McCormick Connor R, Schaak Raymond E
J Am Chem Soc. 2021 Jan 20;143(2):1017-1023. doi: 10.1021/jacs.0c11384. Epub 2021 Jan 6.
High entropy materials, which contain a large number of randomly distributed elements, have unique catalytic, electrochemical, and mechanical properties. The high configurational entropy of the randomized elements drives the formation of high entropy materials; therefore, high temperatures and quenching are typically required to stabilize them. Because of this, colloidal nanoparticles of high entropy materials are difficult to synthesize and remain rare, despite their desirable high surface areas and solution dispersibilities. Here, we introduce simultaneous multication exchange as an alternative low-temperature pathway to colloidal nanoparticles of high entropy materials. Roxbyite CuS nanoparticles react with a substoichiometric mixture of Zn, Co, In, and Ga to produce nanoparticles of the high entropy metal sulfide ZnCoCuInGaS. The ZnCoCuInGaS nanoparticles are thermally stable, and exchange reactions using fewer cations do not produce the high entropy phase. The use of colloidal nanoparticle cation exchange as a synthetic platform provides both entropic and enthalpic driving forces that, in addition to configurational entropy, enable the formation of high entropy phases at solution-accessible temperatures.
高熵材料包含大量随机分布的元素，具有独特的催化、电化学和机械性能。随机元素的高组态熵驱动了高熵材料的形成；因此，通常需要高温和淬火来使其稳定。正因如此，高熵材料的胶体纳米颗粒难以合成且仍然稀少，尽管它们具有理想的高比表面积和溶液分散性。在此，我们引入同步多阳离子交换作为一种替代的低温途径来制备高熵材料的胶体纳米颗粒。罗克斯比矿硫化铜纳米颗粒与锌、钴、铟和镓的亚化学计量混合物反应，生成高熵金属硫化物ZnCoCuInGaS的纳米颗粒。ZnCoCuInGaS纳米颗粒具有热稳定性，使用较少阳离子的交换反应不会产生高熵相。使用胶体纳米颗粒阳离子交换作为合成平台提供了熵和焓驱动力，除了组态熵之外，还能在溶液可达的温度下形成高熵相。
