METHOD FOR PREPARING PRECIOUS METAL ISOLATED ATOMS IN SOLUTION, AND APPLICATIONS THEREOF

Abstract

A method for the preparation of isolated noble metal atoms in a solution comprises mixing a protective agent, a precious metal compound, and a reducing agent thoroughly. At certain temperature, isolated noble metal atoms are formed after reaction, thereby leading to isolated noble metal atoms which are stable in the solution. Isolated noble metal atoms on solid material surface can be prepared by impregnating a noble metal atom solution onto a solid medium. Alloys and catalysts etc. can be prepared by using the single atoms solution as raw material. The invention achieves, for the first time, the preparation of reduced single atoms in a solution phase. Formation of metal nanoparticles is avoided compared to the conventional synthesis of metal materials in solution phase. Compared with solid surface supported monoatomic materials, this invention allows for the preparation of materials that are characterized by high metal loading and high stability.

Claims

1. A method of preparing isolated noble metal single atoms in solution, comprising mixing a protective agent, a noble metal compound precursor, a reducing agent, and a solvent to carry out a reaction and obtain the isolated noble single atoms in solution.

2. The method of claim 1 wherein the isolated noble metal atoms are platinum group elements or post platinum group elements; the platinum group elements are selected from the group consisting of palladium, rhodium, ruthenium, iridium, ruthenium, and platinum; the post platinum group elements are silver or gold.

3. The method of claim 1 wherein said noble metal compound precursor is a platinum compound precursor, a palladium compound precursor, a rhodium compound precursor, an iridium compound precursor, a ruthenium compound precursor, an osmium compound precursor, a gold compound precursor, or a silver compound precursor.

4. The method of claim 3 wherein said platinum compound precursor is selected from the group consisting of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, platinite chloride, platinum chloride, diethylamine chloride platinum, platinum nitrate, 1, 5-cyclooctadiene dichloride platinum, trichloride (ethylene) potassium platinate, dichloro-tetramine platinum, dinitrile phenyl dichloroplatin, dichloroplatin (triphenyl phosphite) dichloroplatin, and ammonium tetrachloroplatinate.

5. The method of claim 3 wherein said palladium compound precursor is selected from the group consisting of palladium chloride, palladium nitrate, tetrachloroplatinate, palladium(2+) tetraammine-dichloride, trans-dichlorodiammine palladium (II), palladium(II) acetate, palladium(II) sulfate, palladium(II) trifluoroacetate, palladium(II) acetylacetonate, potassium hexachloropalladate(IV), ammonium hexachloropalladate(IV), palladium tetraammonia (II) acetic acid, sodium tetrachloropalladate(II), potassium tetrachloropalladate(II), ammonium tetrachloropalladate(II), potassium tetracyanopalladate(II) hydrate, potassium tetrabromopalladate(II), palladium pivalate, palladium(II) cyanide, palladium(II) bromide, palladium thiosulfate(II), palladium(II) iodide, sulfonated palladium(II), (1,3-bis(diphenylphosphino)propane)palladium(II) chloride, dichloro(1,5-cyclooctadiene)palladium(II), (2,2′-bipyridine) dichloropalladium(II), [1,2-bis(diphenylphosphino)ethane]dichloropalladium(II), 1,4-bis(diphenylphosphino)butane-palladium(II) chloride, and (ethylenediamine) palladium(II) chloride.

6. The method of claim 3 wherein said rhodium compound precursor is selected from the group consisting of rhodium (III) nitrate, acetyl acetone rhodium (III), Di-μ-chlorotetraethylene dirhodium(I), sodium hexachlororhodate(III), potassium hexachlororhodate(III), ammonium hexachlororhodate(III), rhodium chloride (III), tris(triphenylphosphine)rhodium(I) chloride, trichlorotris(ethylenediamine)rhodium(III), bis(ethylene) rhodium(I) acetylacetonate(I), (acetylacetonato)dicarbonylrhodium(I), dicarbonyl (pentamethylcyclopentadienyl) rhodium(I), and bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate.

7. The method of claim 3 said iridium compound precursor is one of hydrogen hexachloroiridate(IV),iridium(III) acetylacetonate, sodium hexachloroiridate(III), potassium hexachloroiridate(III), ammonium hexachloroiridate(IV), potassium hexanitroiridate(III), iridium(III) chloride, iridium(III) bromide, (acetylacetonato) (1,5-cyclooctadiene)iridium(I), (1,5-cyclooctadiene) (hexafluoroacetylacetonato) iridium(I), pentaamminechloroiridium(III) chloride, dichlorotetrakis (2-(2-pyridinyl) phenyl) diiridium(III), (acetylacetonato) dicarbonyliridium(I), bis(1,5-cyclooctadiene) iridium(I) tetrafluoroborate, (1,5-cyclooctadiene) (pyridine) (tricyclohexylphosphine)-iridium(I) hexafluorophosphate, and bis[1,2-bis(diphenylphosphino)ethane]carbonylchloroiridium(I).

8. The method of claim 3 wherein the ruthenium compound precursor is selected from the group consisting of ruthenium(III) chloride, ruthenium(III) acetylacetonate, ruthenium(III) nitrosyl nitrate solution, hexaammineruthenium(II) chloride, ammonium hexacyanoruthenate(II), potassium hexacyanoruthenate(II), tetrapropylammonium perruthenate, ethylenediaminetetraacetic acid ruthenium(III) chloride, potassium aquapentachlororuthenate(III), ruthenium(III) iodide hydrate, tris(triphenylphosphine) ruthenium(II) dichloride, hexaammineruthenium(III) chloride, dichlorotetrakis (triphenylphosphine)ruthenium(II), dichloro[(2,6,10-dodecatriene)-1,12-diyl] ruthenium(IV), dichlorotris(1,10-phenanthroline)ruthenium(II), bis(triphenylphosphine) ruthenium(II) dicarbonyl chloride, and pentaamminechlororuthenium(III) chloride.

9. The method of claim 3 wherein said osmium compound precursor is selected from the group consisting of potassium osmate (VI) dihydrate, potassium hexachloroosmate (IV), ammonium hexachloroosmate (IV), bis(pentamethylcyclopentadienyl)osmium (II), osmium (III) chloride, and pentaammine (trifluoromethanesulfonato)osmium (III) triflate.

10. The method of claim 3 wherein the gold compound precursor is selected from the group consisting of potassium gold(III) chloride, sodium dicyanoaurate(I), gold (I) chloride, Chloro(dimethylsulfide)gold (I), gold (III) oxide, trichloro(pyridine)gold (III), gold (III) chloride, sodium tetrachloroaurate (III), gold (III) chloride, ammonium tetrachloroaurate(III), gold(I) cyanide, chlorocarbonylgold(I), gold(III) bromide, gold(I) iodide, and chloro (triphenylphosphine)gold (I).

11. The method of claim 3 wherein the silver compound precursor is selected from the group consisting of silver nitrate, silver lactate, silver citrate, silver chlorate, silver cyanate, silver bromate, silver acetate, silver trifluoroacetate, silver acetylacetonate, potassium dicyanoargentate, silver pentafluoropropionate, silver cyanide, and silver benzoate.

12. The method of claim 3 wherein the reducing agent is is selected from the group consisting of alcohol compounds, glucose, formic acid, citric acid, tartaric acid, ascorbic acid, hydrazine hydrate, borohydride, and hydrogen.

13. (canceled)

14. The method claim 1 wherein the protective agent is a block copolymer containing siloxane groups and hydrophilic polymers.

15. The method of claim 1 wherein the protective agent is a block copolymer containing siloxane groups and polyether groups.

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)

21. (canceled)

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32. The method of claim 1, wherein the molar ratio of the amount of the reducing agent to the noble metal compound precursor is from 1 to 10.sup.7:1.

33. The method of claim 1, wherein the molar ratio of the amount of the reducing agent to the solvent is 1:10.sup.5-30:1.

34. (canceled)

35. The method of claim 1, wherein the range of the reaction temperature is from −70 to 200° C.

36. The method of claim 1, the range of reaction time is from 0.5 to 200 hours.

37. A method of preparing an isolated noble metal atoms-solid medium material, comprising: 1) impregnation: fully mixing and impregnating a solid medium with isolated noble single atoms solution; and 2) removing reductant and solvent: vacuum under reduced pressure at −30 to 200° C. to remove the reductant and solvent from the isolated noble metal atoms solution.

38. The method of claim 37, wherein the loading amount of the isolated noble metal atoms on the isolated noble metal atoms-solid medium material is from 0.01 to 50%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1. UV-visible spectra of examples 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.

[0047] FIG. 2. UV-visible spectra of example 2.

[0048] FIG. 3. UV-visible spectra of example 3.

[0049] FIG. 4. Infrared spectrum of CO adsorption on 1 wt % Pt single atom/Al2O3 (example 19).

[0050] FIG. 5. Infrared spectrum of CO adsorption on 0.01 wt % Pt single atom/Al2O3 (example 20).

[0051] FIG. 6. Infrared spectrum of CO adsorption on 50 wt % Pt single atom/Al2O3 (example 21).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0052] The invention will be further described in detail below by taking the synthesis of noble metal platinum monoatoms as an example. The protection of the patent is not limited to the specific embodiments but is limited by the claims.

EXAMPLE 1

[0053] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 ml ethanol, 10.2 ml water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced. (Note: The ultraviolet absorption peak at 265 nm represents the absorption peak of PtC162-, and the disappearance of the ultraviolet absorption peak indicates that chloroplatinic acid is completely reduced.)

EXAMPLE 2

[0054] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 ml ethanol, 10.2 ml water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 200° C. for 30 min. The UV-visible absorption spectrum (FIG. 2) shows that chloroplatinic acid is completely reduced.

EXAMPLE 3

[0055] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 ml ethanol, 10.2 ml water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at −70° C. for 200 h. The UV-visible absorption spectrum (FIG. 3) shows that chloroplatinic acid is completely reduced.

EXAMPLE 4

[0056] Preparation of isolated platinum atoms in solution: 0.0344 g polyethylene glycol-polysiloxane block copolymer, 135 ml ethanol, 10.2 ml water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L (the ratio of Pt single atom to protective reagent is 50 wt %) are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 5

[0057] Preparation of isolated platinum atoms in solution: 1719.92 g polyethylene glycol-polysiloxane block copolymer, 1000 ml ethanol, 100 ml water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L (the ratio of Pt single atom to protective reagent is 0.001 wt %) are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 6

[0058] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 4.05 mg ethanol (the ratio of ethanol to H2PtC16 is 1:1 mol/mol), 145 mL water (the ratio of ethanol to water is 1:105 mol/mol) and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 7

[0059] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 882 g ethanol (1.14L, the ratio of ethanol to H2PtC16 is 107:1 mol/mol), 100.2 mL water and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 8

[0060] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 148.5 mL ethanol, 1.02 mL water (the ratio of ethanol to water is 30:1 mol/mol) and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 9

[0061] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL toluene and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 10

[0062] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL hexane and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 11

[0063] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL cyclooctane and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 12

[0064] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL chlorobutane and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 13

[0065] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL n-butanol and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 14

[0066] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL dipropyl ether and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 15

[0067] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL 2-hexanone and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 16

[0068] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL butyraldehyde and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 17

[0069] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL propionic acid and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 18

[0070] Preparation of isolated platinum atoms in solution: 0.6465 g polyethylene glycol-polysiloxane block copolymer, 135 mL ethanol, 10.2 mL propiononitrile and 4.8 ml chloroplatinic acid solution with a concentration of 0.018404 mol/L are thoroughly mixed, and then the temperature is raised. The chloroplatinic acid is completely reduced under reflux condensation at 105° C. for 3 hours. The UV-visible absorption spectrum (FIG. 1) shows that chloroplatinic acid is completely reduced.

EXAMPLE 19

[0071] Preparation of Al.sub.2O.sub.3 supported platinum single atom: 1 g γ-Al2O3 was added to 87 ml Pt singe atom solution from example 1. The support is impregnated for 1 h. Ethanol and water were removed at 40° C. under vacuum, and the 1 wt % Pt single atom/γ-Al.sub.2O.sub.3 is obtained. The infrared spectrum of CO adsorption on 1 wt % Pt single atom/γ-Al.sub.2O.sub.3 identifies the success of the material preparation. (explanation: peak between 1800 and 1900 cm-1 is attributed to bridged CO on Pt, and the peak at 2086 cm-1 is attributed to linear adsorption of CO on Pt. Peak between 1800 and 1900 cm-1 is not observed in FIG. 4, which identifies the absence of Pt particles or clusters containing two or more Pt atom. With the increase of CO pressure, there is no blue shift at the peak position at 2086 cm.sup.−1, which indicates that platinum exists in the form of single atoms. Based on above, the new material (1 wt %Pt single atom/γ-Al.sub.2O.sub.3) is successfully synthesized.)

EXAMPLE 20

[0072] Preparation of Al.sub.2O.sub.3 supported platinum single atom: 100 g γ-Al.sub.2O.sub.3 was added to 87 ml Pt singe atom solution from example 1. The support is impregnated for 1 h. Ethanol and water were removed at 40° C. under vacuum, and the 0.01 wt % Pt single atom/γ-Al.sub.2O.sub.3 is obtained. The infrared spectrum of CO adsorption on 0.01 wt %Pt single atom/γ-Al.sub.2O.sub.3 shows in FIG. 5.

EXAMPLE 21

[0073] Preparation of Al2O3 supported platinum single atom: 0.1 g γ-Al.sub.2O.sub.3 was added to 87 ml Pt singe atom solution from example 1. The support is impregnated for 1 h. Ethanol and water were removed at 40° C. under vacuum, and the 0.01 wt % Pt single atom/γ-Al.sub.2O.sub.3 is obtained. The infrared spectrum of CO adsorption on 10 wt % Pt single atom/ Al2O3 shows in FIG. 6.