Hydrogen Generation From Hydrolysis of Ammonia-Borane Using Pd-Pvb 2 and Co-ni-p/Pd-tio 2 Under Stirred Conditions

Abstract

The employment of Pd-PVB-TiO 2 and Co-Ni-P/Pd-TiO 2 in hydrogen generation from the hydrolysis of ammonia-borane (H 3NBH 3, AB) under stirred conditions are reported. Both catalysts are found to be highly active, isolable, and reactivatable in the hydrolysis of ammonia-borane even at low concentrations and temperature. The Arrhenius activation energies were found to be 54.9 and 54.7 kJ mol -1 for the hydrolysis of ammonia-borane catalyzed by Pd-PVB-TiO 2 and Co-Ni-P/Pd-TiO 2, respectively. Maximum hydrogen generation rates in the hydrolysis of AB catalyzed by the Pd-PVB-TiO 2 catalyst (1.5 mM) are 1910 and 14,800 mL H 2 min -1 (g Pd) -1 at 25 and 55 ± 0.5 °C, respectively. The maximum hydrogen generation rates are 170 and 1390 mL H 2 min -1 (g catalyst) -1 for the hydrolysis of AB catalyzed by Co-Ni-P/Pd-TiO 2 (25 mg) at 25 °C and 55 ± 0.5 °C, respectively. In comparison to unstirred conditions, these results demonstrate that a significant external mass transfer resistance caused by the desorbed metaborate by-products exist in the under unstirred conditions. © 2012 Elsevier B.V. All rights reserved.