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

Abstract 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.