Uniform anchoring of MoS nanosheets on MOFs-derived CoFeO porous nanolayers to construct heterogeneous structural configurations for efficient and stable overall water splitting.

Rational interfacial engineering and morphology modulation are recognized as effective strategies to modulate the electronic structure and improving the activity of spinel materials. In this paper, we report a strategy of Fe-induced creation of porous nanolayers of CoFeO with unique morphology derived from MOFs by introducing ferrocene, and then constructed CoFeO/MoS heterostructures were fabricated by homogeneously anchoring MoS nanosheets onto the surface of CoFeO. The triple synergistic effect of heterogeneous interfaces, highly active Mo(IV) sites, and unsaturated S effectively accelerates the cycling process between Fe(III)/Fe(II) and Co(III)/Co(II), which in turn enhances the adsorption of reactive intermediates on the active sites, as further corroborates by density functional theory (DFT) calculations. As a result, the CoFeO/MoS heterostructured catalysts prepared without noble metals exhibit high catalytic performance, necessitating only 270 mV and 229 mV to achieve the current density of 100 mA·cm for OER and HER respectively, which is superior to most of the reported catalysts of interest. In addition, when used in an alkaline electrolyzer, it provides a current density of 10 mA·cm at 1.54 V cell voltage. This work provides a new way for the rational construction of bifunctional water electrolytic catalysts.