WO2005105673A1 - Metal mixed oxide powder containing noble metal - Google Patents
Metal mixed oxide powder containing noble metal Download PDFInfo
- Publication number
- WO2005105673A1 WO2005105673A1 PCT/EP2005/004125 EP2005004125W WO2005105673A1 WO 2005105673 A1 WO2005105673 A1 WO 2005105673A1 EP 2005004125 W EP2005004125 W EP 2005004125W WO 2005105673 A1 WO2005105673 A1 WO 2005105673A1
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- WO
- WIPO (PCT)
- Prior art keywords
- noble metal
- mixed oxide
- oxide powder
- metal
- powder according
- Prior art date
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- 239000000843 powder Substances 0.000 title claims abstract description 48
- 229910000510 noble metal Inorganic materials 0.000 title claims abstract description 47
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 26
- 239000002184 metal Substances 0.000 title claims abstract description 26
- 239000007789 gas Substances 0.000 claims abstract description 13
- 150000002736 metal compounds Chemical class 0.000 claims abstract description 9
- 239000003054 catalyst Substances 0.000 claims abstract description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 6
- 239000001257 hydrogen Substances 0.000 claims abstract description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 5
- 150000001875 compounds Chemical class 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 239000007787 solid Substances 0.000 claims abstract description 4
- 238000000197 pyrolysis Methods 0.000 claims abstract description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- 239000006185 dispersion Substances 0.000 claims description 9
- 229910052697 platinum Inorganic materials 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 5
- 238000002441 X-ray diffraction Methods 0.000 claims description 4
- 238000010586 diagram Methods 0.000 claims description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 239000010931 gold Substances 0.000 claims description 4
- 229910003437 indium oxide Inorganic materials 0.000 claims description 4
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical group [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052763 palladium Inorganic materials 0.000 claims description 3
- 229910001020 Au alloy Inorganic materials 0.000 claims description 2
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- 229910001260 Pt alloy Inorganic materials 0.000 claims description 2
- RLNMYVSYJAGLAD-UHFFFAOYSA-N [In].[Pt] Chemical compound [In].[Pt] RLNMYVSYJAGLAD-UHFFFAOYSA-N 0.000 claims description 2
- 239000003570 air Substances 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 229910052787 antimony Inorganic materials 0.000 claims description 2
- 229910052797 bismuth Inorganic materials 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 239000003353 gold alloy Substances 0.000 claims description 2
- GPYPVKIFOKLUGD-UHFFFAOYSA-N gold indium Chemical compound [In].[Au] GPYPVKIFOKLUGD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052738 indium Inorganic materials 0.000 claims description 2
- 239000011261 inert gas Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 229910052700 potassium Inorganic materials 0.000 claims description 2
- 229910052703 rhodium Inorganic materials 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 229910052708 sodium Inorganic materials 0.000 claims description 2
- 229910052718 tin Inorganic materials 0.000 claims description 2
- 229910001887 tin oxide Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- RHZWSUVWRRXEJF-UHFFFAOYSA-N indium tin Chemical compound [In].[Sn] RHZWSUVWRRXEJF-UHFFFAOYSA-N 0.000 claims 1
- 229910003455 mixed metal oxide Inorganic materials 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 12
- 239000002245 particle Substances 0.000 description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 150000002484 inorganic compounds Chemical class 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 2
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- PSCMQHVBLHHWTO-UHFFFAOYSA-K indium(iii) chloride Chemical compound Cl[In](Cl)Cl PSCMQHVBLHHWTO-UHFFFAOYSA-K 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910021638 Iridium(III) chloride Inorganic materials 0.000 description 1
- 229910002666 PdCl2 Inorganic materials 0.000 description 1
- 229910019032 PtCl2 Inorganic materials 0.000 description 1
- 229910021604 Rhodium(III) chloride Inorganic materials 0.000 description 1
- 229910019891 RuCl3 Inorganic materials 0.000 description 1
- 229910021627 Tin(IV) chloride Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000002173 high-resolution transmission electron microscopy Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 1
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(II) nitrate Inorganic materials [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 description 1
- YBCAZPLXEGKKFM-UHFFFAOYSA-K ruthenium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Ru+3] YBCAZPLXEGKKFM-UHFFFAOYSA-K 0.000 description 1
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(I) nitrate Inorganic materials [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- KHMOASUYFVRATF-UHFFFAOYSA-J tin(4+);tetrachloride;pentahydrate Chemical compound O.O.O.O.O.Cl[Sn](Cl)(Cl)Cl KHMOASUYFVRATF-UHFFFAOYSA-J 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G1/00—Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general
- C01G1/02—Oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/62—Platinum group metals with gallium, indium, thallium, germanium, tin or lead
- B01J23/622—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead
- B01J23/626—Platinum group metals with gallium, indium, thallium, germanium, tin or lead with germanium, tin or lead with tin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/66—Silver or gold
-
- B01J35/30—
-
- B01J35/60—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
- B01J37/0238—Impregnation, coating or precipitation via the gaseous phase-sublimation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
- B01J37/082—Decomposition and pyrolysis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/16—Reducing
- B01J37/18—Reducing with gases containing free hydrogen
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G19/00—Compounds of tin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
-
- B01J35/393—
-
- B01J35/613—
-
- B01J35/615—
-
- 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
Definitions
- the invention concerns a metal mixed oxide powder doped with a noble metal, its production and use.
- Multi-metallic powders are known from US 5984997.
- the multi-metallic powders comprise at least two elements selected from the s, p, d and/or f group of the periodic table.
- the powders can be in aggregated or agglomerated form and display an average particle size of less than 5 ⁇ m.
- the elements also include catalytically active noble metals, such as gold, platinum or palladium. They are produced by burning an emulsion containing the precursor elements of the selected compound and a flammable liquid.
- the large number of possibilities means that many substance parameters can be adjusted in this way.
- US 594997 does not disclose the form of the components in the powder, nor does it disclose the measures to be taken to influence the distribution of the components in the powder.
- the particles display catalytically active centres in accessible sites.
- the catalytically active element In flame processes, which generally lead to particles with no significant pore structure, the catalytically active element must preferably sit on the surface of the particles.
- Catalysts are generally obtained by applying a catalytically active layer from a solution with subsequent calcination.
- the disadvantage of catalysts produced in this way is often the inadequate adhesion of the catalytic layer that is applied.
- the object of the invention is to provide a noble metal- containing catalyst that displays as high as possible a number of accessible active noble metal centres, which are permanently bonded to a support, which can likewise be catalytically active.
- the invention provides an aggregated, doped metal mixed oxide powder, which is characterised in that - the BET surface area is 30 to 150 m 2 /g, - the doping component is at least one noble metal, - wherein the content of noble metal is 0.1 to 20 wt.%, ' relative to the total amount of powder, and - wherein the ratio of noble metal on the surface to the total amount of noble metal is at least 0.1.
- the ratio of the amount of noble metal on the surface of the aggregates to the total amount of noble metal can preferably be 0.1 to 0.3.
- the ratio can be determined, for example, by combined analysis of high-resolution TEM images that are representative of the sample, XPS/ESCA to determine the noble metal surface coverage and X-ray fluorescence analysis to determine the total content of noble metal .
- the content of noble metal covers a wide range from 0.1 to 20 wt.%. This means that the content of catalytically active noble metal can be specially adjusted to a particular subsequent use. The content is conventionally between 5 and 15 wt.%.
- the noble metal on the surface of the powder according to the invention can display an average diameter of 2 to 10 nm. Particularly good catalytic activity can be expected with diameters of this order of magnitude.
- the powder according to the invention can preferably contain Pt, Pd, Rh, Ru, Au or Ag as noble metal. Platinum or gold are particularly preferred.
- the powder according to the invention can preferably have a BET surface area of 30 to 150 m 2 /g and particularly preferably a BET surface area of 50 to 70 m 2 /g.
- the BET surface area is an important feature of catalytic activity and in the powder according to the invention it can be adjusted to the intended catalytic reaction.
- the metal mixed oxide powders within the meaning of the invention are ones which can be produced by oxidation from inorganic or organic precursors.
- the metal mixed oxide powders can preferably display the elements Na, K, Mg, Ca, Y, Ce, Ti, Zr, V, Nb, Mo, W, Mn, Fe, Co, Ni, Ag, Zn, Al, In, Si, Sn, Sb or Bi .
- Within an aggregate the metal oxides can be positioned alongside one another or can be in the form of true metal mixed oxides . Aggregates are understood to be three-dimensional structures of intergrown primary particles. Primary particles are the particles first formed in a flame during the oxidation reaction.
- the metal mixed oxide powders can preferably be binary oxides, in other words oxides displaying two metals. Of these, indium-tin oxide is particularly preferred.
- the content in wt.% of indium oxide, calculated as ln 2 0 3 , can preferably be 70 to 95, that of tin oxide, calculated as Sn0 2 , 1 to 10 wt.%, relative in each case to the powder according to the invention.
- a powder having indium-tin oxide as the metal oxide component can preferably display platinum or gold as the noble metal component.
- the invention also provides a process for the production of the powder according to the invention wherein a solution or dispersion containing compounds with the metal components of the oxides is atomised according to the subsequently desired ratio of oxides, in a first zone of a reactor, optionally with admixture of an inert gas stream, the atomised solution is pyrolysed in a flame consisting of hydrogen and air or oxygen-enriched air, in an area comprising the last third of the flame, the noble metal component in the form of a solution or dispersion of a noble metal compound is metered into the pyrolysis mixture at one or more points, in an amount corresponding to the subsequently desired amount of noble metal and immediately afterwards reducing gases are added in a second zone, the reducing gases being added in an amount such that a reducing atmosphere is established overall in this second zone, thereafter in a third zone
- the liquid phase of the solution or dispersion can contain water, organic solvents or mixtures thereof. Water is preferably used, in order to prevent organic constituents in the powder .
- Suitable starting substances for the metal mixed oxides can be inorganic or organic compounds, which can be converted into the oxides under the reaction conditions. As with the solvents, inorganic compounds are preferred here too for the same reasons .
- halogens can advantageously be used, chlorides being particularly advantageous .
- noble metal compounds There is a limit on the number of noble metal compounds. Here too it is in principle the case that purely inorganic compounds can preferably be used. Nevertheless, good results can also be obtained with organic noble metal compounds .
- the following compounds that can be used are cited by way of example: PtCl 2 , PtCl , H [PtCl 5 ], PdCl 2 , Pd acetate, Pd(N0 3 ) 2 , RhCl 3 , Rh(N0 3 ) 3 , RuCl 3 , IrCl 3 , H[AuCl 4 ], AgN0 3 .
- Forming gas, carbon monoxide, hydrogen, ammonia or mixtures of these gases can be used as reducing gases .
- the use of reducing gases is substantially in order to obtain powders having high catalytic activity.
- the residence time is between 0.8 and 1.5 seconds in the first zone and is between 15 seconds and 15 minutes in total in the second and third zone.
- Figure 1 shows a schematic set-up for performing the process according to the invention.
- I, II and III indicate the three reaction zones.
- Zone la describes the ' area in which the noble metal component is added.
- 1 atomised solution or dispersion of the metal compounds
- 2 oxygen-containing gas, preferably air
- 3 combustion gas, preferably hydrogen
- 4 solution or dispersion containing noble metal compound
- 5 reducing gas
- 6 waste gas
- 7 powder according to the invention.
- the solution or dispersion of the noble metal compound be fed into zone la.
- Example 1 An aqueous solution containing 88.9 g/1 of indium(III) chloride and 8.4 g/1 of tin(IV) chloride is atomised by means of compressed air and a nozzle (diameter 0.8 mm) into the reaction tube at a delivery rate of 1500 ml/h.
- An oxyhydrogen flame consisting of 5 m 3 /h of hydrogen and 15 m 3 /h of air is burning there.
- a one- percent, aqueous H [PtCl 6 ] solution is fed into the last third of this flame.
- Forming gas (5 Nm 3 /h) is introduced immediately after the addition of the solution.
- the reaction mixture passes through a residence time section of 2 m in length in 14 seconds.
- the solid is then separated from the gaseous substances using a filter and treated for a period of 15 minutes at a temperature of 250°C with a continuous supply of forming gas.
- Examples 2 to 4 are performed in the same way as Example 1.
- the feed materials and amounts used are reproduced in Table 1, the analytical data for the powders in Table 2.
- Figure 2 shows the X-ray diffraction diagram for the powder according to the invention from Example 3.
- Table 1 Feed materials and amounts used
- NM noble metal
Abstract
Aggregated, doped metal mixed oxide powder having a BET surface area of 30 to 150 m²/g, wherein the doping component is at least one noble metal and the content of noble metal is 0.1 to 20 wt.% and wherein the ratio of noble metal on the surface to the total amount of noble metal is at least 0.1. It is produced by pyrolysing compounds containing the metal component of the mixed metal oxide in a first zone in a flame consisting of hydrogen and air and metering a noble metal compound and reducing gas into the pyrolysis mixture in a second zone and separating off the solid obtained in a third zone. The mixed oxide powder doped with noble metal can be used as a catalyst.
Description
Metal mixed oxide powder containing noble metal
The invention concerns a metal mixed oxide powder doped with a noble metal, its production and use.
Multi-metallic powders are known from US 5984997. The multi-metallic powders comprise at least two elements selected from the s, p, d and/or f group of the periodic table. The powders can be in aggregated or agglomerated form and display an average particle size of less than 5 μm. The elements also include catalytically active noble metals, such as gold, platinum or palladium. They are produced by burning an emulsion containing the precursor elements of the selected compound and a flammable liquid. There are many possibilities here, such as e.g. combustion in a laminar or turbulent flame, a diffusion flame, an additionally doped or undoped flame. The large number of possibilities means that many substance parameters can be adjusted in this way.
However, US 594997 does not disclose the form of the components in the powder, nor does it disclose the measures to be taken to influence the distribution of the components in the powder.
For use as a catalyst in particular, however, it is extremely important that the particles display catalytically active centres in accessible sites. In flame processes, which generally lead to particles with no significant pore structure, the catalytically active element must preferably sit on the surface of the particles.
Catalysts are generally obtained by applying a catalytically active layer from a solution with subsequent calcination. The disadvantage of catalysts produced in
this way is often the inadequate adhesion of the catalytic layer that is applied.
The object of the invention is to provide a noble metal- containing catalyst that displays as high as possible a number of accessible active noble metal centres, which are permanently bonded to a support, which can likewise be catalytically active.
The invention provides an aggregated, doped metal mixed oxide powder, which is characterised in that - the BET surface area is 30 to 150 m2/g, - the doping component is at least one noble metal, - wherein the content of noble metal is 0.1 to 20 wt.%,' relative to the total amount of powder, and - wherein the ratio of noble metal on the surface to the total amount of noble metal is at least 0.1.
The ratio of the amount of noble metal on the surface of the aggregates to the total amount of noble metal can preferably be 0.1 to 0.3. The ratio can be determined, for example, by combined analysis of high-resolution TEM images that are representative of the sample, XPS/ESCA to determine the noble metal surface coverage and X-ray fluorescence analysis to determine the total content of noble metal .
The content of noble metal covers a wide range from 0.1 to 20 wt.%. This means that the content of catalytically active noble metal can be specially adjusted to a particular subsequent use. The content is conventionally between 5 and 15 wt.%.
The noble metal on the surface of the powder according to the invention can display an average diameter of 2 to 10 nm. Particularly good catalytic activity can be expected with diameters of this order of magnitude.
The powder according to the invention can preferably contain Pt, Pd, Rh, Ru, Au or Ag as noble metal. Platinum or gold are particularly preferred.
The powder according to the invention can preferably have a BET surface area of 30 to 150 m2/g and particularly preferably a BET surface area of 50 to 70 m2/g. The BET surface area is an important feature of catalytic activity and in the powder according to the invention it can be adjusted to the intended catalytic reaction. The metal mixed oxide powders within the meaning of the invention are ones which can be produced by oxidation from inorganic or organic precursors. The metal mixed oxide powders can preferably display the elements Na, K, Mg, Ca, Y, Ce, Ti, Zr, V, Nb, Mo, W, Mn, Fe, Co, Ni, Ag, Zn, Al, In, Si, Sn, Sb or Bi . Within an aggregate the metal oxides can be positioned alongside one another or can be in the form of true metal mixed oxides . Aggregates are understood to be three-dimensional structures of intergrown primary particles. Primary particles are the particles first formed in a flame during the oxidation reaction.
The metal mixed oxide powders can preferably be binary oxides, in other words oxides displaying two metals. Of these, indium-tin oxide is particularly preferred.
The content in wt.% of indium oxide, calculated as ln203, can preferably be 70 to 95, that of tin oxide, calculated as Sn02, 1 to 10 wt.%, relative in each case to the powder according to the invention.
A powder having indium-tin oxide as the metal oxide component can preferably display platinum or gold as the noble metal component.
Such a powder whose X-ray diffraction diagram shows the diffraction pattern of cubic indium oxide and an indium- platinum alloy or indium-gold alloy is particularly preferred.
The invention also provides a process for the production of the powder according to the invention wherein a solution or dispersion containing compounds with the metal components of the oxides is atomised according to the subsequently desired ratio of oxides, in a first zone of a reactor, optionally with admixture of an inert gas stream, the atomised solution is pyrolysed in a flame consisting of hydrogen and air or oxygen-enriched air, in an area comprising the last third of the flame, the noble metal component in the form of a solution or dispersion of a noble metal compound is metered into the pyrolysis mixture at one or more points, in an amount corresponding to the subsequently desired amount of noble metal and immediately afterwards reducing gases are added in a second zone, the reducing gases being added in an amount such that a reducing atmosphere is established overall in this second zone, thereafter in a third zone, in which a reducing atmosphere likewise prevails, the solid obtained is separated off.
The use of solutions is preferred within the meaning of the invention. Although dispersions can also be used, it has been found that the process allows the reaction to be controlled more easily if solutions are used.
The liquid phase of the solution or dispersion can contain water, organic solvents or mixtures thereof. Water is preferably used, in order to prevent organic constituents in the powder .
Suitable starting substances for the metal mixed oxides can be inorganic or organic compounds, which can be converted into the oxides under the reaction conditions.
As with the solvents, inorganic compounds are preferred here too for the same reasons .
With regard to the properties of the powders according to the invention and for cost reasons, halogens can advantageously be used, chlorides being particularly advantageous .
There is a limit on the number of noble metal compounds. Here too it is in principle the case that purely inorganic compounds can preferably be used. Nevertheless, good results can also be obtained with organic noble metal compounds . The following compounds that can be used are cited by way of example: PtCl2, PtCl , H [PtCl5], PdCl2, Pd acetate, Pd(N03)2, RhCl3, Rh(N03)3, RuCl3, IrCl3, H[AuCl4], AgN03. Forming gas, carbon monoxide, hydrogen, ammonia or mixtures of these gases can be used as reducing gases . The use of reducing gases is substantially in order to obtain powders having high catalytic activity.
It has proved to be advantageous if the residence time is between 0.8 and 1.5 seconds in the first zone and is between 15 seconds and 15 minutes in total in the second and third zone.
Figure 1 shows a schematic set-up for performing the process according to the invention. I, II and III indicate the three reaction zones. Zone la describes the' area in which the noble metal component is added. In addition: 1 = atomised solution or dispersion of the metal compounds; 2 = oxygen-containing gas, preferably air; 3 = combustion gas, preferably hydrogen; 4 = solution or dispersion containing noble metal compound; 5 = reducing gas; 6 = waste gas; 7 = powder according to the invention.
In order to be able to obtain the powder according to the invention, it is essential that the solution or dispersion of the noble metal compound be fed into
zone la. This leads to powders according to the invention wherein the noble metal component is permanently bonded to the mixed metal oxide. This can be verified by means of X- ray diffraction diagrams and XPS spectra (presence of indium-platinum bonds in XRD or strong interactions with the mixed metal oxide matrix in the XPS spectra) .
It is also essential to provide a reducing atmosphere immediately after adding the noble metal compound, in order to prevent as far as possible an undesirable oxidation of the noble metal.
Examples :
Example 1 : An aqueous solution containing 88.9 g/1 of indium(III) chloride and 8.4 g/1 of tin(IV) chloride is atomised by means of compressed air and a nozzle (diameter 0.8 mm) into the reaction tube at a delivery rate of 1500 ml/h. An oxyhydrogen flame consisting of 5 m3/h of hydrogen and 15 m3/h of air is burning there. A one- percent, aqueous H [PtCl6] solution is fed into the last third of this flame. Forming gas (5 Nm3/h) is introduced immediately after the addition of the solution.
The reaction mixture passes through a residence time section of 2 m in length in 14 seconds. The solid is then separated from the gaseous substances using a filter and treated for a period of 15 minutes at a temperature of 250°C with a continuous supply of forming gas.
Examples 2 to 4 are performed in the same way as Example 1. The feed materials and amounts used are reproduced in Table 1, the analytical data for the powders in Table 2. Figure 2 shows the X-ray diffraction diagram for the powder according to the invention from Example 3.
Table 1 : Feed materials and amounts used
Table 2 : Analytical data for the powders according to the invention
Claims
1. Aggregated, doped metal mixed oxide powder, characterised in that - the BET surface area is 30 to 150 m2/g, - the doping component is at least one noble metal, - wherein the content of noble metal is 0.1 to 20 wt.%, relative to the total amount of powder, and - wherein the ratio of noble metal on the surface to the total amount of noble metal is at least 0.1.
2. Aggregated, doped metal mixed oxide powder according to claim 1, characterised in that the ratio of the amount of noble metal on the surface of the aggregates to the total amount of noble metal is 0.1 to 0.3.
3. Aggregated, doped metal mixed oxide powder according to claims 1 or 2, characterised in that the noble metal on the surface has an average diameter of 2 to 10 nm.
4. Aggregated, doped metal mixed oxide powder according to claims 1 to 3 , characterised in that the BET surface area is 30 to 150 m2/g. 5. Aggregated, doped metal mixed oxide powder according to claims 1 to 4, characterised in that the noble metal is Pt, Pd, Rh, Ru, Au or Ag.
6. Aggregated, doped metal mixed oxide powder according to claims 1 to 5, characterised in that the metal mixed oxide powder displays the elements Na, K, Mg, Ca, Y, Ce, Ti, Zr, V, Nb, Mo, W, Mn, Fe, Co, Ni, Ag, Zn, Al, In, Si, Sn, Sb or Bi .
7. Aggregated, doped metal mixed oxide powder according to claims 1 to 6, characterised in that the metal mixed oxide powder is a binary oxide.
8. Aggregated, doped metal mixed oxide powder according to claim 7, characterised in that the binary oxide is indium-tin oxide.
9. Aggregated, doped metal mixed oxide powder according to claim 8, characterised in that the content, in wt.%, of indium oxide, calculated as ln03, is 70 to 95, that of tin oxide, calculated as Sn02, is 1 to 10. 10. ggregated, doped metal mixed oxide powder according to claims 1 to 9 , characterised in that it displays platinum or gold.
11. Aggregated, doped indium-tin mixed oxide powder according to claims 8 to 10, characterised in that an X- ray diffraction diagram shows the diffraction pattern of cubic indium oxide and an indium-platinum alloy or indium-gold alloy.
12. Process for the production of the powder according to claims 1 to 11, characterised in that - a solution or dispersion, containing compounds with the metal components of the oxides, is atomised according to the subsequently desired ratio of oxides, in a first zone of a reactor, optionally with admixture of an inert gas stream, the atomised solution is pyrolysed in a flame consisting of hydrogen and air or oxygen-enriched air, in an area comprising the last third of the flame, the noble metal component in the form of a solution or dispersion of a noble metal compound is metered into the pyrolysis mixture at one or more points, in an amount corresponding to the subsequently desired amount of noble metal and immediately afterwards reducing gases are added in a second zone, the reducing gases being added in an amount such that a reducing atmosphere is established overall in this second zone, thereafter in a third zone, in which a reducing atmosphere likewise prevails, the solid obtained is separated off.
3. Use of the powder according to claims 1 to 11 as a catalyst.
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| Application Number | Priority Date | Filing Date | Title |
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| DE102004022064.6 | 2004-05-05 | ||
| DE102004022064A DE102004022064A1 (en) | 2004-05-05 | 2004-05-05 | Noble metal-containing mixed metal oxide powder |
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| WO2005105673A1 true WO2005105673A1 (en) | 2005-11-10 |
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| PCT/EP2005/004125 WO2005105673A1 (en) | 2004-05-05 | 2005-04-19 | Metal mixed oxide powder containing noble metal |
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| DE (1) | DE102004022064A1 (en) |
| WO (1) | WO2005105673A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2399869A1 (en) * | 2010-06-25 | 2011-12-28 | Evonik Degussa GmbH | Mixed oxide powder containing the elements lithium, manganese, nickel and cobalt and method for producing same |
| EP2399867A1 (en) * | 2010-06-25 | 2011-12-28 | Evonik Degussa GmbH | Method for producing mixed oxides containing lithium |
| EP2506350A1 (en) * | 2009-11-27 | 2012-10-03 | University of Yamanashi | Oxide-based stable high-potential carrier for solid polymer fuel cell |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4238640A1 (en) * | 1991-12-06 | 1993-06-09 | Agency Of Industrial Science & Technology, Ministry Of International Trade & Industry, Tokio/Tokyo, Jp | Highly reactive metal oxide and gold catalyst for low temps. - useful for hydrogenation of carbon mono or di:oxide in synthesis of methanol |
| US20030124051A1 (en) * | 2001-06-20 | 2003-07-03 | Sabine Servaty | Indium-tin oxides |
-
2004
- 2004-05-05 DE DE102004022064A patent/DE102004022064A1/en not_active Withdrawn
-
2005
- 2005-04-19 WO PCT/EP2005/004125 patent/WO2005105673A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4238640A1 (en) * | 1991-12-06 | 1993-06-09 | Agency Of Industrial Science & Technology, Ministry Of International Trade & Industry, Tokio/Tokyo, Jp | Highly reactive metal oxide and gold catalyst for low temps. - useful for hydrogenation of carbon mono or di:oxide in synthesis of methanol |
| US20030124051A1 (en) * | 2001-06-20 | 2003-07-03 | Sabine Servaty | Indium-tin oxides |
Non-Patent Citations (1)
| Title |
|---|
| HERRMANN, J. M.; FOUJOLS, D.; FORISSIER, M.; ROSA-NUNES, M.: "Catalytic activity in propene oxidation of pure and platinum - doped tin-indium mixed perovskites", ACTAS SIMP. IBEROAM.CATAL. 9TH, vol. 2, 1984, Lisbon, pages 1573 - 1574, XP002342334 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2506350A1 (en) * | 2009-11-27 | 2012-10-03 | University of Yamanashi | Oxide-based stable high-potential carrier for solid polymer fuel cell |
| EP2506350B1 (en) * | 2009-11-27 | 2017-03-29 | University of Yamanashi | Oxide-based stable high-potential carrier for solid polymer fuel cell |
| EP2399869A1 (en) * | 2010-06-25 | 2011-12-28 | Evonik Degussa GmbH | Mixed oxide powder containing the elements lithium, manganese, nickel and cobalt and method for producing same |
| EP2399867A1 (en) * | 2010-06-25 | 2011-12-28 | Evonik Degussa GmbH | Method for producing mixed oxides containing lithium |
| WO2011160907A1 (en) * | 2010-06-25 | 2011-12-29 | Evonik Degussa Gmbh | Mixed oxide powder containing the elements lithium, manganese, nickel and cobalt and method for producing same |
| WO2011160940A1 (en) * | 2010-06-25 | 2011-12-29 | Evonik Degussa Gmbh | Method for producing mixed oxides comprising lithium |
| CN102906023A (en) * | 2010-06-25 | 2013-01-30 | 赢创德固赛有限公司 | Method for producing mixed oxides comprising lithium |
| CN102958845A (en) * | 2010-06-25 | 2013-03-06 | 赢创德固赛有限公司 | Mixed oxide powder containing the elements lithium, manganese, nickel and cobalt and method for producing same |
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| Publication number | Publication date |
|---|---|
| DE102004022064A1 (en) | 2005-11-24 |
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