A chainmail effect of ultrathin N-doped carbon shell on Ni₂P nanorod arrays for efficient hydrogen evolution reaction...

Exploring innovation strategies has huge potential to significantly improving both activity and stability of current catalysts. Here, a chainmail design is proposed to enable the electronic interaction of ultrathin nitrogen-doped carbon shell with Ni₂P nanorod core arrayed on nickel foam (Ni₂P@NC/NF) for simultaneously promoting the activity and stability in both alkaline and neutral hydrogen evolution reaction (HER). The easy penetration of valence electrons from active Ni₂P core to NC shell enables the obvious improvement of HER performance compared to pure Ni₂P. In 1 M KOH and 1 M PBS solution, the resultant Ni₂P@NC/NF requires the ultralow overpotentials of only 93 and 96 mV to drive the current density of 10 mA cm^-2 with the Faradaic efficiency of 96% and 94%, respectively. Remarkably, such a chainmail design also reveals an obviously improved stability with almost negligible performance degradation under the current density of 20 mA cm^-2 for 30 h. Theoretical calculations confirm that the nitrogen-doped carbon shell improves the durability of transition metal phosphides by increasing the dissolution resistance of Ni atoms. The proposed concept may create a new pathway for synchronizing high activity and robust stability in manipulating heterogeneous catalytic properties.