Porous titania thin films grown by anodic oxidation for hydrogen sensors

Porous titanium dioxide (Titania) thin films were grown by anodic oxidation using high purity (99.7%) titanium foil in a dilute sulphuric acid (1 M) medium. The anodization process was carried out for 30 minutes with 20 mA/cm(2) and 50 mA/cm(2) current densities. The samples were characterized by XRD, SEM, and AFM techniques. It was found that the grown porous titania films were less sensitive to 500 ppm hydrogen in air ambient below 300 degrees C; however, the sensitivity and response behavior of the film at 300 degrees C are very much dependent on the growth conditions. Particularly, the films grown at current density 50 mA/cm(2) and 1 M acid concentration exhibited the lowest response time of 151 sec at 300 degrees C.