Electronic, energetic, and chemical effects of intrinsic defects and Fe-doping of CoAl2O4: A DFT+U study

Aron Walsh, Y F Yan, M M Al-Jassim, S H Wei

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66 Citations (Scopus)

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 Fe-doping 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 languageEnglish
Pages (from-to)12044-12050
Number of pages7
JournalJournal of Physical Chemistry C
Volume112
Issue number31
DOIs
Publication statusPublished - 2008

Keywords

  • sol-gel
  • surface
  • photoelectrolysis
  • semiconductors
  • basis-set
  • oxides
  • spinel
  • cation distribution
  • augmented-wave method
  • diffraction

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