Chainmail catalyst of ultrathin P-doped carbon shell-encapsulated nickel phosphides on graphene towards robust and efficient hydrogen generation

Abstract

Transitional metal phosphides are potential candidates for replacing benchmark noble metal catalysts, but they suffer from electrochemical leaching/corrosion during hydrogen evolution. Herein, we report a core–shell structured chainmail catalyst composed of Ni₂P nanoparticles wrapped by ultrathin phosphorous-doped carbon shells on the graphene network. Benefiting from the unique architecture, this hybrid catalyst needed overpotentials of only 110 mV and 150 mV to reach 10 mA cm⁻² hydrogen evolution current density in 0.5 M H₂SO₄ and 1.0 M KOH for more than 24 h, respectively. Theoretical analysis revealed that the strong electronic interactions between ultrathin carbon shell and inner Ni₂P core, phosphorus dopant and neighboring carbon in the shell were responsible for the enhanced electrochemical activity. This study offers not only an effective method to prepare the efficient chainmail catalysts, but also valuable insights for future design of core–shell structures through electronic modulation to enhance the activity and stability of such catalysts.