2D porous Co-Mo nitride heterostructures nanosheets for highly effective electrochemical water splitting

A significant issue in the overall water splitting process is the development of bifunctional non-precious metal catalysts with high performance. Herein, we designed and synthesized heterogeneous structure of Co5.47N/MoN (Co-Mo-N) porous nanosheets in situ grown on nickel foam substrates by thermal ammonolysis of CoMoO4 precursors. The special heterogeneous and porous nanosheet structure of Co-Mo-N not only provides abundance of active sites, but also accelerates the charge transfer due to the interaction between Co5.47N and MoN. Additionally, the differing energy band configurations of the various phases in heterostructure will cause charge transport at the interface, which would be advantageous for the surface electron modification of heterojunctions and further enhances the electrocatalytic performance. As a result, the Co-Mo-N heterostructure exhibited excellent OER and HER catalytic activity, with over potentials of 288 and 82 mV at 10 mA cm−2, respectively. When using Co-Mo-N heterostructures as cathodes and anodes to achieve overall water splitting, a low voltage of 1.59 V is required to achieve a current density of 10 mA cm−2. This research presents a novel approach to designing bifunctional non-precious metal catalysts for overall water splitting.