Continuous hydrothermal synthesis of ZnGa2O4:Mn 2+ nanoparticles at temperatures of 300-500 °c and pressures of 25-35 MPa

Hiromichi Hayashi, Atsuko Suino, Kenji Shimoyama, Masafumi Takesue, Suguru Tooyama, Richard L. Smith

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8 Citations (Scopus)


Mn2+ doped ZnGa2O4 particles were continuously synthesized in subcritical and supercritical water using a flow hydrothermal reaction system. Zn, Ga and Mn nitrates were used as the starting materials. The syntheses were carried out at temperatures from 300 to 500 °C, at pressures from 25 to 35 MPa, at KOH concentration of 0.04 M, and for residence times from 0.13 to 1.13 s. X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric differential thermal analysis (TG-DTA) and photoluminescent spectroscopy were used to characterize the samples. Single phase of ZnGa2O4 was achieved at residence times of less than 1 s. The crystallite sizes were in the range from 12 to 21 nm which tend to increase with an increase in the reaction temperature and with a decrease in the reaction pressure. Green emission was observed for the annealed samples under reducing conditions whereas as-synthesized samples did not exhibit photoluminescence.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalJournal of Supercritical Fluids
Publication statusPublished - 2013


  • Green phosphor
  • Hydrothermal synthesis
  • Mn doping
  • Supercritical water
  • Zinc gallate

ASJC Scopus subject areas

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


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