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 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 17740 min−1 based on the Pt loading for the 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.