Anodic TiO2 Thin Films: Photoelectrochemical, Electrochemical, and Structural Study of Heat‐Treated and Modified Films

Abstract

The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of deposited by thermal decomposition of on anodically grown films are examined. The anodic 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 into the film. Conversely, films grown at potential ramping rates of 0.1 mV/s had a structure which allowed to penetrate into the film along grain boundaries. Surface films of exhibited an electrocatalytic effect but also strongly reduced the photocurrent response. additions to the films which did penetrate the oxide acted as nonelectrocatalytically active species within the layer and had little effect on the photocurrent response of the oxide film. A model of distribution at the surface and along the grain boundaries of crystallites is considered.