Metal-organic framework derived Co3O4@Mo-Co3S4-Ni3S2 heterostructure supported on Ni foam for overall water splitting

Effective bifunctional catalysts are desirable to replace precious metal materials to promote the development of electrochemical water splitting. Facing with challenge, it is important to design and construct bifunctional electrocatalysts. Herein, we present a highly efficient multifunctional electrocatalyst, i.e., metal-organic framework derived Co3O4@Mo-Co3S4-Ni3S2/NF. (NF: nickle foam). Nano-flowers supported by the nanorods directly grown on the conductive substrate are achieved by doping non-3d high-valence metal Mo during the sulfurization process of ZIF-67 precursor. As a result, the obtained Co3O4@Mo-Co3S4-Ni3S2/NF heterostructure shows outstanding electrochemical performance. Specifically, the low overpotentials of 295 mV and 116 mV are obtained at the current densities of 50 mA cm-2 and 10 mA cm-2 for OER and HER in an alkaline solution, respectively. Moreover, Co3O4@Mo-Co3S4-Ni3S2/NF exhibited excellent catalytic activity with a current density of 10 mA cm-2 at a low voltage of 1.62 V for overall water splitting. This study may provide new methods for metal doping and rationally constructing heterostructure to improve electrochemical performance of catalysts, and is expected to help accelerate progress towards the non-precious metal electrocatalysts for overall water splitting.