Morphology-Conserving Non-Kirkendall Anion Exchange of Metal Oxide Nanocrystals

Yongjun Lim, Chang Hee Lee, Chul Ho Jun, Kwanpyo Kim, Jinwoo Cheon

Research output: Contribution to journalArticle

Abstract

Nanoscale dynamic processes such as the diffusion of ions within solid-state structures are critical for understanding and tuning material properties in a wide range of areas, such as energy storage and conversion, catalysis, and optoelectronics. In the generation of new types of nanocrystals (NCs), diffusion-mediated ion exchange reactions have also been proposed as one of the most effective transformational strategies. However, retaining the original morphology and crystal structure of metal oxide NCs has been challenging because of Kirkendall void formation, and there has been no success, especially for anion exchange. Here we show that with the aid of an oxygen extracting reagent (OER), anion diffusion is dramatically accelerated and morphology-conserving anion exchange without Kirkendall void formation is possible. In the case of the conversion of Fe3O4 to Fe3S4, oxygen extraction and subsequent formation of the amorphous phase facilitate the migration of incoming sulfur anions by approximately 100-fold, which is close to the level of the outgoing cation diffusivity. We also demonstrate that the working principle of the morphology-conserving non-Kirkendall anion exchange is operative for metal oxide NCs with different shapes and crystal structures.

Original languageEnglish
Pages (from-to)9130-9134
Number of pages5
JournalJournal of the American Chemical Society
Volume142
Issue number20
DOIs
Publication statusPublished - 2020 May 20

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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