Synergistic catalysis at in situ-formed Pt–NiOOH nanodot interfaces for highly efficient ammonia borane hydrolysis†

Abstract

Hydrolysis of ammonia borane (AB) comprising multiple intermediate steps is a representative catalytic reaction for hydrogen generation, usually requiring noble metal Pt as a catalyst. Constructing heterostructures is an effective strategy to improve the catalytic activity while reducing Pt usage. Herein, tailored nanodot–nanodot heterostructures of Pt–Ni(OH)_x on reduced graphene oxide (RGO) are realized by the one-step solvothermal method. It is intriguingly found that local NiOOH nanodots, rather than Ni(OH)₂, are in situ formed when encountering Pt on RGO, forming the heterointerface. Subsequently, the optimized Pt–Ni(OH)_x/RGO catalyst exhibits the highest turnover frequency (TOF) of 17 740 min⁻¹ based on the Pt loading for hydrogen generation from AB hydrolysis at 303 K, which is 28 times as high as that of Pt/RGO. Theoretical calculations reveal that the heterojunction catalyst promotes the chemisorption and dissociation of water molecules, accelerating H₂ generation from AB hydrolysis. This one-step solvothermal method to produce the Pt–Ni(OH)_x/RGO catalyst provides a general route to high-performance nanodot–nanodot heterostructure catalysts for various hydrogen-generation catalytic domains.