| 摘要 |
The invention provides platinum or platinum alloy powders for use in fuel cells and for chemical reactions. The powders are characterized by a high surface area and, at the same time, low chlorine contents. The powders are prepared by forming a melt which contains, as starting substances, a low melting mixture of alkali metal nitrates, a chlorine-free platinum compound and optionally chlorine-free compounds of alloying elements, the melt is then heated to a reaction temperature at which the platinum compound and the compounds of alloying elements thermally decompose to give oxides, the melt is then cooled and dissolved in water and the oxides or mixed oxides formed are converted into platinum or platinum alloy powders by subsequent reduction. Binary or ternary eutectic mixtures from the LiNO3-KNO3-NaNO3 system are suitable as a low melting mixture of nitrates of the alkali metals. Hexahydroxoplatinic-(IV)-acid is preferably used as a chlorine-free platinum compound.
|
