Synthesis of high surface area TiO2 coatings on stainless steel by electrophoretic deposition

Large surface area, homogenous, and adhesive TiO2 coatings on stainless steel substrates were prepared by electrophoretic deposition (EPD) of colloidal dispersions of TiO2 nanoparticles in water and ethanol. Several chemical additives were used to optimize the deposition process. The best results were obtained for dispersions in water containing a mixture of Tiron and Pluronic (R) F127, which gave homogeneous layers, showing excellent adhesion and a large BET surface area, close to 200 m(2)/g. Ethanol dispersions also gave much adhesive coatings when poly(acrylic acid) was used as an additive. Nevertheless, their thickness was lower, and their surface area was less than 100 m(2)/g. We have shown that water splitting, occurring in the aqueous sol during the EPD, led to deposited masses lower than those expected from the Hamaker law. However, the electrolysis of water and also the small cracks in the coatings had no detrimental effects on adhesion.