Emerging high entropy metal sulphides and phosphides for electrochemical water splitting

Hydrogen is expected to be a major clean and renewable energy source in the coming decades. Numerous electrocatalysts, including noble metals, oxides, hydroxides, carbides, transition metal phosphides/sulfides, and graphene-based materials, have been studied to produce hydrogen efficiently. Nevertheless, the demand for electrocatalysts with desired catalytic activity and stability in the hydrogen evolution reaction and oxygen evolution reaction has been largely unmet. High-entropy metal sulfides/phosphides (HEMSs/Ps) are a new class of materials, in which at least five (or >5) different principal metal elements are deliberately incorporated into a homogeneous single-phase sulfide or phosphide structure and have received significant attention due to the highly active site densities and potential synergy between multiple elements toward electrocatalysis. Although limited examples are available for these emerging materials, recent studies have demonstrated the great potential of HEMSs/Ps in the energy material horizon. This highlight emphasizes the synthetic strategies, unique electrocatalytic properties, and challenges and perspectives of HEMS/P electrocatalysts.