An efficient amplification strategy for N-doped NiCo2O4 with oxygen vacancies and partial Ni/Co-nitrides as a dual-function electrode for both supercapatteries and hydrogen electrocatalysis

Abstract

To obtain transition-metal-oxide-based materials with remarkable energy storage and conversion performance, rational design and synthesis of electrodes with abundant active sites is crucial. Herein, we propose an effective strategy for nitrogen doping in NiCo₂O₄ (NCO) nanowire arrays using NH₃ plasma treatment. N-doped NCO contains oxygen vacancies with nitrogen atoms, nickel/cobalt nitrides, and high concentrations of Ni²⁺ and Co²⁺ within the structure, leading to high electrical conductivity. As expected, N-doped NCO electrodes exhibited excellent electrochemical performance for supercapacitors and hydrogen evolution reaction (HER) electrocatalysis in KOH electrolyte. This work provides a promising pathway toward developing advanced electrodes.