Group 4 oxides supported Rhodium(0) catalysts in hydrolytic dehydrogenation of ammonia borane

Rh3+ ions are first impregnated on Group 4 metal oxides (TiO2, ZrO2, HfO2) in aqueous solution and, then reduced with aqueous solution of NaBH4 to form rhodium(0) nanoparticles (NPs) on the oxide surface. The analyses reveal that Rh(0) NPs are highly dispersed on the surface of TiO2, ZrO2, HfO2. Rh-0/MO2 (M: Ti, Zr, Hf) NPs have high activity and reusability in releasing H-2 from the hydrolysis of ammonia borane with an initial turnover frequency of 643, 198, and 188 min(-1), respectively, at 25.0 +/- 0.1 degrees C. The reusability of Rh-0/ZrO2 and Rh-0/HfO2 catalysts is higher than that of the Rh-0/TiO2 catalyst. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.