Amino Pre-Coordination Confinement-Induced PtCo Ordered Intermetallics with Declined H₂O Dissociation Barrier for Boosted Ammonia Borane Hydrolysis

Hydrolysis of ammonia borane is deemed as a promising technique for robust hydrogen production, yet its deployment is still restricted due to the sluggish kinetics of the water dissociation step. An appropriate catalyst that can effectively reduce the H₂O dissociation barrier is quite desirable for sustainable ammonia borane-to-hydrogen conversion. Herein, an amino pre-coordination confinement strategy is profiled to achieve sub-2 nm ordered PtCo intermetallics uniformly on N-doped hollow mesoporous carbon spheres (O-PtCo/NHMS) for ammonia borane catalytic hydrolysis. Such a confined approach showcases the capacity of preventing nanoparticles from agglomeration and growth for accurate size control and can be extended to other ordered intermetallic systems (e.g. PtFe and PtCu). As for the ammonia borane hydrolysis, the ordered PtCo intermetallics have delivered a five times higher turnover frequency activity of 1264.1 min⁻¹ than that of the disordered PtCo catalyst, together with excellent catalytic durability. Mechanism studies indicate that the ordered PtCo structure promotes the balanced adsorption of H₂O and ammonia borane molecules at Co and Pt sites and reduces the energy barrier for the rate-determining H₂O dissociation step to boost the ammonia borane hydrolysis. This work provides valuable insights into the rational design of efficient ordered PtM intermetallic catalysts and expands their application in hydrogen production via ammonia borane hydrolysis.