TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Method: The catalytic fluid is dried after dispensing the fluid on the first side of the substrate. It is prepared by preparing a mixture of 30-250 g solvent and 130-200 g water, and preparing a solution of 5-30 g ionomer and 5-20 g platinum supported on a high surface area carbon in the mixture of solvent and water. It supports hydrogen oxidation or oxygen reduction. The catalytic coating is dispensed so that it has a uniform thickness across the first side of the substrate. It increases the probability of ionization of a hydrogen-based fuel or a reaction of a hydrogen ion with oxygen. The direct writing instrument is configured so that the width and thickness of a line (169) forming the pattern depends upon the diameter of the direct writing instrument from which the catalytic fluid is dispensed and the volumetric flow rate of the fluid. The line thickness is determined by t=Q/(Vw). The catalytic coating forms a conductive layer on the first side of the substrate. A second fluid comprising noncatalytic fluid or precious metal is dispensed on the first side of the substrate. The coating is formed on a diffusion media comprising carbon fiber and/or carbon cloth.Q = volumetric flow rate of the fluid;V = writing speed of the instrument;w = line width.Preferred Composition: The catalytic fluid comprises 4 wt.% platinum, 4 wt.% ionomer, 4 wt.% carbon, 28 wt.% water, and 60 wt.% solvent. It exhibits a perfluorinated polymer to carbon ratio of 0.8-2. It comprises 8-20%, preferably 12% solids.Preferred Property: The catalytic fluid exhibits a viscosity of 70-2000, preferably 300 Cp.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The ionomer is perfluorinated polymer. The substrate is electrolyte material, polytetrafluoroethylene sheet, or a gas diffusion media. The electrolyte material comprises a proton conducting membrane. The intermediate material is polytetrafluoroethylene or ethylene tetrafluoroethylene.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The solvent comprises isopropyl alcohol. The electrolyte material comprises perfluorinated sulfonic acid.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The noncatalytic fluid comprises a carbonaceous material comprising carbon black and/or graphite.