High entropy materials (HEMs) have emerged as a promising class of materials for a variety of applications due to their unique structural properties, including high configurational entropy, lattice distortion, and sluggish diffusion. [1] These characteristics make HEMs especially attractive for electrocatalysis, where enhanced stability, tuneable active sites, and synergistic effects from multiple components can be exploited to improve catalytic performance.[2] In this study, we present the colloidal synthesis of high entropy Cu-Sb-Ni-Ag-Zn-S nanocrystals (NCs) using a cation exchange pathway, starting from a quaternary template and culminating in the formation of a single-phase high entropy material. The synthetic route begins with the preparation of a quaternary Cu-Zn-Sb-S template in the tetrahedrite phase. The tetrahedrite template, serves as an ideal platform due to its flexible crystal structure, which allows for the incorporation of multiple cations without significant disruption of the lattice. By leveraging a cation exchange process, we successfully incorporate additional transition metal cations—namely, Ni and Ag—into the quaternary structure through the simultaneous injection of these metal precursors. This stepwise inclusion of guest cations is facilitated by the relatively soft nature of the Cu–S bonds in tetrahedrite, which enables facile substitution and diffusion of cations. The result is the formation of a homogeneous, single-phase Cu-Sb-Ni-Ag-Zn-S NC with a high entropy configuration. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses confirm the crystallinity and uniformity of the NCs, with no discernible phase segregation or formation of secondary phases. Elemental maps obtained via Energy-dispersive X-ray spectroscopy (EDS) further verifies the presence of all constituent elements (Cu, Sb, Ni, Ag, Zn, and S) and scanning electron microscope (SEM) EDS is used to estimate the atomic % of each element within the NCs, confirming the successful formation of a high entropy material.

The high entropy nature of the material is expected to enhance the hydrogen evolution reaction (HER) activity due to several factors that includes increased surface area and active sites resulting from the nanoscale size of the crystals, synergistic effects between the different metal cations, and improved stability under reaction conditions due to the structural robustness imparted by the high entropy configuration. Therefore, in this work, we further test the electrocatalytic activity of the synthesized Cu-Sb-Ni-Ag-Zn-S NCs for HER. Preliminary electrochemical measurements indicate that the high entropy Cu-Sb-Ni-Ag-Zn-S NCs exhibit promising catalytic performance, with a low overpotential and high current density in HER. The stability of the NCs under acidic conditions further underscores their potential as robust electrocatalysts for practical applications. Thus, the resulting material represents a novel class of high entropy sulphide NCs that exhibit promising electrocatalytic activity for HER. This approach provides a versatile platform for the design of advanced HEMs with tuneable properties for a wide range of applications in catalysis.