Calorimetric Measurements of Surface Energy of Amorphous HfO2 Nanoparticles Produced by Gas Phase Condensation

Geetu Sharma, Sergey V. Ushakov, Hui Li, Ricardo H.R. Castro, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Thermodynamics of nanomaterials is strongly influenced by the energetic contribution from atoms located at the interfaces. Therefore, accurately assessing the surface energy of nanomaterials is essential for calculating and predicting thermodynamic properties. In the present work, surface energy of amorphous hafnium oxide (am-HfO2) nanoparticles was measured using independent calorimetric techniques. am-HfO2 nanoparticles were synthesized by condensation from a gas phase generated through laser evaporation of bulk HfO2 targets at 0.1 Torr oxygen pressure. Their surface energy was directly measured using high-temperature oxide melt solution calorimetry, differential scanning calorimetry, and water adsorption calorimetry. The measured surface energies using the above techniques, respectively, are 0.76 ± 0.12, 0.47 ± 0.2, and 0.59 ± 0.1 J/m2. The differences among the surface energy values are about 0.3 J/m2, which is generally within the experimental uncertainties and different assumptions for each technique. The surface energy of the amorphous phase is substantially smaller than that of crystalline phases, as seen previously for other oxides. Thus, the amorphous phase may be thermodynamically favored when small particles are produced and retained.

Original languageEnglish (US)
Pages (from-to)10392-10397
Number of pages6
JournalJournal of Physical Chemistry C
Volume121
Issue number19
DOIs
StatePublished - May 18 2017
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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