Ni/Ni3C core–shell nanoparticles encapsulated in N-doped bamboo-like carbon nanotubes towards efficient overall water splitting

Abstract

Developing a synthesis technique to control the morphology and component distribution of transition metal bi-functional electrocatalysts is of great significance for superior performance. Herein, a novel electrocatalyst has been synthesized via a one-step pyrolysis reaction of Ni(OH)₂ nanosheets and dicyandiamide under an argon atmosphere at relatively low temperature, in which Ni/Ni₃C core–shell nanoparticles were encapsulated in bamboo-like N-doped carbon nanotubes and the Ni₃C component was homogeneously distributed in the wall of the nanotubes. Ultrathin Ni(OH)₂ nanosheets prepared by solvothermal synthesis play an important role in the distribution of the Ni component and the formation of tube morphology. The core–shell nanoparticles and the homogeneously distributed Ni₃C component drastically enhance the catalytic performance. The as-prepared sample obtained by using optimized preparation conditions exhibits outstanding HER and OER activities in alkaline solution with an overpotential of 184 mV for the HER and 277 mV for the OER with a current density of 10 mA cm⁻² and long-term durability with a 10 h continuous test. Superior electrocatalytic performance is ascribed to the effect of unique morphology and composition distribution. Additionally, the catalyst shows excellent overall water splitting properties and high stability.