Abstract: The manufacture of hydrogen and oxygen by the dissociation of water vapor at elevated temperatures followed by separation of hydrogen from the water vapor and the oxygen produced using a hydrogen permeable membrane is improved by increasing the surface area of the membrane exposed to the dissociation gas mixture.One way of increasing the surface area of contact, according to the present invention, is to form a hydrogen permeable membrane coated on one side of a porous refractory wafer with an inlet hole through the wafer connecting a beginning of the maze and an outlet at the end of the maze facing the opposite direction from the inlet. A number of these wafers are then stacked or replicated front-to-back with each outlet corresponding to the inlet of the next wafer to give a compact and efficient hydrogen diffusion separator.