TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The lithium, magnesium, sodium, potassium, calcium and aluminum are disposed in at least one hole in the substrate. At least one reactant is disposed in the substrate and forms a binary couple or ternary triple, upon heat treatment. At least two reactants are disposed in the substrate and forms ternary triple upon heat treatment. The method for making combinatorial library further involves identifying and analyzing at least one phase of the diffusion couple using electron microprobe analysis, slicing and grinding the diffusion multiple, analyzing the diffusion multiple by electron microprobe analysis or electron backscatter diffraction. The slicing and grinding of the diffusion multiple are performed after heat treatment. Determination of the suitability of at least one phase for absorption of hydrogen is performed by time of flight secondary mass ion spectrometry, thermal imaging or by using tungsten oxide detector. The method of regenerating hydrogen further involves adding a dopant comprising titanium, vanadium, zirconium, yttrium, lanthanum, nickel, manganese, cobalt, silicon, gallium, germanium and elements from lanthanide series, to the compound in an amount of at most20 wt.% of diffusion multiple. Heating is effected by the heat from exhaust of fuel cell. The sum of (a-f) of the compound of diffusion multiple is 1.Preferred Source: Heating is performed using microwave radiation, convectional heating and/or electrical resistive heating.Preferred Conditions: Heat treatment is performed at 580-900degreesC when the substrate is silicon, 580-1250degreesC when the substrate is silicon boride or silicon carbide, or 600-1250degreesC when the substrate is silicon nitride.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Reactor: The hydrogen generation reactor is in fluid communication with and downstream of a slurry production reactor. The hydrogen generation reactor is in fluid communication with and upstream of a drying and separation reactor. The slurry production reactor is in fluid communication with and downstream of drying and separation reactor. The hydride recycle reactor is in fluid communication with slurry production reactor.Preferred Method: A metal hydride slurry is transferred to the hydrogen generation reactor from slurry production reactor. A regenerated metal hydride is transferred from hydride recycle reactor to slurry production reactor. Water is introduced into the hydrogen generation reactor. Hydrogen is generated in the hydrogen generation reactor by the use of heat from microwave radiation, convective heat, exhaust heat from fuel cell.