Hydrogen generation from hydrolysis of ammonia-borane using Pd–PVB–TiO2 and Co–Ni–P/Pd–TiO2 under stirred conditions

Abstract

The employment of Pd–PVB–TiO2 and Co–Ni–P/Pd–TiO2 in hydrogen generation from the hydrolysis of ammonia-borane (H3NBH3, 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 54.7kJmol−1 for the hydrolysis of ammonia-borane catalyzed by Pd–PVB–TiO2 and Co–Ni–P/Pd–TiO2, respectively. Maximum hydrogen generation rates in the hydrolysis of AB catalyzed by the Pd–PVB–TiO2 catalyst (1.5mM) are 1910 and 14,800mLH2min−1(gPd)−1 at 25 and 55±0.5°C, respectively. The maximum hydrogen generation rates are 170 and 1390mLH2min−1(gcatalyst)−1 for the hydrolysis of AB catalyzed by Co–Ni–P/Pd–TiO2 (25mg) 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.