The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of RuO2 deposited by thermal decomposition of RuCl3 on anodically grown TiO2 films are examined. The anodic TiO2 films, characterized by electron diffraction before and after thermal treatment, were found to be polycrystalline rutile. Anodic films grown by potential step polarization did not allow penetration of RuO2 into the film. Conversely, TiO2 films grown at potential ramping rates of 0.1 mV/s had a structure which allowed RuO2 to penetrate into the film along TiO2 grain boundaries. Surface films of RuO2 exhibited an electrocatalytic effect but also strongly reduced the photocurrent response. RuO2 additions to the films which did penetrate the oxide acted as nonelectrocatalytically active species within the TiO2 layer and had little effect on the photocurrent response of the oxide film. A model of RuO2 distribution at the surface and along the grain boundaries of TiO2 crystallites is considered.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of the Electrochemical Society|
|State||Published - Feb 1 1989|