Improved OER Performance at High Current Density for the CuCo2S4@MIL-53(Fe) Composite Electrocatalyst

Abstract

Transition metal sulfides (TMS) have drawn increasing research interest owing to their unique electronic structure. They hold broad prospects in accelerating the sluggish oxygen evolution reaction (OER) during water electrolysis. Metal-organic frameworks (MOFs) feature controllable electronic structures and specific surface areas, which facilitate the adsorption of reactants and expedite interfacial electron transfer. Leveraging the above-mentioned advantages of the two materials, a kind of composite electrocatalyst, CuCo₂S₄@MIL-53(Fe)/NF, was synthesized by growing MIL-53(Fe) in-situ onto CuCo₂S₄ nanowires supported on nickel foam. This composite electrocatalyst can accelerate charge transfer, significantly increase the number of active sites, and enhance both electrocatalytic activity and stability. The electrocatalyst CuCo₂S₄@MIL-53(Fe)/NF can drive the OER with an overpotential of 390 mV at a current density of 100 mA·cm⁻². Moreover, it still demonstrates excellent catalytic activity after 75 h of testing. This study not only broadens the avenues for sulfide composites but also provides an experimental basis and support for the direct combination of metal chalcogenides and Fe-based MOFs as electrocatalysts.