Interfacial microenvironment regulation of FeOOH/S-Co heterostructure catalysts via S atoms for overall water splitting

Abstract

The rational design of interfacial structures provides more opportunities to improve the performance of heterogeneous catalysts for water splitting. However, they still suffer from high oxygen and hydrogen evolution reaction (OER and HER) overpotentials and sluggish kinetics. Herein, a novel interfacial S-atom-regulated metallic Co and FeOOH heterostructure catalyst on Ni foam (FeOOH/S-Co/NF) is designed for alkaline water splitting with high performance. The FeOOH/S-Co/NF catalyst exhibits low overpotentials of 264 and 27 mV at 10 mA cm⁻², and 294 and 108 mV at 100 mA cm⁻² for OER and HER, respectively, with high stability. When serving as a bifunctional catalyst, only 1.576 V is required to drive 10 mA cm⁻². In situ Raman spectroscopy and theoretical calculations validate that interfacial microenvironment regulation optimizes the adsorption of OER and HER intermediates and reduces the thermodynamic energy barrier of the OER reaction. This study provides a new strategy and insight for designing efficient metal-compound heterostructure electrolytic water catalysts.