Interfacial Engineering of Two-Dimensional MoN/MoO2 Heterostructure Nanosheets as a Bifunctional Electrocatalyst for Overall Water Splitting

It is still a challenge to realize the dream of a hydrogen-based economy using a robust catalyst for overall water splitting. Here, we introduce two-dimensional MoN/MoO2 heterostructure nanosheets using nickel foam as a substrate for water splitting. The heterojunction formation was achieved through the partial nitriding of a Mo-based precursor to MoN in the annealing process under NH3 environment. The heterogeneous interface between MoN and MoO2 as active sites is supposed to improve the surface reaction kinetics and electronic conductivity. Therefore, an excellent performance is achieved when MoN/MoO2 is employed as both cathode and anode electrocatalysts; the corresponding cell voltages are 1.57 and 1.84 V at 10 and 100 mA cm(-2) in 1 M KOH, respectively. The promising bifunctional catalytic performance of our catalyst opens up a new way for efficient electrochemical water splitting.