Abstract: Disclosed herein is a novel hydrogen-generating, solid fuel cartridge which may be used to provide hydrogen to a proton exchange membrane (PEM) fuel cell. The cartridge contains a mixture of the hydrogen-generating solid fuel and a catalyst. The solid fuel/catalyst mixture has a packing fraction greater than about 55 percent. Throughout the fuel/catalyst mixture is means for distributing the liquid reactant; there is also a network of hydrogen-collecting, gas permeable membranes for removing the hydrogen product from the cartridge. The hydrogen-generating solid fuel cartridge may further include a liquid reactant distribution plate for distributing the liquid reactant to the solid fuel/catalyst mixture in a substantially uniform manner. The distribution plate has distribution channels arranged in a fractal pattern.