Non-oxidized bare copper nanoparticles with surface excess electrons in air

Kyungwha Chung, Joonho Bang, Athira Thacharon, Hyun Yong Song, Se Hwang Kang, Woo Sung Jang, Neha Dhull, Dinesh Thapa, C. Muhammed Ajmal, Bumsub Song, Sung Gyu Lee, Zhen Wang, Albina Jetybayeva, Seungbum Hong, Kyu Hyoung Lee, Eun Jin Cho, Seunghyun Baik, Sang Ho Oh, Young Min Kim, Young Hee LeeSeong Gon Kim, Sung Wng Kim

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


Copper (Cu) nanoparticles (NPs) have received extensive interest owing to their advantageous properties compared with their bulk counterparts. Although the natural oxidation of Cu NPs can be alleviated by passivating the surfaces with additional moieties, obtaining non-oxidized bare Cu NPs in air remains challenging. Here we report that bare Cu NPs with surface excess electrons retain their non-oxidized state over several months in ambient air. Cu NPs grown on an electride support with excellent electron transfer ability are encapsulated by the surface-accumulated excess electrons, exhibiting an ultralow work function of ~3.2 eV. Atomic-scale structural and chemical analyses confirm the absence of Cu oxide moiety at the outermost surface of air-exposed bare Cu NPs. Theoretical energetics clarify that the surface-accumulated excess electrons suppress the oxygen adsorption and consequently prohibit the infiltration of oxygen into the Cu lattice, provoking the endothermic reaction for oxidation process. Our results will further stimulate the practical use of metal NPs in versatile applications.

Original languageEnglish
Pages (from-to)285-291
Number of pages7
JournalNature Nanotechnology
Issue number3
Publication statusPublished - 2022 Mar

Bibliographical note

Publisher Copyright:
© 2022, The Author(s).

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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