Engineering High-Entropy Tetrahedrite Cu–Zn–Sb–Ag–Bi–S Nanocrystals via Sequential Cation Exchange as Efficient Catalysts for Hydrogen Evolution Reactions

High-entropy chalcogenides represent an emerging class of functional materials with immense potential in broad applications. To date, colloidal high-entropy nanocrystals (NCs) have predominantly been accessed via co-nucleation of precursors or simultaneous incorporation of multiple cations. While effective, these approaches lack a mechanistic understanding of NC synthesis. Here, we report the colloidal synthesis of high-entropy Cu–Zn–Sb–Ag–Bi–S NCs in the tetrahedrite phase, employing a sequential, low-temperature cation-exchange strategy, starting from a Cu–Zn–Sb–S tetrahedrite template. Subsequent sequential cation exchanges preserve the crystal phase while enabling precise control over morphology. This bottom-up approach circumvents the need for high-temperature synthesis, while allowing isolation and characterization of intermediate states, providing important mechanistic insight into the evolution of high-entropy NCs. The nanocrystals served as hydrogen evolution reaction electrocatalysts with less negative cathodic potentials. This work introduces the high-entropy tetrahedrite phase, paving the way for entropy-stabilized chalcogenides for energy conversion applications.