Tuning octahedron sites in MnFe2O4 spinel by boron doping for highly efficient seawater splitting

Seawater splitting requires highly active and stable electrocatalysts to sustain electrolysis without chloride corrosion, especially for the anode. Herein, a boron (B) doped MnFe2O4 spinel-type electrocatalyst with a heterostructure was derived from MnFe-MOF-74 precursor and applied for seawater electrolysis. It is found that the introduction of B species can effectively optimize the electronic configuration of MnFe2O4 with the promoted electron transfer ability between neighboring O to FeOh, thereby significantly reducing the energy barrier of the electron transfer and boosting the reaction process. As expected, in the real seawater environment, it required a low overpotential of 330 mV for oxygen evolution reaction (OER) to drive a current density of 100 mA cm−2 at 60 ℃, and exhibited high stability for over 200-h continuing test without producing hypochlorite and corrosion. This work provides a new strategy for enhancing the intrinsic activity of spinel-type oxides in seawater splitting.