Sub-3-nm High-Entropy Metal Sulfide Nanoparticles with Synergistic Effects as Promising Electrocatalysts for Enhanced Oxygen Evolution Reaction

Both high-entropy materials and metal–organic frameworks (MOFs) can be used as efficient catalysts for oxygen evolution, but it remains a challenge to combine their advantages to further improve the oxygen evolution reaction (OER). Herein, MOFs are served as precursors to prepare the high-entropy metal sulfide (HEMS) (MnFeCoNiCu)S2 nanoparticles based on the maximized configurational entropy theory, exhibiting ultra-efficient OER performance. The strong synergistic effect among Mn, Fe, Co, Ni, and Cu builds a stable electronic structure and provides a favorable local coordination environment, which enhance the catalytic performance greatly. In addition, the appropriate doping of sulfur source contributes to modulate the electronic structure, which promotes the formation of single-phase HEMS nanoparticles with the dimeter of sub-3 nm. The (MnFeCoNiCu)S2 nanoparticles display the best OER performance (a low overpotential of 221 mV at 10 mA cm–2 in 1 M KOH solution) and good stability (remains to be 97.6% after 12 h by chronoamperometry). This work provides a potential application for high-entropy materials based on MOF precursors as OER catalysts.