Interface engineering of Fe-Sn-Co sulfide/oxyhydroxide heterostructural electrocatalyst for synergistic water splitting

To realize large-scale hydrogen production by electrolysis of water, it is essential to develop non-precious metal catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Here, we fabricate Sn-, Fe-, and Co-based sulfide/oxyhydroxide heterostructural catalyst on nickel foam (FeSnCo_0.2S_xO_y/NF) by solvothermal method. The FeSnCo_0.2S_xO_y/NF requires low overpotentials of 48 and 186 mV at 10 mA·cm^–2, respectively, for HER and OER. When it is assembled into an electrolytic cell as a bifunctional electrocatalyst, it only needs 1.54 V to reach 10 mA·cm^–2, far better than IrO₂||Pt/C electrolyzer. The formation of sulfide/hydroxide heterostructural interfaces improves the electron transfer and reduces the reaction energy barrier, thus promoting the electrocatalytic processes.