Two-dimension on two-dimension growth: hierarchical Ni(0.2)Mo(0.8)N/Fe-doped Ni(3)N nanosheet array for overall water splitting

Developing advanced electrocatalysts with low cost for electrocatalytic water splitting are highly desirable. Herein, we report the design of two-dimension on two-dimension growth of hierarchical Ni(0.2)Mo(0.8)N nanosheets on Fe-doped Ni(3)N nanosheets supported on Ni foam (Ni(0.2)Mo(0.8)N/Fe–Ni(3)N/NF) via hydrothermal reaction and nitridation treatment. In the hierarchical structures, small Ni(0.2)Mo(0.8)N nanosheets were uniformly anchored on Fe–Ni(3)N nanosheets. Due to enhanced electron transfer between Ni(0.2)Mo(0.8)N and Fe–Ni(3)N, Ni(0.2)Mo(0.8)N/Fe–Ni(3)N/NF exhibits superior electrocatalytic activity for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). After stability tests for 50 h, Ni(0.2)Mo(0.8)N/Fe–Ni(3)N/NF exhibits negligible degradation of the current density for the OER (91% remain) and HER (95% remain), suggesting excellent stability. Owing to the outstanding performance, Ni(0.2)Mo(0.8)N/Fe–Ni(3)N/NF display a cell voltage of 1.54 V (10 mA cm(−2)) for electrocatalytic overall water splitting.