B. Enright et al., SPECTROSCOPIC DETERMINATION OF FLAT-BAND POTENTIALS FOR POLYCRYSTALLINE TIO2 ELECTRODES IN MIXED-SOLVENT SYSTEMS, Journal of physical chemistry, 98(24), 1994, pp. 6195-6200
We report studies directed toward a quantitative understanding of the
relationship between the flatband potential (V-fb) of a metal oxide se
miconductor electrode (titanium dioxide) and the composition of a cont
iguous electrolyte solution (water, methanol, ethanol, and acetonitril
e each containing 0.2 mol dm(-3) tetrabutylammonium perchlorate). A re
lationship between V-fb and the proton-generating ability of the elect
rolyte solvent, as measured by the autoprotolysis constant of the pure
solvent, is demonstrated. Additional studies have examined the depend
ence of V-fb on the composition of a binary electrolyte solvent mixtur
e (acetonitrile/ethylene carbonate and acetonitrile/water). We conclud
e that the composition of the acetonitrile/ethylene carbonate mixture
at the semiconductor-electrolyte solution interface (SLI) is similar t
o that of the bulk solution. However, for an acetonitrile/water mixtur
e there is preferential adsorption of water at the SLI. Finally, for a
protic electrolyte solutions, the dependence of V-fb on the electrolyt
ic solute was studied. Cations such as Li+ and Na+ are potential deter
mining.