The influence of surface topography on the photocatalytic activity of electrophoretically deposited titanium dioxide thin films

Recently, titanium dioxide thin film coatings have received considerable attention due to their wide self-cleaning abilities with applications ranging from photocatalytic building cladding to vehicle anti-fogging mirrors. Traditionally, the photocatalytic coatings are deposited by dip, spin, spray and CVD methods which are suitable for flat substrates. For irregular conductive surfaces electrochemical means such as electrophoretic deposition (EPD) can be used. In this paper, we present the use of an EPD route to alter the surface morphology of nanocrystalline TiO₂ thin films. By modifying the initial particle sizes within the colloidal suspensions used during EPD, it was possible to produce particulate coatings with differing grains sizes and surface roughness. The influence of the surface topography on the photocatalytic activity of the film was investigated through ATR-FTIR analysis of the decomposition of stearic acid under ultraviolet irradiation. It was determined that surface topography such as grain size and roughness had a key impact in the film photocatalytic properties.