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

• Published in: Journal of power sources Vol. 210; pp. 184 - 190
• Main Authors: Rakap, Murat, Kalu, Egwu Eric, Özkar, Saim
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2012; Elsevier
• Subjects: Alternative fuels. Production and utilization; Ammonia-borane; Applied sciences; Cobalt; Energy; Exact sciences and technology; Fuels; Hydrogen; Hydrogen generation; Hydrolysis; Nickel; Palladium; Hydrolysis; Palladium; Nickel; Hydrogen generation; Ammonia-borane; Cobalt; Borazane; Mass transfer; Titanium oxide; Activation energy; By product; Catalyst; Comparative study; Hydrogen production; Low temperature
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.03.025

► By-product coverage causes a significant external mass transfer resistance. ► Pd–PVB–TiO2 and Co–Ni–P/Pd–TiO2 are active catalysts in the hydrolysis of H3NBH3. ► Pd–PVB–TiO2 provides max HG rate of 14,800mLH2min−1 (gPd)−1 at 55±0.5°C. ► Co–Ni–P/Pd–TiO2 provides max HG rate of 1390mLH2min−1(gcat)−1 at 55±0.5°C. ► HG rate is independent of H3NBH3 under stirred condition. 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.