Electrochemical, spectral, and quartz crystal microgravimetric assessment of conduction band edge energies for nanocrystalline zirconium dioxide/solution interfaces

Buford I. Lemon, Fang Liu, Joseph T. Hupp

Research output: Contribution to journalReview article

11 Citations (Scopus)

Abstract

Electrochemical quartz crystal microgravimetry studies of porous nanocrystalline ZrO2 electrodes in acetonitrile containing 1 M LiClO4 show that surface electronic states can be accessed at potentials as far positive as 0 V versus Ag/AgCl, as evidenced by uptake of charge-compensating cations. A much higher density of surface states is encountered beginning at about -1.3 V. Based on previous work with TiO 2, SnO2, and ZnO, this potential is tentatively identified with Ecb for ZrO2 and is about 0.5 V more negative than Ecb for TiO2. In water, cation uptake is replaced by efficient reduction of H3O+ or water to hydrogen, a finding that has interesting parallels in radiation chemistry. Identifying the onset potential for hydrogen evolution with either Ecb or a potential characteristic of a high density of trap states, the value obtained is about 0.3 V negative of Ecb for TiO2. Like the conduction band edge energy for titanium dioxide, the putative Ecb value for ZrO 2 shifts negatively with increasing pH. Comparisons of surface-based ligand-to-metal charge-transfer band energies point to an Ecb value for colloidal ZrO2 in water that is about 0.4 V negative of the value for colloidal TiO2. Consistent with three recent literature reports, empty states should lie low enough in energy to permit efficient injection from photoexcited dyes under certain conditions.

Original languageEnglish
Pages (from-to)1225-1230
Number of pages6
JournalCoordination Chemistry Reviews
Volume248
Issue number13-14
DOIs
Publication statusPublished - Jul 1 2004

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Keywords

  • Conduction band edge
  • Semiconductor
  • Zirconium dioxide

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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