PLATINUM AND PLATINUM ALLOY POWDERS WITH HIGH SURFACE AREAS AND LOW CHLORINE CONTENT AND PROCESSES FOR PREPARING THESE POWDERS

摘要

Platinum or platinum alloy powder for use as a catalyst in fuel cells or chemical reactions combines a BET specific surface area above 40m2/g with a chlorine content below 100ppm. An Independent claim is also included for the production of the powder involving: (i) heating a melt of a low-melting mixture of alkali nitrates, a low-chlorine platinum (Pt) compound and optionally a low-chlorine compound of the alloying element to decompose the latter 2 compounds to their oxides; (ii) cooling the melt and dissolving it in water; and (iii) reducing the (mixed) oxides to the corresponding metal(s).