| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a colloidal solution of platinum, which does not contain a protective agent, hardly causes coagulation or precipitation even if the concentration is high, and shows superior long-period stability. <P>SOLUTION: The colloidal solution of platinum comprises a platinum colloid comprising platinum particles and a solvent of water or a mixture solvent including water and an organic solvent, and does not contain the protective agent, wherein the platinum content in the colloidal solution of platinum is 300 to 20,000 ppm, the pH is 5.0 to 12.0 and the electrical conductivity is 100 mS/m or less. The colloidal solution of platinum can be produced by reducing platinum ions in a platinum salt solution to form the platinum particles, but the production process needs to include the steps of: adjusting the pH of and the concentration of dissolved oxygen in the platinum salt solution before the reduction step; and ultrafiltrating the colloidal solution of platinum obtained after the reduction step to adjust the electrical conductivity and the pH. <P>COPYRIGHT: (C)2010,JPO&INPIT |
