A fuel cell diffusion layer for delivering a fuel mixture to the anode face of a catalyzed membrane and for resisting flow of carbon dioxide produced in the anodic reaction back into the associated fuel chamber. The diffusion layer contains either conduits or channels on one aspect thereof to redirect the carbon dioxide generated at the anode in the fuel cell reaction away from the catalyzed membrane and away from the fuel chamber. This avoids the volume replacement by carbon dioxide of fuel mixture in the anode chamber and enhances the concentration of methanol that can be used in the fuel mixture. It also serves to allow only that fuel that is consumed in the reaction to enter the space between the anode face of the catalyzed membrane and the diffusion layer adjacent thereto. The diffusion layer further includes perforations to increase the ability to deliver fuel to the anode aspect of the membrane electrode assembly of the fuel cell. In accordance with another aspect of the invention, the perforations can comprise Nafion-filled capillaries.