Synthesis of iron nanoparticle: Challenge to determine the limit of hydrogen reduction in supercritical water

Toshihiko Arita, Hidetsugu Hitaka, Kimitaka Minami, Takashi Naka, Tadafumi Adschiri

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Supercritical hydrothermal syntheses of metal nanoparticles were investigated. Organic metal salt and hydrogen gas produced by water catalyzed decomposition of formic acid was employed as metal sources and reduction agent, respectively. The formation of iron was verified by measuring the magnetic property of the products by superconducting quantum interference device (SQUID) magnetometer as well as crystallographic analysis by X-ray diffraction (XRD). As predicted by the free energy calculation of reduction of metal oxides by hydrogen molecule, silver, palladium, copper, nickel and cobalt nanoparticles were synthesized without using surface modifier, whereas, iron could be synthesized at small yield. The main product was iron oxides (mainly magnetite). In order to increase the yield of iron, hexanoic acid was employed as an in situ surface modifier of the synthesis. The surface modification lessened the size of the synthesized nanoparticles and increased the yield of iron. The optimum condition for iron synthesis was also investigated, as a result, 7.6% yield of iron was achieved.

Original languageEnglish
Pages (from-to)183-189
Number of pages7
JournalJournal of Supercritical Fluids
Issue number2
Publication statusPublished - 2011 Jun


  • Hydrogen reduction in water
  • Metal nanoparticle
  • Supercritical hydrothermal synthesis
  • Surface-modified nanoparticle
  • Water-gas shift reaction

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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