Engineering the abundant heterointerfaces of integrated bimetallic sulfide-coupled 2D MOF-derived mesoporous CoS2 nanoarray hybrids for electrocatalytic water splitting

Abstract An efficient and robust electrocatalyst was prepared for overall water splitting in alkaline media. The rational design of two-dimensional metal-organic framework (MOF)–derived mesoporous CoS2 nanoarrays coupled with FeS2@MoS2 layers shows enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The FeS2-MoS2@CoS2-MOF nanostructure demonstrates superior electrocatalytic activity toward the HER with an overpotential of 92 mV at 10 mA/cm2 and the OER with an overpotential of 211 mV at 20 mA/cm2. FeS2-MoS2@CoS2-MOF(+)||FeS2-MoS2@CoS2-MOF(−) delivered comparatively low cell voltages of 1.51, 1.66, and 1.78 V at current densities of 10, 50, and 100 mA/cm2, respectively, with remarkable stability for 30 h. The prepared electrocatalyst is the most efficient compared with previously reported results owing to the abundant heterointerfaces, mesoporous nanostructures, and multimetallic active centers, and it opens up the discussion for exploring MOF-based catalysts for overall water splitting applications. This work highlights the engineering of abundant heterointerfaces for improving HER/OER performance.