Electronic, Energetic and Chemical Effects of Intrinsic Defects and Fe-Doping of CoAl2O4: A DFT+U Study

Aron Walsh, Yanfa Yan, M. M. Al-Jassim, Su Huai Wei

Research output: Contribution to journalArticlepeer-review

81 Scopus Citations

Abstract

The spinel cobalt aluminate has gained interest as a potential photoelectrochemical catalyst for the renewable production of hydrogen. Using band structure theory, we determine the energetics of possible intrinsic point defects in spinel CoAl2O4 and analyze their effect on its electronic and chemical properties. Extrinsic Fedoping is also examined. Cation vacancies are found to be shallow acceptors, but their formation energy is sensitive to the growth conditions; an oxygen rich environment is required to enhance the p-type conductivity. Fe is an isovalent substituent on the Co (Al) site, exhibiting a preference for octahedral coordination, and forms a deep donor (acceptor) level near the center of the band gap, corresponding to a Fe(II) to Fe(III) transition.

Original languageAmerican English
Pages (from-to)12044-12050
Number of pages7
JournalJournal of Physical Chemistry C
Volume112
Issue number31
DOIs
StatePublished - 7 Aug 2008

NREL Publication Number

  • NREL/JA-520-42582

Keywords

  • density functional theory
  • hydrogen production
  • spinel
  • transition metal oxides

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