Interface electronic coupling in FeOOH-Co9S8 heterostructure for efficient oxygen evolution reaction

The oxygen evolution reaction (OER) is a four-electron-proton coupling process with a high kinetic energy barrier, which affects the overall efficiency of water splitting. Rational construction of specific interfaces and optimization of electron interactions can effectively promote the kinetic behavior of OER. Herein, ultrathin FeOOH nanosheets were loaded on Co9S8 nanorods by hydrothermal method to construct heterogeneous structures (FeOOH-Co9S8/NF), and the modulation of catalytic activity by structural changes in the phase interface region was investigated. FeOOH-Co9S8/NF showed excellent performance as an OER catalyst, requiring an overpotential of only 215 mV to reach 100 mA cm-2. The rich heterogeneous interface can optimize the coordination environment of the Co site by redistributing the interfacial charge to obtain the appropriate chemisorption strength of oxygen-containing intermediates. This paper explores the relationship between interfacial electronic structure changes and catalyst performance enhancement, and provides an experimental basis for further practicalization of OER catalysts.