Dehydrogenation of Ammonia Borane by Platinum‐Nickel Dimers: Regulation of Heteroatom Interspace Boosts Bifunctional Synergetic Catalysis

Regulation of the atom‐atom interspaces of dual‐atom catalysts is essential to optimize the dual‐atom synergy to achieve high activity but remains challenging. Herein, we report an effective strategy to regulate the Pt1‐Ni1 interspace to achieve Pt1Ni1 dimers and Pt1+Ni1 heteronuclear dual‐single‐atom catalysts (HDSACs) by tailoring steric hindrance between metal precursors during synthesis. Spectroscopic characterization reveals obvious electron transfers in Pt1Ni1 oxo dimers but not in Pt1+Ni1 HDSAC. In the hydrolysis of ammonia borane (AB), the H2 formation rates show an inverse proportion to the Pt1‐Ni1 interspace. The rate of Pt1Ni1 dimers is ≈13 and 2 times higher than those of Pt1 and Pt1+Ni1 HDSAC, manifesting the interspace‐dependent synergy. Theoretical calculations reveal that the bridging OH group in Pt1Ni1 dimers promotes water dissociation, while Pt1 facilitates the cleavage of B−H bonds in AB, which boosts a bifunctional synergy to accelerate H2 production cooperatively. A Pt1Ni1/C3N4 dimeric catalyst exhibits a much higher activity than Pt1/C3N4 in the hydrolytic dehydrogenation of ammonia borane for hydrogen generation. A bifunctional synergy is revealed in which the bridging OH in Pt1Ni1 oxo dimers promotes H2O dissociation, while Pt1 facilitates the cleavage of the B−H bond, thus cooperatively accelerating hydrogen production.