Wu Dongshuang, Kusada Kohei, Nanba Yusuke, Koyama Michihisa, Yamamoto Tomokazu, Toriyama Takaaki, Matsumura Syo, Seo Okkyun, Gueye Ibrahima, Kim Jaemyung, Rosantha Kumara Loku Singgapulige, Sakata Osami, Kawaguchi Shogo, Kubota Yoshiki, Kitagawa Hiroshi
Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
The HAKUBI Center for Advanced Research, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
J Am Chem Soc. 2022 Mar 2;144(8):3365-3369. doi: 10.1021/jacs.1c13616. Epub 2022 Feb 15.
The compositional space of high-entropy-alloy nanoparticles (HEA NPs) significantly expands the diversity of the materials library. Every atom in HEA NPs has a different elemental coordination environment, which requires knowledge of the local electronic structure at an atomic level. However, such structure has not been disclosed experimentally or theoretically. We synthesized HEA NPs composed of all eight noble-metal-group elements (NM-HEA) for the first time. Their electronic structure was revealed by hard X-ray photoelectron spectroscopy and density function theory calculations with NP models. The NM-HEA NPs have a lower degeneracy in energy level compared with the monometallic NPs, which is a common feature of HEA NPs. The local density of states (LDOS) of every surface atom was first revealed. Some atoms of the same constituent element in HEA NPs have different LDOS profiles, whereas atoms of other elements have similar LDOS profiles. In other words, one atom in HEA loses its elemental identity and it may be possible to create an ideal LDOS by adjusting the neighboring atoms. The tendency of the electronic structure change was shown by supervised learning. The NM-HEA NPs showed 10.8-times higher intrinsic activity for hydrogen evolution reaction than commercial Pt/C, which is one of the best catalysts.
高熵合金纳米颗粒（HEA NPs）的组成空间显著扩展了材料库的多样性。HEA NPs中的每个原子都具有不同的元素配位环境，这需要在原子水平上了解局部电子结构。然而，这种结构尚未在实验或理论上被揭示。我们首次合成了由所有八种贵金属族元素组成的HEA NPs（NM-HEA）。通过硬X射线光电子能谱和使用NP模型的密度泛函理论计算揭示了它们的电子结构。与单金属纳米颗粒相比，NM-HEA NPs的能级简并度更低，这是HEA NPs的一个共同特征。首次揭示了每个表面原子的局域态密度（LDOS）。HEA NPs中一些相同组成元素的原子具有不同的LDOS分布，而其他元素的原子具有相似的LDOS分布。换句话说，HEA中的一个原子失去了其元素特性，并且有可能通过调整相邻原子来创建理想的LDOS。通过监督学习展示了电子结构变化的趋势。NM-HEA NPs对析氢反应的本征活性比商业Pt/C（最好的催化剂之一）高10.8倍。
