Low temperature heat capacity of bulk and nanophase ZnO and Zn 1-xCoxO wurtzite phases

Chengcheng Ma, Quan Shi, Brian F. Woodfield, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The low temperature heat capacity of the ZnO-CoO solid solution system was measured from 2 to 300 K using the heat capacity option of a Quantum Design Physical Property Measurement System (PPMS). The thermodynamic functions in this temperature range were derived by curve fitting. The standard entropies of bulk ZnO and bulk ZnO-CoO (wurtzite, 18 mol% CoO) at T = 298.15 K were calculated to be (43.1 ± 0.4) J · mol-1 · K-1 and (45.2 ± 0.5) J · mol-1 · K-1, respectively. The surface entropy of ZnO was evaluated to be (0.02 ± 0.01) mJ · K-1 · m-2, which is essentially zero. No sharp magnetic transitions were observed in the solid solution samples. The nanophase solid solution, 12 mol% CoO, appears to bind H2O on its surface more strongly than ZnO.

Original languageEnglish (US)
Pages (from-to)191-196
Number of pages6
JournalJournal of Chemical Thermodynamics
Volume60
DOIs
StatePublished - 2013
Externally publishedYes

Keywords

  • Heat capacity
  • Nanoparticles
  • PPMS
  • Surface entropy
  • ZnO-CoO

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Physical and Theoretical Chemistry

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