Hydrogen generated from hydrolysis of ammonia borane using cobalt and ruthenium based catalysts

Ammonia borane (NH3BH3, AB), one kind of promising hydrogen storage materials, is hydrolyzed to produce hydrogen in presence of HCl, Co/IR-120 and Ru/IR-120 catalysts. The kinetics analysis of the AB hydrolysis shows that hydrogen production is of the first-order reaction in regard to both concentrations of ammonia borane and catalysts initially present, respectively. The hydrolyzate of ammonia borane after hydrogen evolution is also characterized with XRD, FT-IR and 11B NMR. Boric acid (H3BO3) is found to be the dominant product in the hydrolyzate. Besides, the produced gas is discovered to contain both hydrogen and ammonia according to the GC–MS analysis and the indophenol colorimetric analysis. A possible reaction pathway on hydrogen generation from hydrolysis of ammonia borane is, accordingly, proposed based on the existence of boric acid, hydrogen and ammonia in the products. The total life cycle of ammonia borane is also proposed to illustrate formation of different intermediates during the AB hydrolysis for hydrogen generation and a possible regeneration scheme of the spent ammonia borane.

► Hydrogen is produced from hydrolysis of ammonia borane in presence of light-weight Co or Ru catalysts. ► The hydrolysis reaction of ammonia borane is of the first-order in concentrations of ammonia borane and catalysts. ► Ammonia is conjointly produced with hydrogen from hydrolysis of ammonia borane, and can be reduced with proper management of exothermic reaction heat. ► Boric acid is the major hydrolyzate of ammonia borane for hydrogen evolution.