Plasma-Engraved Co₂N Nanostructures toward High-Performance Alkaline Hydrogen Evolution

Hydrogen generated by electrochemical water splitting is an attractive alternative to fossil fuels. Herein, we developed hollow-like Co₂N nanoarrays that serve as electrocatalysts for the hydrogen evolution reaction (HER) with surface engineering by argon plasma. The argon plasma-engraved Co₂N nanoarrays (Ar-Co₂N/CC) represent a dramatic catalytic performance for the HER with an overpotential of 34 mV at a current density of 10 mA cm^-2 in an alkaline electrolyte, as well as outstanding durability of 240 h. Characterization experiments and density functional theory (DFT) calculations suggest that the enhanced HER activity is due to the rational coordination environment of Co, which can be tuned by Ar plasma engraving. Based on our research, one new view for conducting exceptional catalyst surface modification engineering via plasma engraving might be established.