Liquid suspension of particles of a metal belonging to the platinum group and a method for the manufacture of such a suspension

• US 4,425,261 A
• Filed: 11/05/1981
• Issued: 01/10/1984
• Est. Priority Date: 03/24/1980
• Status: Expired due to Fees

• Current Assignee: Ytkemiska Institutet Box
• Original Assignee: Ytkemiska Institutet
• Inventors: Boutonnet, Magali, Stenius, Per, Kizling, Jerzy
• Primary Examiner(s): Shine, W. J.
• Application Number:
  US06/320,967
• Time in Patent Office: 796 Days
• Field of Search: 252/466 PT, 252/472, 252/313 R, 106/1.05, 106/1.11, 106/1.21
• US Class Current: 502/339
• CPC Class Codes: B01J 23/40 of the platinum group metals
• CPC Class Codes: B01J 23/628 with lead
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/45 Nanoparticles
• CPC Class Codes: C22B 11/00 Obtaining noble metals

Abstract

A stable suspension of particles of a metal belonging to the platinum group consists of a microemulsion in which the particles are suspended. The suspension is prepared by dissolving a metal salt in a microemulsion, and reducing the salt to form a metal.

Claims

1. A liquid suspension of particles of a metal belonging to the platinum group, characterized in that the liquid comprises a microemulsion and that the size of the metal particles does not deviate from the average by more than about 10%.

2. A suspension as claimed in claim 1, characterized in that the microemulsion comprises a hydrocarbon, a non-ionic surfactant, and water.

3. A suspension as claimed in claim 1, characterized in that the metal particles have a size of 2-5 nm.

4. A suspension as claimed in claim 1, characterized in that the metal particles each comprise a single crystal.

5. A suspension as claimed in claim 1, in which the microemulsion comprises n-hexane, pentaethyleneglycol dodecylether, and water, characterized in that the composition of the microemulsion is represented by the shaded area in any of the ternary diagrams disclosed in the drawing.

10. A process for preparing a catalyst using the suspension of particles of claim 1, comprising the steps of (1) wetting a carrier with the suspension of particles comprising the microemulsion, and then (2) evaporating the liquid so as to deposit the particles on the carrier.

6. A method for the manufacture of a liquid suspension of particles of a metal belonging to the platinum group by reducing a metal salt in an aqueous solution, characterized in dissolving the metal salt in a microemulsion, and reducing the dissolved metal salt to the metallic state to thereby provide metal particles of a size which does not deviate from the average by more than about 10%.

7. A method as claimed in claim 6, characterized in dissolving the metal salt in a microemulsion comprising a hydrocarbon, a non-ionic surfactant, and water.

8. A method as claimed in claim 6, characterized in reducing the metal salt with hydrogen or hydrazine.

9. A method as claimed in claim 6, in which acid by-products are formed in the reaction, characterized in giving the microemulsion, before the reduction, such as increased pH that the pH after the reduction is at least 4.