Chemical hydrogen storage using polynuclear borane anion salts

The polynuclear borane anions nido-B₁₁H₁₄⁻, closo-B₁₀H₁₀²⁻ and closo-B₁₂H₁₂²⁻ undergo heterogeneous transition metal-catalyzed hydrolysis to generate hydrogen. The rate of hydrolysis is dependent upon the concentration of polynuclear borane anions and surface area of the metallic catalyst. The aqueous solutions of polynuclear borane anions, especially the closo-B₁₀H₁₀²⁻ and closo-B₁₂H₁₂²⁻ dianions, are very stable for an extended period of time (years) in the absence of catalyst and spontaneously generate hydrogen in the presence of a rhodium metal catalyst. These polynuclear borane anions have a high potential for use in portable hydrogen storage systems without requiring high pH aqueous media for storage as in the case of NaBH₄.