NiN/CoN nanosheet heterojunction electrocatalyst for hydrogen evolution reaction in alkaline fresh water/simulated seawater

Ni 3 N/Co 4 N nanosheet arrays on nickel foam were fabricated by using simple hydrothermal and nitriding two-step strategies. Their excellent performance is due to the synergistic effect between Ni 3 N and Co 4 N, the sufficient exposed active spots and the overall interaction of the three-dimensional cross-linking network formed by the nanosheet arrays and the porous nickel foam. Ni 3 N/Co 4 N exhibits high hydrogen evolution reaction activity. To yield a current density of 10 mA cm −2 , Ni 3 N/Co 4 N requires overpotentials of 58 and 85 mV in alkaline fresh water and simulated seawater, respectively. This work provides new understanding of developing feasible heterostructured electrocatalysts based on transition metal nitrides. The Ni 3 N/Co 4 N nanosheet heterojunction exhibits higher HER activity in alkaline fresh water and simulated seawater.