TECHNOLOGY FOCUS - METALLURGY - Preferred Material: The catalyst material is from supported catalysts comprising finely divided, electrically conductive carbon black and, as catalytically active components, elements of the platinum group (i.e. platinum, palladium, silver, gold, ruthenium, rhodium, osmium, iridium), and/or their alloys.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The organic solvent is from the class of tertiary alcohols of formula R1(R2)C(OH)(R3), and/or from the class of aliphatic diketones.R1, R3=Me, Et, propyl, isopropyl, butyl, isobutyl, tert-butyl, CH3(CH3)C(OH)-, CH3(CH3)C(OH)-CH2-, CH3(CH3)C(OH)-CH2-CH2-, CH3-O-, C2H5-O-, C3H7-O-, phenyl-O-, benzyl-O-, CH3-O-CH2-, C2H5-O-CH2-, C3H7-O-CH2-, CH3-CH(CH3)-O-CH2-, phenyl-O-CH2-, benzyl-O-CH2-, CH3(C=O)-CH2-, CH3(C=O)-CH2-CH2-, CH3-CH2(C=O)-CH2-CH3-O(C=O)-CH2-, CH3CH2-O(C=O)-CH2-, HSO3-, HSO3-CH2-, HSO3-CH2-CH2-;andR2=Me, Et, propyl, isopropyl, butyl, isobutyl, -CH2-O-CH3.Preferred Composition: The ink comprises (wt.%): organic solvent (1-90, preferably 10-50) and water (1-50, preferably 5-25). The ionomer material is used in an aqueous solution or dispersion having an ionomer content of 5-30 wt.% (based on the total weight of the solution or dispersion). Preferred Component: The organic solvent is completely miscible with water.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The ionomer material comprises a tetrafluoroethylene-fluorovinyl ether copolymer bearing acid functions, particularly sulfonic acid groups. The ink contains additives such as wetting agents, antifoaming agents, surfactants, anti-settling agents, preservatives, pore formers, leveling agents, stabilizers, pH modifiers, sodium hydroxide, or potassium hydroxide. SPECIFIC COMPOUNDS - The organic solvent is tert-butanol, 2-methyl-2-butanol, 2-methyl-2-pentanol, 2,3-dimethyl-2-butanol, 2,3-dimethyl-2,3-butanediol, 2,4-dimethyl-2,4-pentanediol, 2,4-dimethyl-2,4-hexanediol, 2,5-dimethylhexane-2,5-diol, 3-hydroxy-3-methyl-2-butanone, and/or 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol). It is 2,3-butanedione (diacetyl), 2,3-pentanedione (ethylmethylglyoxal), 2,4-pentanedione (acetylacetone), 2,3-hexanedione, 2,4-hexanedione, 3,4-hexanedione, 2,5-hexanedione, 2,6-heptanedione, 3-methyl-2,5-hexanedione, and/or 3-ethyl-2,5-hexanedione.