Control of the interaction of novel platinum-on-carbon electrocatalysts with fluorinated hydrocarbon resins in the preparation of fuel cell electrodes

Claim 1

In the method of producing reproducibly a fuel cell electrode comprising a substantially uniform mixture of a finely divided 15 A-25 A platinum-on-carbon electrocatalyst comprising platinum particles substantially all in the range of 15 A- 25 A in size, and finely divided fluorinated hydrocarbon resin, the steps of forming an aqueous suspension of the said electrocatalyst with a sufficiently water-soluble ionizable salt of a polyvalent metallic cation in an amount between 10 -3 and 10 -6 gram-moles of salt per liter of suspension and mixing therewith an aqueous colloidal dispersion of said resin, rapidly to coagulate the mix without substantially affecting the finely divided 15 A-25 A platinum-on-carbon electrocatalyst performance, thereby causing said colloidal resin to flocculate substantially completely and at a controlled rapid rate and in substantially uniform admixture with said electrocatalyst in less than five minutes.