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 language | English |
|---|---|
| Pages (from-to) | 1225-1230 |
| Number of pages | 6 |
| Journal | Coordination Chemistry Reviews |
| Volume | 248 |
| Issue number | 13-14 |
| DOIs | |
| Publication status | Published - Jul 2004 |
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Keywords
- Conduction band edge
- Semiconductor
- Zirconium dioxide
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
Cite this
Electrochemical, spectral, and quartz crystal microgravimetric assessment of conduction band edge energies for nanocrystalline zirconium dioxide/solution interfaces. / Lemon, Buford I.; Liu, Fang; Hupp, Joseph T.
In: Coordination Chemistry Reviews, Vol. 248, No. 13-14, 07.2004, p. 1225-1230.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Electrochemical, spectral, and quartz crystal microgravimetric assessment of conduction band edge energies for nanocrystalline zirconium dioxide/solution interfaces
AU - Lemon, Buford I.
AU - Liu, Fang
AU - Hupp, Joseph T
PY - 2004/7
Y1 - 2004/7
N2 - 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.
AB - 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.
KW - Conduction band edge
KW - Semiconductor
KW - Zirconium dioxide
UR - http://www.scopus.com/inward/record.url?scp=4644285567&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4644285567&partnerID=8YFLogxK
U2 - 10.1016/j.ccr.2004.03.004
DO - 10.1016/j.ccr.2004.03.004
M3 - Article
VL - 248
SP - 1225
EP - 1230
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
SN - 0010-8545
IS - 13-14
ER -