CoNi Nanoparticles Supported on Hierarchical SAPO-34 Zeolite as a Catalyst for the Hydrolytic Dehydrogenation of Ammonia Borane

Highly dispersed CoNi bimetallic nanoparticles (NPs) supported on hierarchical SAPO-34 zeolite were fabricated via impregnation followed by a hydrogen reduction method for ammonia borane (NH 3 BH 3, AB) hydrolysis to generate hydrogen. In order to investigate the effects of the Co/Ni weight ratio and zeolite synthesis procedure on the catalytic activity, Co x Ni y /SAPO-34 catalysts with various Co and Ni contents and zeolite particle sizes were prepared. It was found that Co 3.33 Ni 1.67 /SAPO-34-N containing 3.33:1.67 of the Co/Ni weight ratio and using nanosized hierarchical SAPO-34-N as support exhibited the highest catalytic activity among the investigated catalysts for the AB hydrolysis reaction, with a high turnover frequency (TOF) value of 9.25 mol H 2 (mol metal ·min) −1 at 30 °C, probably due to the promoted effect of nanosized hierarchical structure of SAPO-34 support on the dispersion and stabilization of CoNi particles as well as the synergistic catalysis of CoNi alloy NPs and Brønsted acid sites. Moreover, the Co 3.33 Ni 1.67 /SAPO-34-N catalyst also displayed excellent durability, with 83% of the catalytic activity of its initial state being preserved even after five cycles.