Colloidal Synthesis of Thiospinel High-Entropy Sulfide Star-like Nanocrystals with High Cycling Stability for the Oxygen Evolution Reaction.

High-entropy semiconducting nanocrystals involving the random incorporation of five or more metals within a single, disordered lattice are receiving significant research interest as catalytic materials. Among these, high-entropy sulfide (HES) nanocrystals demonstrate potential as electrocatalysts but have been slower to gain research interest compared to other high-entropy systems due to the complications introduced by multistep, high-temperature synthesis techniques and the issues of material stability during performance. In this work, we report a simple, reproducible, and scalable HES synthesis to produce star-like nanocrystals. The HES nanocrystals show promise as electrocatalysts with high stability by maintaining a uniform overpotential within 1.5% of the initial value for over 2,200 cycles while rotating, with values as low as 313 mV at 10 mA/cm for the oxygen evolution reaction (OER) in alkaline media. Our work provides a low-temperature, colloidal method in the formation of highly complex, phase-pure thiospinel high-entropy sulfide nanocrystals.