Mott-Schottky Plots and Flatband Potentials for Single Crystal Rutile Electrodes

Ideal Mott-Schottky plots were obtained for TiO₂ single crystal electrodes after a special surface preparation procedure. Precise flatband potentials were determined as a function of pH for three different types of TiO₂ boules; significant differences between boules were observed. These differences were reflected in corresponding differences in the electrode potential for the onset of anodic photocurrent. Surface treatments that produced linear Mott-Schottky plots but with frequency dispersion results in apparent flatband potentials that did not correlate with the potential for the onset of anodic photocurrent. Ideal Mott-Schottky behavior could only be obtained for the specially prepared crystals if the electrolyte concentration was greater than 0.25M.