TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: Lithium, magnesium, sodium, potassium, calcium and aluminum are disposed in at least one hole of the substrate. Heat treatment is performed at about 500-1000degreesC. At least one reactant is disposed in the substrate and forms a binary couple or ternary triple, upon heat treatment. Heat treatment of the substrate is performed in nitrogen atmosphere. The method further involves (i) identifying and analyzing at least one phase of the diffusion couple using electron microscope analysis, (ii) slicing and grinding the diffusion multiple, or (iii) analyzing the diffusion multiple by electron microprobe analysis or electron backscatter diffraction. Slicing and grinding of the diffusion multiple is conducted after the heat treatment. Determination of the suitability of at least one phase for the adsorption of hydrogen is conducted by time of flight secondary mass ion spectrometry, thermal imaging or by using a tungsten oxide detector. Heating is performed using microwave radiation, convectional heating and/or electrical resistive heating. Heating is effected by the heat from the exhaust of a fuel cell.Preferred Dopant: The method involves further adding a dopant comprising titanium, vanadium, zirconium, yttrium, lanthanum, nickel, manganese, cobalt, silicon, gallium, germanium, and/or elements from the lanthanide series, to the compound in an amount of less than or equal to about 20 wt.% of the compound.Preferred Recovery: The method of recovering hydrogen involves contacting a diffusion multiple having compounds of formula (II) in hydrogen to form a hydrogenated compound and heating the hydrogenated diffusion multiple to recover hydrogen.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred System: The hydrogen generation reactor is in fluid communication with down stream of a slurry production reactor, or a drying and separation reactor. The slurry production reactor is in fluid communication downstream of the drying and separation reactor. The hydride recycle reactor is in fluid communication with the slurry production reactor. A metal hydride slurry is transferred to the hydrogen generation reactor from a slurry production reactor. A regenerated metal hydride is transferred from the hydride recycle reactor to a slurry production reactor. Water is introduced into the hydrogen generation reactor. The hydrogen is generated in the hydrogen generation reactor by the use of heat from microwave radiation, convective heat or exhaust heat of fuel cell.