Pd-doped Cu nanoparticles confined by ZIF-67@ZIF-8 for efficient dehydrogenation of ammonia borane

To exploit the low-cost and efficient catalyst for the hydrolytic dehydrogenation of ammonia borane, trace amount of palladium-doped transition metal (Cu, Ni, Co, Fe and Zn) nanoparticles have been incorporated into the interior of metal-organic frameworks named ZIF-8, ZIF-67, ZIF-67/ZIF-8 and core-shell ZIF-67@ZIF-8 by a double-solvent approach. The optimized catalyst of CuPd0.01@ZIF-67@ZIF-8 composite exhibited an excellent activity with a turnover frequency (TOF) value of 30.15 mol H-2 (mol(metal))(-1) min(-1) at 298 K and a relatively low activation energy of 38.78 kJ mol(-1). It might attributed to both ultrafine size of metal nanoparticles (-3 nm) induced by the confinement of core-shell ZIF-67@ZIF-8 and the synergistic effect between Pd and Cu. Moreover, the detailed kinetic study has manifested that this catalytic reaction is first-order in regards to the catalyst amount while zero-order as for the concentration of ammonia borane. In addition, the durability and recyclability of CuPd0.01@ZIF-67@ZIF-8 have been demonstrated to be great. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.