Synergistic catalysis of Fe-Co bimetallic sulfides for efficient water splitting

As is well known that, transition metal sulfides often face challenges such as excessive intermediate adsorption and poor electrical conductivity, which greatly limits their use in large-scale water electrolysis. Herein, we prepare a Fe-Co bimetallic synergistic catalyst based on solvothermal method. This catalyst ((FeCo) 9 S 8 /C-1) exhibits excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance due to multiple synergistic effects. For instance, low overpotentials of 284.7 mV for OER and 310 mV for HER at 10 mA·cm −2 could be reached in 1 M KOH, while the electrochemical active surface area reaches 40.25 m 2 ·g −1 , which is twofold compared to bare Co 9 S 8 . Density Functional Theory (DFT) calculations further reveal the strong charge transfer between Fe and Co would reduce the energy barriers for the rate-determining steps, enhancing the desorption of *OOH and *H intermediates, as well as improving the electrocatalytic efficiency. This study opens new avenue for designing other dual-transition metal sulfides for water splitting with high-performance.