Sulfate modified Fe(OH)x/NF nanosheets with oxygen vacancies for enhanced oxygen evolution

The development of cost-effective and high-performance electrocatalysts for oxygen evolution reaction (OER) would be beneficial to future renewable energy storage. Herein, sulfate modified Fe(OH)_x nanosheets grown on nickel foam (S–Fe(OH)_x/NF) with rich undercoordinated atom centers and oxygen vacancies were fabricated through a facile hydrothermal method. The optimal sample S₂–Fe(OH)_x/NF exhibits outstanding OER activity with an ultralow overpotential of 261 mV to obtain a current density of 200 mA cm⁻². The impressive catalytic activity is primarily attributed to the introduction of the undercoordinated atom (Fe) center, which offer rich active sites, as well as the creation of oxygen vacancies (Vo) that enhance the electron density and the intrinsic conductivity. This work opens up an in-depth understanding of transition metal oxides for OER mechanism by sulfate-decorated and a new prospect for designing highly efficient electrocatalysts.