Orientation dependence of charge-transfer processes on TiO{sub 2} (anatase) single crystals
Electrochemical measurements in aqueous and aprotic media have been carried out on anatase single crystal with exposed (101) and (001) surfaces, respectively. Water reduction and photo-oxidation take place at more negative potentials for the (001) surface than for the (101) surface. This can be rationalized in terms of a more negative flatband potential (by ca. 0.06 V) for the (001) face, which is due to dissociative chemisorption of water molecules on this surface. Lithium insertion is favored on the (001) surface, as evidenced by a higher standard rate constant for charge transfer (10{sup {minus}8} vs. 2{center_dot}10{sup {minus}9} cm/s) and a higher chemical diffusion coefficient for Li{sup +} insertion (4{center_dot}10{sup {minus}13} vs. 2{center_dot}10{sup {minus}13} cm{sup 2}/s) for the propagation along the c axis. This can be explained by a more open structure of the anatase lattice in this direction.
- Research Organization:
- Swiss Federal Inst. of Tech., Lausanne (CH)
- OSTI ID:
- 20075619
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 4 Vol. 147; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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