NOVELTY - At least one reactant is disposed in a substrate comprising boron, boron nitride or boron carbide. The reactant is lithium, magnesium, sodium, potassium, calcium and/or aluminum. The substrate is heated, and a diffusion couple having at least two phases is formed. The diffusion couple is contacted with hydrogen, and absorption and/or desorption of hydrogen is detected. Thus, a combinatorial library is made and screened.    USE - For making and screening combinatorial library used for storing and recovering hydrogen used for generating energy (all claimed) in fuel cell application for automobiles, homes and apartments.    ADVANTAGE - The method effectively enables the storage and recovery of hydrogen. The creation of large number of controlled compositional variations in bulk samples for fast and systematic survey of hydrogen storage property of boride, borocarbide and boronitride, is enabled.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) recovery of hydrogen. Hydrogen is contacted with at least one compound chosen from aluminum boride (AlB2 or AlB12), calcium boride (CaB6), potassium boride (KB6), lithium boride (LiB12, LiB6, LiB4, LiB3, LiB2, LiB, Li7B6 or Li3B), magnesium boride (MgB2, MgB4 or MgB7), sodium boride (NaB6, NaB15 or NaB16), and a hydrogenated compound is produced. The hydrogenated compound is heated, and hydrogen is recovered;    (2) energy generation device, which generates energy by recovering hydrogen;    (3) diffusion multiple, which contains compound of formula: (Lia, Nab, Kc, Ald, Mge, Caf)x(B,C,N)y, where Li is lithium, Na is sodium, Mg is magnesium, K is potassium, Ca is calcium, Al is aluminum, B is boron, C is carbon, N is nitrogen, a-f are 0-1, preferably 1, and x,y are 1-22;    (4) composition, which contains hydride of compounds chosen from aluminum boride (AlB2 or AlB12), calcium boride (CaB6), potassium boride (KB6), lithium boride (LiB12, LiB6, LiB4, LiB3, LiB2, LiB, Li7B6 or Li3B), magnesium boride (MgB2, MgB4 or MgB7), and sodium boride (NaB6, NaB15 or NaB16); and    (5) system for storage and recovery of hydrogen, which has a hydrogen generation reactor in fluid communication with a hydride recycle reactor. The hydrogen generation reactor utilizes hydrides of light metal boride, borocarbide and boronitride to recover hydrogen.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the arrangement of diffusion multiple assembly comprising boron substrate.