Noble-Metal High-Entropy-Alloy Nanoparticles: Atomic-Level Insight into the Electronic Structure

Dongshuang Wu, Kohei Kusada, Yusuke Nanba, Michihisa Koyama, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Okkyun Seo, Ibrahima Gueye, Jaemyung Kim, Loku Singgapulige Rosantha Kumara, Osami Sakata, Shogo Kawaguchi, Yoshiki Kubota, Hiroshi Kitagawa

Research output: Contribution to journalArticlepeer-review

92 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)3365-3369
Number of pages5
JournalJournal of the American Chemical Society
Volume144
Issue number8
DOIs
Publication statusPublished - Mar 2 2022

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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