Bimetallic Co-Mo nitride nanosheet arrays as high-performance bifunctional electrocatalysts for overall water splitting

Developing non-precious metal electrocatalysts with high activity and stability are of great significance to achieve overall water splitting. In this work, cobalt-molybdenum nitride nanosheet arrays grown on Ni foam (CoMoN x NSAs/NF) were prepared via a facile hydrothermal and nitridation process. The resulting CoMoN x NSAs/NF not only has a specific large surface area and provides more active sites but also possesses good electrical conductivity, contributing to the fast reaction kinetics. Furthermore, the synergistic effect between Co 2 N and Mo 2 N cooperatively enhance the charge transfer, thus further improving the electrocatalytic activity. Benefiting from these merits, the optimal CoMoN x -500 NSAs/NF exhibits excellent activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with overpotentials of 91 and 231 mV at the current density of 10 mA cm −2 , respectively. Moreover, the CoMoN x -500 NSAs/NF||CoMoN x -500 NSAs/NF couple requires a low cell voltage of 1.55 V at the current density of 10 mA cm −2 , which is much superior to many other reported transition metal nitrides catalysts. This present work provides a reference for the design of bimetallic nitrides with superior electrocatalytic performance for   overall water splitting.