The present invention discloses a method for preparing platinum (Pt) based nano-size catalyst which is useful as an electrode catalyst of a direct methanol fuel cell (DMFC). This method includes the implementation of a reduction reaction of a platinum precursor and an optional ad-metal precursor with a reducing agent in a solvent and in the presence of a stabilizer to form a suspension containing colloidal particles of platinum or platinum/ad-metal; mixing the suspension with a co-solvent; subjecting the resultant mixture to a centrifugal treatment to form a platinum or platinum/ad-metal colloidal particle portion and a liquid portion, repeating the co-solvent mixing and centrifugal treatment to the platinum or platinum/ad-metal colloidal particle portion until the resultant liquid portion no longer contains the product of the reduction reaction; and drying the resultant platinum or platinum/ad-metal colloidal particle portion to obtain a platinum based nano-size catalyst.
Description
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows the photograph of platinum black catalyst prepared in Example 2 of the present invention, which is taken under a transmission electronic microscope (TEM).
Claims
1. A method for preparing a platinum based nano-size catalyst comprising the following steps:
a) carrying out a reduction reaction of a platinum precursor and an optional ad-metal precursor with a reducing agent in a solvent and in the presence of a stabilizer, in order to form a suspension containing colloidal particles of platinum or platinum/ad-metal;b) mixing the resulting suspension with a co-solvent;c) subjecting the resulting mixture to centrifugal treatment, thereby giving rise to platinum or platinum/ad-metal colloidal particle portion and a liquid portion;d) repeating the co-solvent mixing and centrifugal treatment to the platinum or platinum/ad-metal colloidal particle portion, until the resulting liquid portion substantially does not contain a product of the reduction reaction; ande) drying the platinum or platinum/ad-metal colloidal particle portion to obtain a platinum based nano-size catalyst.
2. The method of claim 1, wherein the co-solvent used in step b) is acetone, C3-C12 aliphatic alkane or toluene.
3. The method of claim 2, wherein the C3-C12 aliphatic alkane is pentane.
4. The method of claim 1, wherein the solvent, reducing agent, and stabilizer used in step a) is ethylene glycol.
5. The method of claim 2, wherein the solvent, reducing agent, and stabilizer used in step a) is ethylene glycol.
6. The method of claim 3, wherein the solvent, reducing agent, and stabilizer used in step a) is ethylene glycol.
7. The methods of claim 1, wherein in step a), the solvent is a mixed solution of H2O and ethanol, the reducing agent is ethanol, and the stabilizer is polyvinyl pyrrolidone (PVP).
8. The methods of claim 2, wherein in step a), the solvent is a mixed solution of H2O and ethanol, the reducing agent is ethanol, and the stabilizer is polyvinyl pyrrolidone (PVP).
9. The methods of claim 3, wherein in step a), the solvent is a mixed solvent of H2O and ethanol, the reducing agent is ethanol, and the stabilizer is polyvinyl pyrrolidone (PVP).
10. The method of claim 4, wherein the platinum precursor used in step a) is chloroplatinic acid (H2PtCl6), and the product of the reduction reaction in step d) is chloride ions.
11. The method of claim 7, wherein the platinum precursor used in step a) is chloroplatinic acid (H2PtCl6), and the product of the reduction reaction in step d) is chloride ions.
12. The method of claim 10, in which the liquid portion in step d) contains less than 300 ppm of chloride ions.
13. The method of claim 11, in which the liquid portion in step d) contains less than 300 ppm of chloride ions.
14. The method of claim 1, wherein the platinum precursor used in step a) is chloroplatinic acid (H2PtCl6), bis(acetylacetonato) platinum (II), dinitrodiaminoplatinum (II) (Pt(NH3)2(NO2)2), or tetraaminoplatinum (II).
15. The method of claim 1, wherein the solvent used in step a) is ethylene glycol or a mixed solvent of H2O and alcohol.
16. The method of claim 1, wherein the reducing agent used in step a) is ethanol, ethylene glycol, sodium borohydride, hydrazines, or formaldehyde.
17. The method of claim 1, wherein the stabilizer used in step a) is polyvinyl pyrrolidone (PVP), polyol, polyvinyl alcohol, or sodium bis(2-ethylhexyl) sulfosuccinate (AOT).
Patent Application
20070149396
