NOVELTY - An article formed as a fuel cell gas diffusion article (200) comprises a substrate (210) having a surface; and a porous layer (220) supported by the surface of the substrate. The porous layer comprises electrically conductive particles and a polymer; and has a thickness of at most 30 microns.    USE - As a fuel cell gas diffusion article (claimed).    ADVANTAGE - The fuel cell gas diffusion article with porous layer including nanotubes improves deposition and adhesion of the polymer in the porous layer on the substrate supporting the layer, reduces permeating of the porous layer into the substrate, and offers flexibility in altering air permeability of the porous layer. The method performed continuously, thus reduces costs for producing membrane electrode assemblies and fuel cells; performed at an ambient temperature (e.g. 25 - 50degreesC), thus avoiding the equipment and costs associated with a high temperature sintering process; and results in a crack-free porous layer whose pore size and density is readily adjusted, such as the pores have an average pore diameter of at most 30 (preferably at least 0.1) microns.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (a) preparation of the fuel cell gas diffusion article involving applying a mixture onto a surface of a substrate to form a layer, and removing the first solvent by contacting the layer with a second solvent miscible with the first solvent. The mixture comprises electrically conductive particles and a polymer (at most 10 wt.%) in a first solvent. The second solvent is a non-solvent to the polymer;    (b) a membrane electrode assembly comprising a first gas diffusion article including the substrate, and the porous layer supported by the surface of the substrate; a second gas diffusion article; first and second catalyst layers between the first and second gas diffusion articles; and a solid electrolyte between the first and second catalyst layers; and    (c) a fuel cell comprising the membrane electrode assembly.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of a fuel cell gas diffusion article.    fuel cell gas diffusion article (200)    substrate (210)    porous layer. (220)