A self-supported S-doped Fe-based organic framework platform enhances electrocatalysis toward highly efficient oxygen evolution in alkaline media

Abstract

The oxygen evolution reaction (OER) is a great crucial half-reaction in many energy conversion and storage techniques to alleviate the problems of the energy crisis and environmental pollution. However, the development of a low-cost and easy-to-prepare OER electrocatalyst with glorious performance and superior stability remains a huge challenge. Recently, metal–organic frameworks (MOFs) have attracted tremendous interest owing to their charming features including ultrafine porosity, rich active metal sites and tunable structures. However, most MOFs directly acting as electrocatalysts for the OER have intrinsic low electrical conductivity, poor electrochemical activities and short-term durability, hindering their practical application. Herein, we develop a facile and effective one-pot solvothermal method to rationally design a new S-doped Fe-based organic framework grown on nickel foam (NF), which prominently boosts the OER performance. Specifically, S_0.05–Fe-BTB/NF exhibits remarkable OER activity with an ultralow overpotential of only 231 mV to afford 20 mA cm⁻² current density without iR drop compensation in alkaline media, as well as a small Tafel slope of 41 mV dec⁻¹, superior to that of the commercial RuO₂ electrocatalyst. Particularly, it also demonstrates outstanding catalytic durability under an overpotential of 235 mV for 50 h. More significantly, the probable active species during the OER process are determined to be the electrochemically transformed metal oxyhydroxide.