NOVELTY - A diffusion layer for a direct oxidation fuel cell having a protonically conductive membrane, comprises a substrate comprising carbon and coated with an electrically conductive layer that forms a microporous layer. The microporous layer has indented channels that provide preferential flow paths to cause liquids to travel in predetermined directions in the fuel cell.    USE - For a direct oxidation fuel cell having a protonically conductive membrane.    ADVANTAGE - The inventive diffusion layer provides optimal gas diffusion properties, and resists flooding of the cathode portion of the fuel cell. It helps maintains overall water balance in the fuel cell system.    DETAILED DESCRIPTION - A diffusion layer for a direct oxidation fuel cell having a protonically conductive membrane, comprises a substrate comprising substantially of carbon and being coated with an electrically conductive layer that forms a microporous layer on the substrate. The microporous layer has indented channels formed in it, providing preferential flow paths to cause liquids to travel in predetermined directions in the fuel cell.    INDEPENDENT CLAIMS are also included for:    (a) a membrane electrode assembly (6), comprising a protonically conductive, electronically non-conductive membrane (7); diffusion layer(s) as above; and a catalyst disposed on the membrane and the catalyst forming an active area of the assembly;    (b) a direct oxidation fuel cell (3), comprising a membrane electrode assembly as above; an anodic diffusion layer disposed in intimate contact with the anode face (9) of the membrane electrode assembly that allows the associated fuel mixture to pass through to the anode face as fuel is consumed at the anode, and which also allows anodically-generated carbon dioxide to be transported away from the anode face of the membrane; a cathodic diffusion layer disposed in intimate contact with the cathode face of the membrane electrode assembly that allows oxygen to pass through to the cathode face of the membrane electrode assembly, the cathode diffusion layer (10) comprises a carbon containing substrate and a microporous layer having channels formed in it to provide preferential flow paths such that liquid reactions and byproducts in the fuel cell travel in predetermined directions along the channels; and a mechanism for collecting electric current generated in the electricity-generating reactions to provide the electric current to a load;    (c) a direct oxidation fuel cell system (2), comprising a direct oxidation fuel cell as above; a fuel source; a fuel container and delivery assembly coupled between the fuel source and the direct oxidation cell; mechanism for removing reactants from the fuel cell; a mechanism for removing byproducts from the membrane electrode assembly; electrical coupling mechanism for connecting the fuel cell with an external device to which it is providing power;    (d) a method of fabricating a liquid removing diffusion layer for a protonically conductive membrane used in direct oxidation fuel cell, comprising providing a substrate substantially of carbon; treating the substrate by coating it with a microporous layer of material that is electrically conductive, hydrophobic and permeable to gases; and forming, in the microporous layer, channels, producing preferential flow paths to direct liquids in predetermined directions in the fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of a direct oxidation fuel cell system with which the diffusion layer may be used.    Direct oxidation fuel cell system (2)    Direct oxidation fuel cell (3)    Membrane electrode assembly (6)    Protonically conductive, electronically non-conductive membrane (7)    Anode face (9)    Cathode diffusion layer (10)