Enhancing ammonia decomposition for hydrogen production via optimization of interface effects and acidic site in supported cobalt-nickel alloy catalysts

[Display omitted] •Cobalt-nickel alloys excel in hydrogen production from ammonia decomposition.•CoNi/ZSM-5 exhibits the best ammonia decomposition activity.•CoNi-O bonds can be formed between CoNi alloys and carriers.•Rich CoNi-O bonds promote the activity via enhancing N-atom recombination.•Lewis acidic sites also improve ammonia decomposition efficiency. Cobalt-nickel-based catalysts are among the most promising non-noble metal catalysts for hydrogen production via ammonia decomposition. However, attaining the optimal bonding ratio at the CoNi alloy-support interface remains a significant challenge for ensuring sufficient catalytic activity in ammonia decomposition. To address this issue, this study investigates the enhancement of catalytic activity through the interface effects between CoNi alloy nanoparticles and different supports (ZSM-5, Al2O3, and TiO2), as well as the role of Lewis acid sites within the supports. It is found that the CoNi alloy particles supported on the carriers form CoNi-O bonds with oxygen atoms, creating an oxide-metal interface that facilitates charge transfer from the carrier to the alloy, promoting catalytic activity. In the CoNi/ZSM-5 catalyst, the abundant formation of CoNi-O bonds enhances the interfacial effects and promotes charge transfer, thereby improving catalytic performance. Besides, the plentiful Lewis acid sites in ZSM-5 improve the ammonia adsorption and the increasing local ammonia concentration ensures more effective contact and enhances catalytic efficiency.