Photocatalytic performance of porous TiO2 layers prepared by quantitative electrophoretic deposition from organic solvents

Highly-crystalline TiO2 nanoparticles coated on a suitable substrate make excellent photocatalysts for environmental applications. While electrophoretic deposition is frequently used to prepare such layers on a conductive support, this method often requires the presence of an additive to suppress nanoparticle agglomeration and increase particle surface charge. However, the presence of an additive can lead to contamination that negatively affects layer properties. To overcome this drawback, we developed an optimized electrophoretic method for the preparation of porous TiO2 layers, whose photocatalytic performance in the degradation of a toxic compound was analyzed. Our method enabled TiO2 layers (anatase, rutile and their mixture) to be quantitatively deposited on rigid substrates (stainless steel, FTO-glass and silicon wafers) without sintering and without the use of a dispersive additive. The photocatalytic performance of layers depended on the structural properties of titania particles, especially their allotropic form (anatase vs. rutile) and crystallinity, and on the presents of defects within the crystals. For well-developed crystals of anatase phase a high rate of the degradation of 4-chlorophenol and its almost complete mineralization were achieved. Owing to their excellent properties, especially stability and photocatalytic performance, the layers prepared by EPD are suitable for a broad range of environmental applications.