US Patent 7855160 Catalyst ink

A catalyst ink is provided, comprising: 25-95% by weight water; 1-50% by weight of at least one solid catalyst, typically a highly dispersed platinum catalyst; 1-50% by weight of at least one polymer electrolyte in acid (H+) form; and 1-50% by weight of at least one polar aprotic organic solvent. The catalyst ink typically has a viscosity at 1 sec−1 of 10 Pa·sec or less. The catalyst ink typically does not ignite spontaneously when dried to completion in air at a temperature of 80° C. or greater. The catalyst ink may be used in the fabrication of membrane electrode assemblies for use in fuel cells.