pH sensors based in TiO 2 NTs arrays

pH sensor fabricated with TiO2 nanotube arrays with diameter and length controlled by the anodization voltage and time were obtained and characterized. The TiO2 nanotube arrays were obtained by Ti foil anodization in a NH4F organic solution with 20 and 40 V for 5, 15 and 25 min. pH sensors based on TiO2 NTs electrodes presented linear response respect to the pH value in the 4 - 10 pH range. The pH sensor with nanotubes obtained with 20V / 25 min presents a reproducible response and the best sensitivity value, 45.8 mV/pH. This TiO2 NTs pH sensor irradiated by UV shows a very stable response and a sensitivity value of 50.9 mV/pH, close to Nernst equation (59 mV/pH).