation of photocatalyst and inorganic pollution.
Titanium dioxide TiO
2it is the oxidised form that transition metals Ti is the most stable.TiO
2mainly by Ti
+ 4positively charged ion and O
-2the ionic material that negatively charged ion forms.The TiO of powder type
2be white and give coating, paper, textiles, printing ink, plastics, toothpaste and makeup white industrial being widely used in.Say TiO from crystalline form
2mainly with a kind of existence the in three kinds of different polymorphics: rutile, anatase octahedrite and brookite.TiO
2two kinds of more common polymorphics be that rutile and anatase octahedrite have tetragonal structure, and TiO
2more rare brookite form has the orthorhombic body structure.
Report, when by UV-irradiation, at TiO
2three kinds of polymorphics in, TiO
2anatase form (low temperature form) there is maximum photocatalytic activity.This may be wider optical absorption band and the sub-virtual mass of small electric because of anatase form, thereby causes the mobility that current carrier is higher.Higher than the about temperature of 600 ℃, anatase octahedrite can change into rutile, during follow significantly reducing of grain growing and surface-area.
The every single cell of the crystalline structure of rutile and anatase octahedrite all has 6 atoms.Anatase form is that body-centred structure and its conventional structure cell comprise two single cells (i.e. 12 atoms).For rutile and two kinds of forms of anatase octahedrite, titanium atom is shared limit and angle mutually mode with adjacent each octahedra unit is arranged in crystalline structure.With each Liang Tiao limit, octahedra unit in rutile structure, be to share limit to compare, anatase structured in the four edges of each octahedra unit be to share limit.
As crystal TiO
2when photocatalyst is less than the photon irradiation of UV-light of 387nm (under room temperature), surpassed TiO
2band-gap energy (3.2eV), excited electronics in one of semiconductor molecule track from valence band " transition " to conduction band, therefore at valence band generation electronics " hole ".The electron-hole pair produced by this way is considered to move to surface, they and the pollutent generation redox reaction that is adsorbed to photocatalyst surface on this surface.
The electronics of " transition " is final and electronics " hole " is compound and turn back to valence band.According to following assumed response, between the separation period of electron hole, electronics is considered to react with molecular oxygen, and the electronics in valence band " hole " is considered to react with surface hydroxyl, forms respectively hydroxyl (OH) and peroxide radical:
OH
-+ h
+(" hole ") → OH (hydroxyl radical free radical)
O
2+ e
-(" transition " electronics) → O
2 -2(peroxy radical)
A kind of at present TiO of obtainable tool activity
2photocatalyst, as DEGUSSAP25 (hereinafter being called " P25 ") (goldschmidt chemical corporation, Field park, Ritchie, New Jersey, the U.S.), by about 20 nanometers (nm) the anatase octahedrite TiO of 80 % by weight
2crystal and about larger (about 40nm) rutile TiO of 20 % by weight
2crystal composition.The preparation of employing high temperature process, the P25 crystal has the perfection of lattice (crystalline perfection) of enough degree so that separate enough electron holes and grain surface is arrived in electronic migration.The hole on surface is than ozone or the chlorine hydroxyl radical free radical of strong oxidizer (OH) form more.The electronics on surface can, by the reduction of molecular oxygen, may be by superoxide ion O
2 -formation and further be reduced to superoxide O subsequently
2 -2form levels of reactive oxygen species.Under the existence of oxygen and water, hydrogen peroxide is at the TiO of photocatalytic activity
2upper formation.Hydrogen peroxide is considered to the Main Function thing (agent) of long-range photochemical catalytic oxidation (PCO), and this long-range photochemical catalytic oxidation has been described and photosensitive TiO
2approach very much but be not the physically directly oxidation of the material of contact.Use the TiO of anatase form
2the formaldehyde available oxygen is changed into to CO
2and H
2o needs the existence of hydroxyl radical free radical and levels of reactive oxygen species.
With respect to thering is 10nm average crystal grain size and being greater than 100m
2the less TiO of/g surface-area
2crystal grain, have about 20nm average crystal grain size and about 50m
2the P25 crystal grain of/g BET surface-area is seemingly in theoretical inferior position.The BET used at this is (with the first letter name of Stephen Brunauer, P.H.Emmett and Edward Teller three surname, Journal of theAmerican Chemical Society, 1938, vol.60, pp.309-319) be that in Surface Science, the widely used physical absorption by gas molecule is calculated the long-pending method of solid surface.
Table 1 provides the comparison of average crystal grain size with various surface area measurements, comprises TiO
2anatase form and rutile form.
Table 1
The average crystal grain size, surface-area/skeleton volume, effective surface area specific surface area, specific surface area
Nm m
2/ cm
3m
2/ cm
3m
2/ g anatase octahedrite m
2/ g rutile
5 1200 800 208 188
6 1000 667 174 156
7 857 571 149 134
8 750 500 130 117
9 667 444 116 104
10 600 400 104 94
11 545 364 95 85
12 500 333 87 78
13 462 308 80 72
14 429 286 74 67
15 400 267 69 63
16 375 250 65 59
17 353 235 61 55
18 333 222 58 52
19 316 211 55 49
20 300 200 52 47
21 286 190 50 45
22 273 182 47 43
23 261 174 45 41
24 250 167 43 39
25 240 160 42 38
27 222 148 39 35
29 207 138 36 32
31 194 129 34 30
33 182 121 32 28
35 171 114 30 27
37 162 108 28 25
39 154 103 27 24
40 150 100 26 23
Yet, even as shown in table 1, reduce anatase form and rutile form TiO
2average crystal grain size can increase TiO
2specific surface area, but because heterogeneous catalyst surface phenomena normally, this generally can not cause the work-ing life that higher photocatalytic activity or photocatalyst are longer, as people, should rationally estimate.Explain a TiO that hypothesis is less crystal grain of this phenomenon
2have and can impel electron hole compound defect and shortcoming fast.Refer to, as Zhang, Z., etc., J.Phys.Chem.B, 1998, vol.102, pp.10871-10878, show to use as Fe
+ 3or Nb
+ 5the anatase octahedrite TiO of ion doping
2crystal grain has increased photocatalytic activity.These hotchpotchs that are positioned at crystal grain are held back the electronics of photon-generation, thereby postpone electron-hole recombination.The support of relation between the consumption of the hotchpotch that this hypothesis obtains having reported (active for improving) and character and anatase crystal grain size.
For destroying the TiO of VOCs
2photocatalytic oxidation activity in another factor be increased resistance to mass transfer, this resistance to mass transfer appears to adopt has high surface area but the TiO of small-bore
2the time.Fine porosity is diffused into avtive spot by inhibition VOCs and limits the photocatalytic activity site.
In the situation that the destruction of VOCs causes non-volatile ash content to form, as siloxanes is oxidized to CO
2, H
2o and SiO
2, this ash content can seal avtive spot (VOC is oxidized at this avtive spot), and has limited and enter at Catalytic Layer other avtive spots of depths more.
Therefore, current obtainable TiO
2photocatalyst has and calculates with unit weight that photocatalytic activity is poor, per unit is easily utilized the shortcoming that activity lower, actual service life short of surface-area for removal of pollutants.
The disclosure has overcome TiO in the past
2or doped Ti O
2these shortcomings of photocatalyst.
Summary of the invention
The disclosure provides has the nano-crystalline titanium dioxide (TiO that diameter is less than the nanocrystal of 14nm
2) photocatalyst.
By nanocrystalline TiO
2photocatalyst is prepared or processes at utmost to reduce TiO
2subsurface defect in nanocrystal.In addition, the photocatalyst aggregate has the pore structure of low mass transfer resistance, makes TiO
2the more anti-inactivation caused due to environmental pollutant (as siloxanes) of photocatalyst.
When the air having sufficient ultraviolet radiation and enough relative humidity exists, the disclosure also provides TiO
2nanocrystal, the photocatalytic activity of this nanocrystal is at least the commercially available TiO that comprises larger diameter crystal grain
2at least 75% of photocatalyst.
The disclosure further provides TiO
2nanocrystal, this TiO
2nanocrystal has one or more metals, metal oxide, nonmetal or other hotchpotchs or surface treatment agent as Tungsten oxide 99.999 in conjunction with (doping).
The disclosure also further provides, by producing the levels of reactive oxygen species of hydroxyl radical free radical and oxidation normal air pollutent, nanocrystalline TiO
2photocatalyst can be used in air purifier system eliminating airborne pollutent.
Nanocrystalline TiO of the present disclosure
2photocatalyst also can be used as the photo catalysis air purifying system of anti-siloxanes and uses for the part of the purification system of water or other fluid.
The accompanying drawing summary
Fig. 1 provides the figure of the dull and stereotyped inherent speed reactor in laboratory.
Fig. 2 has illustrated under the existence of 90 parts of every 1,000,000,000 (ppb) hexamethyldisiloxane various based on TiO
2life-span of photocatalyst.
Fig. 3 has illustrated the pore size distribution overview that compares disclosure photocatalyst with other photocatalysts.
Fig. 4 has illustrated disclosure TiO
2the X-ray powder diffraction figure of photocatalyst UV114, UV114 has the anatase crystal grain of 122 dusts (12nm).
Fig. 5 has illustrated disclosure TiO
2the X-ray powder diffraction figure of photocatalyst 2UV27,2UV27 has the anatase crystal grain of 110 dusts (11nm).
Fig. 6 has illustrated the X-ray powder diffraction figure of the extraneous photocatalyst UV139 of the disclosure, and UV139 has the anatase crystal grain of 188 dusts (19nm).
Fig. 7 has illustrated the impact of various hexamethyldisiloxane concentration on the 2UV27 of anti-siloxane catalyst deactivation rate.
Fig. 8 has illustrated the two kinds of burnt TiO of the present disclosure that compare with commercially available P25 deactivation rate
2the figure of photocatalyst deactivation rate.
Detailed Description Of The Invention
The disclosure provides by the nano-crystalline titanium dioxide (TiO that has diameter and be less than the nanocrystal of 14 nanometers (nm)
2) photocatalyst made.Term " nanocrystal " and " crystal grain " are used interchangeably in this application, and their relational language also is used interchangeably as " nanocrystalline " and " crystal ".Nanocrystalline TiO
2photocatalyst forms has the porous particle of the pore structure that is conducive to low mass transfer resistance, and has ultraviolet (UV) Photocatalytic oxidation activity of the inactivation that anti-environmental pollutant (as siloxanes) cause.Nanocrystalline TiO
2photocatalyst can be doped with one or more metals, metal ion, nonmetal or other hotchpotchs, or have surface treatment agent as Tungsten oxide 99.999.
By TiO
2crystal grain is prepared or processes to reduce or at utmost reduce TiO
2subsurface defect in crystal grain.An example of this processing is such method, at the temperature higher than 250 ℃, preferably between 350 ℃ to 450 ℃, in oxygen-containing atmosphere by TiO
2crystal grain annealing at least 24 hours.This time is to reducing TiO
2subsurface defect in structure is enough but just causes that on a large scale (large-scale) changes into rutile form and the surface-area that brings thus reduces the time and falls short of from anatase form.
Nanocrystalline TiO of the present disclosure
2photocatalyst is connected to form hole by their summit and/or limit.The pore structure formed thus is conducive to low mass transfer resistance.TiO
2the most surfaces of photocatalyst aggregate is amassed at diameter and is greater than in 5nm or larger hole.At least 200 meters of photocatalyst aggregate
2surface-area/centimetre
3(m
2/ cm
3) the skeleton volume is greater than in 6nm or larger hole at diameter.TiO
2the overall distribution of photocatalyst aggregate mesoporous has 10nm or larger pattern, and wherein pattern is used to refer to number or the size the most often occurred in group.This pore structure produces the TiO of the inactivation that anti-environmental pollutant (as siloxanes) cause
2photocatalyst.
Have in the environment of enough relative humidity in air and activating TiO
2under the sufficient ultraviolet radiation of photocatalyst exists, nanocrystalline TiO of the present disclosure
2it is at present obtainable containing larger diameter TiO that photocatalyst provides
2at least 80% photocatalytic activity of photocatalyst (as DEGUSSA P25).
Nanocrystalline TiO
2photocatalyst can be used in air purifier system eliminates airborne pollutent, when contacting with UV-light while being activated, by producing hydroxyl radical free radical and the levels of reactive oxygen species that can be reacted with common contaminants (as VOCs), these pollutant chemistries are changed into to the little material of harm, as water, carbonic acid gas and molecular oxygen, or changing into the low pollution compound that other are easier to remove than their parent compound from airflow, described VOCs comprises formaldehyde, toluene, propionic aldehyde (propanal), butylene, propionic aldehyde (propionaldehyde) and acetaldehyde.
Nanocrystalline TiO of the present disclosure
2photocatalyst also can be used for air-purification system, and Air quality is produced to photoinduction deodorizing, antibiotic and self-cleaning effect.Nanocrystalline TiO
2photocatalyst can be used in air-purification system airborne pollutent is changed into the little compound of harm.
Also can adopt with described herein and purify same mode for air (or other gases), the purification by nano-crystalline photocatalysis agent of the present disclosure for water and/or other fluids.
The disclosure provides has the TiO that diameter is 14nm or less nanocrystal size
2the photocatalyst nanocrystal, this nanocrystal can have metal, metal oxide, nonmetal or other hotchpotchs in conjunction with (doping).Dopant material can be used as coating or layer is added to TiO
2in.At disclosure doped Ti O
2in an embodiment of photocatalyst, according to Ti
(1-X)m
xo
2ratio by TiO
2with dopant, be combined, wherein X is molar percentage or molar fraction, and M is dopant material.In one embodiment, molar fraction is less than 0.1.Be added in this embodiment TiO
2the hotchpotch of photocatalyst can promote pollutent to eliminate in every way, comprises and makes TiO
2photocatalyst has more activity under the light (as visible ray) of wider scope; Reduce the energy barrier of pollutent; As oxide catalyst; Promote pollutent to absorb the surface of photocatalyst; And/or, compared to independent use titanium dioxide optical catalyst, make TiO
2photocatalyst is more insensitive on the impact of humidity.
Can be used as TiO
2the metal of the hotchpotch of photocatalyst includes but not limited to tin, iron, zinc, niobium, tungsten, neodymium, cerium, molybdenum, hafnium and/or its any combination.
Can be used as TiO
2nonmetal nitrating titanium dioxide or the TiO of including but not limited to of the hotchpotch of photocatalyst
2-Xn
x.
In addition, nanocrystalline TiO of the present disclosure
2photocatalyst can have surface treatment agent, for example Tungsten oxide 99.999.
Another embodiment of the present disclosure is to be less than the TiO of 12nm by diameter
2the photocatalyst that nanocrystal is made.Preferred embodiment has the TiO that diameter is less than 12nm
2nanocrystal, this nanocrystal is connected to form by summit and limit the porous particle that diameter is less than 1 micron, and wherein most of porous particle surface-area is all in 5nm or larger hole at diameter.Nanocrystalline TiO
2at least 200 meters of preferred structures
2surface-area/centimetre
3the skeleton volume is greater than the hole of 6nm at diameter, have 10nm or larger pore size distribution pattern.Preferred embodiment has mean pore size and is greater than 5nm and diameter for forming the TiO of described particle
2the 10-25 of nanocrystal size porous particle doubly.
As mentioned above, by UV-irradiation TiO
2the hydroxyl radical free radical (OH) that photocatalyst forms is extremely strong oxygenant (has relative SHE[standard hydrogen electrode]+redox-potential of 2.8eV), and can the nearly all organic compound of oxidation.By relatively, the redox potential of conventional oxidant chlorine and ozone is respectively+1.36eV and+2.07eV.When air or water pollutant absorb UV-activated TiO
2in the time of on photocatalyst, hydroxyl radical free radical is attacked and this pollutent of oxidation, and by this pollutant chemistry change into water, carbonic acid gas and other usually harm little and/or be easier to the material of removing from airflow or fluid flow than their parent compound.Therefore, be chemically converted into the little product of harm by the technique pollutent, rather than hold back simply and concentrate on strainer, realize thus more effective cleaning air, water or other fluids.
Separate electron hole used herein, is restricted to electronics from valence band " transition " to the time conduction band, produces electronics " hole " in valence band, until electronics and electron-hole recombination are returned to valence band.Usually be about 10 the mean time (also referred to as the life-span of current carrier) that separate electron hole
-9to 10
-6second.
Valence band also can be described as highest occupied molecular orbital (HOMO), and conduction band also can be described as lowest unoccupied molecular orbital (LUMO).Therefore, the transition of electronics from valence band to more high-octane conduction band also can be described as TiO
2hOMO in electronics be less than 387nm by wavelength optical excitation " transition " to LUMO.
Crystal TiO
2the defect of inside configuration can disturb electron hole to separate, thereby reduces nanocrystalline TiO
2photocatalytic activity.Subsurface defect is easy to hold back electronics and stops them to enter conduction band, otherwise electronics can react with oxygen at conduction band superoxide and the hydroxyl radical free radical that forms oxidable air pollutant.The crystal inside defect also can shorten disengaging time, and can reduce photocatalytic activity.On the contrary, the defect on the small-crystalline outside is estimated to improve nanocrystalline TiO
2photocatalytic activity.As mentioned above, by nanocrystalline TiO
2photocatalyst annealing can reduce the crystal inside defect and improve thus photocatalytic activity.
Nanocrystalline TiO of the present disclosure
2photocatalyst can be used as the part of UV-PCO reactor or air-purification system.Nanocrystalline TiO
2photocatalyst also can be used for having adopted prevention or overcomes TiO
2in the UV-PCO reactor of photocatalyst inactivation technology.The UV-PCO reactor has the advantage that can under room temp, operate, produce insignificant pressure drop, low power consumption operation and need the long life of less maintenance.TiO of the present disclosure
2nanocrystal maintains usually and TiO
2relevant semi-conductivity is fully flawless.
When adopting for example low temperature synthesis mode synthesizing nanocrystalline TiO of the sol-gel method of template mediation
2when (thering is large surface-area and large hole), the TiO synthetic with the employing high temperature process
2compare, the nanocrystalline material of low temperature method gained is considered to have the crystal inside defect of greater concn.This crystal inside defect has reduced nanocrystalline TiO
2photocatalytic activity.Yet, nanocrystalline TiO
2photocatalytic activity can by oxygen-containing atmosphere by TiO
2photocatalyst calcining time enough increases.Under certain condition by TiO
2the crystal grain heating can make oxygen leave crystalline structure, and this usually causes the increase of crystal inside defect.Yet, for example, in clean oxygen environment (, not the gas of siliceous pollutent) by TiO
2the crystal grain heating can produce substantially flawless TiO
2crystal grain.
In this method, TiO
2preferably under the calcining temperature higher than 200 ℃, calcine 24 to 72 hours, and more preferably most calcination time is in approximately calcining between 350 ℃ and 450 ℃.Perhaps, method for calcinating can be used higher temperature to shorten calcination time; For example, but calcining step use temperature from approximately paramount 550 ℃ 5 hours or shorter, preferably temperature from approximately 450 ℃ to approximately maintaining approximately 3 hours to 5 hours 550 ℃.During the short period, can optionally further heat TiO when calcining
2so that annealing is other approximately 24 hours to approximately 72 hours under the temperature from about 350 ℃ of temperature and 450 ℃.In this process, calcination atmosphere should be without the silicon pollutent.If the calcining medium contains water vapor, it should not contact the silicon fire resistive material that contains of heat.
With reference to accompanying drawing, particularly Fig. 1 provides laboratory dull and stereotyped inherent speed reactor 8.Reactor 8 has VOC supply 1 and VOC mass flow controller 2.Reactor 8 has the nitrogen supply device 3 reinforced to bubble device 4, and reinforced to moist nitrogen mass flow controller 5 subsequently.Reactor 8 also has oxygen supply 6 and oxygen mass flow controller 7.Reactor 8 has through machining aluminium block 9, is useful on the bed 10 of the sheet (slide) 11 that scribbles catalyzer on the machining aluminium block at this.Reactor 8 has in order to mix and to disperse the granulated glass sphere 12,13 of gas.Gas in reactor 8 is analyzed by gas-analysis apparatus 14.Reactor has the rate of flow meter of giving vent to anger 15.Reactor 8 has a UV A lamp 17 and the 2nd UV A lamp 18.The height of lamp can be regulated by lamp height adjuster 16.
Will be to according to the nanocrystalline TiO with high surface area and macroporous structure of the present disclosure
2exemplary tested and with DEGUSSA P25TiO
2deactivation rate compare, acquired results provides in the following embodiments.
For embodiment, under the condition of the approximately initial oxidation of 20% propionic aldehyde (propanal) quilt, under 50% relative humidity (RH), 1ppm propionic aldehyde (propanal) is by the UV-A photoxidation.Deactivator is the hexamethyldisiloxane of 90 parts every 1,000,000,000 (ppb).
Under this condition, with they separately initial photocatalytic activity compare, the 18.5m by pore surface area from P25
2/ g (by the BJH nitrogen adsorption method) is increased to the TiO that mixes tin
2the 77.8m of (being appointed as UV114 of the present disclosure)
2/ g has reduced the deactivation rate (from per hour per hour 0.335% the reduction that is reduced to UV114 of 2.05% (P25)) of photocatalyst.
Therefore, suppose that photochemical catalysis deactivation rate and siloxane concentrations are proportional, approximately, after 24 hours, under the existence of 90ppb hexamethyldisiloxane, the activity of P25 is estimated to drop to 50% of its initial activity.By this result be extrapolated to deactivator than small concentration-1ppb hexamethyldisiloxane, within 90 days, estimate afterwards that the photocatalytic activity of P25 drops to 50% of its initial activity.By relatively, after 550 days, estimate that under the existence of 1ppb hexamethyldisiloxane the photocatalytic activity of UV114 drops to 50% of its initial activity.
In this embodiment, for simplicity, used the conventional BET-specific surface area m of unit of measure
2/ g.Use nanocrystalline TiO
2the sheet of 1 inch * 3 inches of aqeous suspension coatings, and allow its drying.When the inherent speed reactor for Fig. 1, this TiO
2coating is enough to absorb 100% incident light.This reactor is the dull and stereotyped photo catalysis reactor with the UV-irradiation provided by two black lamps (SpectroLine XX-15A).This spectral distribution is symmetrical near about 352nm place intensity peak, and extends to 400mm from 300nm.By adjust between lamp and the sheet glass that scribbles titanium dioxide apart from changing intensity of illumination.The ultraviolet ray intensity of reactor surface is measured by the UVA power meter.Highly purified nitrogen by the water bubbler so that the desired moisture level level to be set.Pollutent from compressed gas cylinder (as propionic aldehyde/N
2) or produce from the Temperature Control Type bubbler.Then, Oxygen Flow in conjunction with nitrogen and contaminant stream to prepare required carrier gas mixture (15% oxygen, 85% nitrogen).
1 inch * 3 inches aluminium flakes that scribble titanium dioxide are placed on the well ground from aluminium block of 1 inch wide 18 inches long.Then cover this well with the quartz window that can see through 96%UVA.Liner between quartz window and aluminium block produces runner (flow passage) above scribbling the sheet glass of titanium dioxide.1 inch wide 2mm is high for this runner.
Contaminated gas enters reactor, and it is at first by glass mixed bead bed.Then, air-flow enters the inlet zone of 1 inch * 2mm, and this inlet zone has enough length (3 inches) to produce full-blown laminar velocity characteristic.Then, air-flow passes through from the glass pane surface that scribbles titanium dioxide.Finally, before leaving reactor, gas is by exit region (3 inches long) and the second granulated glass sphere bed of 1 inch * 2mm.
With reference now to Fig. 2,, under the existence of 90ppb hexamethyldisiloxane, by the inherent speed reactor that uses Fig. 1, determine various based on TiO
2life-span of photocatalyst.Determine the deactivation rate of photocatalyst by the straight slope at representative operation starting stage catalyst performance.The value of P25 is repeatedly the mean value of test.
As shown in data in following table 2, and as shown in Figure 2, when the surface-area in the hole that is more than or equal to 6nm becomes larger, photocatalytic activity loss speed (meaning with % initial activity per hour) has diminished.Yet, by Micrometrics ASAP 2010 surface area test devices, carry out N
2absorption and to the BJH Analysis deterrmination of this absorption this linear relationship be not suitable for total BET surface-area or diameter is greater than the surface-area in the hole of 4nm.
Table 2
| Catalyzer | Activity decreased speed, the % initial activity/hour | BET | BET APD | SA≥ 4nm | SA≥ 5nm | SA≥ 6nm |
| P25 | -2.04 | 52.0 | 8.8 | 25.5 | 20.7 | 18.5 |
| UV139 | -1.45 | 66.6 | 8.9 | 59.2 | 49.8 | 43.5 |
| UV45 | -1.38 | 64.6 | 22.0 | 50.8 | 47.6 | 46.0 |
| 2UV27 | -0.93 | 123.1 | 7.2 | 101.2 | 71.7 | 52.3 |
| 2UV59 | -0.92 | 82.5 | 21.4 | 76.3 | 74.5 | 72.7 |
| UV114 | -0.33 | 99.4 | 21.4 | 85.0 | 80.3 | 77.8 |
With reference now to Fig. 3,, the pore size distribution of photocatalyst P25, UV139 and UV114 is as shown in the relation of aperture (X-axle) and specific surface area (Y-axle).When the pore size distribution data in data based Fig. 3 of table 2 is considered, surface-area and its pattern (being the dominant overwhelming majority) aperture that photocatalyst with minimum deactivation rate not only has in the hole that is greater than 6nm of increase are about 10nm or larger, and can be bimodal, as shown in the chart in UV114 aperture.
Table 2 data presentation, under same UV-irradiation, under the existence of the hexamethyldisiloxane that is 90ppb in concentration, the UV114 that compares the surface-area in the hole that is greater than 6nm with 4.2 times with P25 has the outstanding life-span of at least 6 times for the P25 life-span.The siloxanes that is 2ppb to the time mean concns by these Data Extrapolations, and the hypothesis deactivation rate and Pollutant levels linear, same challenge in the face of siloxanes, after 10000 hours, UV114 will keep at least 20% of its initial activity, and only after 1700 hours P25 prospective damage is fallen to 80% of its initial activity.
Fig. 4 has illustrated the X-ray powder diffraction figure of disclosure photocatalyst UV114Sn (tin), and UV114Sn (tin) is mainly anatase octahedrite and has the crystal grain that diameter is about 12nm (122 dust).
Fig. 5 has illustrated the X-ray powder diffraction figure of disclosure photocatalyst 2UV27, and 2UV27 is also mainly anatase octahedrite and has the crystal grain that diameter is about 11nm (110 dust).
By comparing, Fig. 6 has illustrated the X-ray powder diffraction figure of photocatalyst UV 139, and this photocatalyst size is not included in too greatly in the scope of the present disclosure, and UV 139 is mainly anatase octahedrite and has the crystal grain that diameter is about 19nm (188 dust).As shown in above-mentioned table 2 data, compare 139 pairs of pollutents of UV with UV114 and there is larger deactivation rate.
Fig. 7 has illustrated experimental result, shows the impact of various hexamethyldisiloxane concentration on the 2UV27 of anti-siloxane catalyst deactivation rate.X-coordinate is siloxanes duration of contact, and X-coordinate is normalized to selected hexamethyldisiloxane level (90ppb).The linear scaling factor equals to be multiplied by hexamethyldisiloxane concentration divided by 90 duration of contact.Each catalyst exposure is in the hexamethyldisiloxane different time of controlled level.By using propionic aldehyde (propanal) as probe gas, in the different time, measure termly photocatalytic activity and therefore measure deactivation rate.
As shown in Figure 7, data and curves more trends towards right side, photocatalyst deactivation rate less.Reducing of photocatalyst deactivation rate will be corresponding to the longer photocatalyst life-span.As shown in the data and curves of 34ppb hexamethyldisiloxane and 90ppb hexamethyldisiloxane, the relation between photocatalyst life-span and hexamethyldisiloxane concentration is nonlinear.Therefore, the low concentration of hexamethyldisiloxane causes progressive elongated catalyst life.
For example, under the particular case of the inactivation level corresponding to propionic aldehyde (propanal) activity decreased 50%, when the hexamethyldisiloxane level drops to 34ppb from 90ppb, the photocatalyst life-span is to increase (2.65 corresponding to the linearity of hexamethyldisiloxane concentration rate, with 90, divided by 34, obtain) approximately 1.2 times, the life-span has a net increase of and adds as 3.18 times (1.2 * 2.65).The inference drawn from these data is: for example by the concentration of using absorbent filter to reduce hexamethyldisiloxane, will cause the non-linear increase in photocatalyst life-span.
Anatase octahedrite-the TiO of the high surface area of a plurality of independent batch, great circle column hole
2by with SnF
2additive mixes and calcines preparation in 4 hours and obtain in 500 ℃ of lower air.Be assigned therein as " masterbatch mixture (Master Mix) ".The part of this burnt masterbatch mixture is cooling, pulp and with the described the same manner of embodiment 1 be applied to aluminium flake, drying, and test is active and the activation life-span.Test after 50 hours, the average deactivation rate of this burnt masterbatch mixture be initial one way efficiency (Initial Single Pass Efficiency)/hour 0.32% (%ISPE/hr).The second section of this masterbatch mixture is melted down and anneal 72 hours in 400 ℃ of lower air.Test after 50 hours, the average deactivation rate of calcining annealed masterbatch mixture is 0.08% (%ISPE/hr), Fig. 8 data presentation the obvious improvement on the performance.By comparing, reference catalyst P25DEGUSSA is at corresponding deactivation rate of locating to have 1.6%ISPE in 50 hours.In this case, compare raw catalyst with P25 and demonstrated approximately 2000% improvement on active lifetime.
Although the disclosure is described by reference to one or more exemplary, it will be understood by those skilled in the art that can be in the situation that do not depart from disclosure scope and make various changes and be equal to an alternative key element wherein.
Claims (17)
1. one kind comprises titanium dioxide (TiO
2) photocatalyst of nanocrystal, described titanium dioxide (TiO
2) the nanocrystal diameter is less than 14 nanometers (nm) and is connected to form one or more holes, wherein said TiO by their summit and/or limit
2nanocrystal is to have at least 200m in 6nm or larger hole at diameter
2surface-area/cm
3the skeleton volume, and wherein the pore size distribution pattern is 10nm or larger.
2. the photocatalyst of claim 1, wherein in order to keep TiO
2semiconductor property and the electron hole that is kept for photocatalysis separate, described TiO
2the basic zero defect of nanocrystal.
3. the photocatalyst of claim 1, wherein said TiO
2the diameter of nanocrystal is less than 12nm.
4. the photocatalyst of claim 1, wherein said TiO
2nanocrystal further comprises the coating of dopant material, and described dopant material is selected from metal, metal oxide, nonmetal and any combination.
5. the photocatalyst of claim 1, wherein said TiO
2nanocrystal further comprises the layer of dopant material, and described dopant material is selected from metal, metal oxide, nonmetal and any combination.
6. claim 4 or 5 photocatalyst, wherein by described dopant material and described TiO
2nanocrystal is pressed Ti
(1-X)m
xo
2the ratio combination, wherein Ti is titanium, x is that to be less than 0.1 molar fraction and M be dopant material.
7. claim 4 or 5 photocatalyst, wherein said dopant material comprises metal and any combination thereof that is selected from tin, iron, zinc, niobium, tungsten, neodymium, cerium, molybdenum, hafnium.
8. claim 4 or 5 photocatalyst, wherein said dopant material comprises nonmetal nitrogen.
9. the photocatalyst of claim 3, wherein said TiO
2nanocrystal forms cylindric hole.
10. the photocatalyst of claim 9, wherein said TiO
2nanocrystal forms the porous particle that is less than 1 micron.
11. the photocatalyst of claim 1, wherein said TiO
2nanocrystal forms to have and TiO
2nanocrystalline grain size is the same or than the porous particle in larger aperture.
12. the purification system for air, water or fluid, described purification system comprises the photochemical catalysis TiO that forms porous particle
2nanocrystal, wherein said TiO
2the diameter of nanocrystal is less than 14nm and is connected to form one or more holes, wherein said TiO by their summit and/or limit
2nanocrystal is to have at least 200m in 6nm or larger hole at diameter
2surface-area/cm
3the skeleton volume, and wherein the pore size distribution pattern is 10nm or larger.
A 13. nanocrystalline TiO who prepares substantially without subsurface defect
2the method of photocatalyst, described method comprises:
At the temperature of at least 200 ℃ by nanocrystalline TiO
2the photocatalyst calcining,
Wherein said method for calcinating carries out in containing oxygen and not siliceous atmosphere,
TiO in prepared photocatalyst wherein
2the diameter of nanocrystal is less than 14nm and is connected to form one or more holes, wherein said TiO by their summit and/or limit
2nanocrystal is to have at least 200m in 6nm or larger hole at diameter
2surface-area/cm
3the skeleton volume, and wherein the pore size distribution pattern is 10nm or larger.
14. the method for claim 13, wherein by described nanocrystalline TiO
2photocatalyst calcining 24 to 72 hours.
15. the method for claim 14, wherein by described nanocrystalline TiO
2the photocatalyst calcining, most of calcination time is under the temperature from 350 ℃ to 450 ℃.
16. the method for claim 13, wherein by described nanocrystalline TiO
2photocatalyst was the temperature lower calcination from 450 ℃ to 550 ℃ 3 hours to 5 hours.
17. the method for claim 16, described method further is included in after calcining nanocrystalline TiO
2photocatalyst is annealed other 24 hours to 72 hours under the temperature from 350 ℃ to 450 ℃.
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| US60/809,899 | 2006-06-01 | ||
| PCT/US2007/012820 WO2007143017A1 (en) | 2006-06-01 | 2007-05-31 | Long-lived high volumetric activity photocatalysts |
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| JP6144311B2 (en) * | 2014-09-30 | 2017-06-07 | ソウル バイオシス カンパニー リミテッドＳｅｏｕｌ Ｖｉｏｓｙｓ Ｃｏ．，Ｌｔｄ． | Photocatalytic filter excellent in removal performance for mixed gas and method for producing the same |
| WO2019211787A1 (en) * | 2018-05-02 | 2019-11-07 | Colorobbia Consulting S.R.L. | NITROGEN-DOPED TiO2 NANOPARTICLES AND THE USE THEREOF IN PHOTOCATALYSIS |
| CN111097403B (en) * | 2018-10-26 | 2022-12-13 | 中国科学院金属研究所 | High-valence metal ion doped titanium-based nano material and preparation method and application thereof |
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| US6121191A (en) * | 1996-09-20 | 2000-09-19 | Teruo Komatsu | Ultrafine metal particle carrying photocatalyst, highly function material loaded with the photocatalyst, and method of manufacturing them |
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| CN1765513A (en) * | 2005-10-17 | 2006-05-03 | 武汉理工大学 | Method for preparing homodispersed titanium dioxide photocatalyst on fiberglass surface |
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