Preparation and ion diffusion performance of the nanoporous TiO2 coating through vacuum cold spray

Nanoporous TiO coating was an important part in the photoanode for dye sensitized solar cell. The cell photocurrent may be limited by the ion diffusion through the porous TiO coating. In this study, nanoporous TiO coating was deposited by vacuum cold spray using TiO powders in different primary particle size as feedstock. The porosity and pore size were examined by nitrogen adsorption and desorption technique. The diffusion performance of I in acetonitrile was investigated. The results showed that the pore size of the coating was significantly influenced by primary particle size. However, the porosity of the coatings was found to be the same despite different powders in different primary particle sizes. The I ion diffusion coefficient was found to increase with the increase of the pore size from 16 to 32 nm. A novel approach to enhance the ion diffusion performance of porous coating was proposed by controlling of the pore size within the porous coating deposited through vacuum cold spray