One-step synthesis and performances of Ni@CN nanocapsules with superior dual-function as electrocatalyst and microwave absorbent

Abstract

Developing high efficient, stable, and earth-abundant materials is still a great challenge both in the electrocatalytic and microwave absorption fields nowadays. Herein, we construct unique core-shell structured N-doped graphite coated Ni (Ni@CN) nanocapsules through a facile one-step arc-discharge method. The as-obtained Ni@CN show superior hydrogen evolution reaction (HER) activities with a low overpotential of 85 mV at 10 mA cm−2, a small Tafel slope of 69 mV dec-1, and strong long-term stability of 10 h. Besides, the Ni@CN nanocapsules exhibit high microwave absorption performance as microwave absorbers. Their optimal value of reflection loss (RL) is -35.8 dB at 11.7 GHz with a thickness of 2.3 mm. The dual-functional behavior of Ni@CN nanocapsules in catalytic and microwave absorption is due to their strong synergistic effect between the N-doped graphite shell and Ni core, the high electrical conductivity of Ni, and the abundant defects caused by the N doping into the graphite shell.