MoO3 crystal facets modulation by doping heteroatom Fe from polyoxometalate for quasi-industrial oxygen evolution reaction

The widespread implementation of water splitting urgently requires low-cost, effective and stable electrocatalysts for the industrial oxygen evolution reaction (OER) that can reach a large current density (>500 mA cm−2). Herein, we report a facile solvothermal strategy to fabricate a binder-free electrode of Fe-S-NiMoO4/MoO3 with nanorods array uniformly grown on a nickel-foam (NF). The Anderson-type polyoxometalate (NH4)3[FeMo6O24H6]·7H2O as the precursor has enabled an accurate and controllable Fe-doping in transition metal oxides (TMO). The combination of experiments and density functional theory (DFT) calculations reveal that Fe-doping is conductive to regulate the crystal plane of MoO3, modulate the electronic structure and improve the conductivity. Consequently, the Fe-S-NiMoO4/MoO3@NF electrode can yield 500 mA cm−2 at an overpotential of 271 mV and work steadily over 100 h under 50 °C that can meet the requirements of the industrial water electrolysis. This study provides a practical approach to design electrocatalysts for future industrial applications.