1 min synthesis of phase pure nanocrystalline high-entropy sulfides for efficient water electrolysis

The development of noble-metal free electrocatalysts with low production cost is of utmost importance for sustainable water electrolysis. Herein, we present a fast flexible synthesis pathway for the preparation of a variety of different medium- and high-entropy spinel sulfides of various compositions, using a non-aqueous microwave-assisted synthesis without any H₂S. Nanoparticulate high-entropy sulfides containing up to 8 different metal cations can be obtained after an extremely short synthesis time of only 1 min and comparatively low temperatures of 200–230°C. We further demonstrate the high activity of the obtained sulfides for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).