Breaking the activity-stability trade-off in ammonia borane hydrolysis via atomically engineered platinum single atom-nickel cluster synergistic interfaces

Atomically dispersed heterometal catalysts offer ultrahigh atomic utilization and defined heterointerfaces for superior catalytic performance compared to single-metal-site analogues, yet their precise atomic-level construction remains challenging. Herein, a structure-defined atomic-cluster catalyst (Pt_SANi_C/CNT) is synthesized via sequential atomic layer deposition (ALD). This strategy enables atomic-scale engineering of Pt surface exposure and electronic properties through controlled ALD cycles. The optimized Pt_SANi_C/CNT exhibits exceptional activity and durability for ammonia borane (AB) hydrolytic dehydrogenation, breaking the activity-stability trade-off with 9.6-fold and 1.4-fold higher activity than Pt_SA/CNT (single-atom) and Pt_SANi_SA/CNT (dual-atom) catalysts, respectively. Through in situ X-ray absorption spectroscopy, kinetic and dynamic analysis, and DFT calculations, we elucidate that Pt_SANi_C interfacial sites synergistically promote concurrent H₂O adsorption-dissociation and H₂ desorption. Mechanistic studies reveal that nickel clusters facilitate H₂O activation while Pt single atoms favor B–H bond cleavage due to an upshifted d-band center. This interfacial synergy also enhances selective hydrogenation and O₂/H₂O₂-involved oxidation. The ALD-based atomic engineering approach provides a generalizable route to construct efficient and durable heterometal catalysts with defined active sites.