Differences in adsorption behavior of N3 dye on flat and nanoporous TiO2 surfaces

► The adsorption of N3 dye on two types of TiO2 surfaces (rutile single crystals and nanocrystalline films) was studied. ► We found that much less N3 dye was adsorbed on the nanoporous surface than on the flat (single-crystal) surface. ► One possible model is that the effective pH in the nanopores is higher than that on the TiO2 surface.