Effect of Cathodic Polarization of n-TiO_2 Thin Films on Their Photoresponse towards Water Splitting Reactions

Cathodic reduction of Titanium oxide (n-TiO_2) thin films was investigated as an alternative approach to customary hydrogen modification of n-TiO_2 under hydrogen gas stream at high temperature. Hydrogen modification of n-TiO_2 was carried out electrochemically under cathodic polarization. The photo-response of the electrochemically hydrogen modified n-TiO_2 (HM-n-TiO_2) exhibited a four-fold enhancement in their photoresponse compared to n-TiO_2 during water splitting under solar simulated light. The photoactivity of HM-n-TiO_2 suffers a substantial decrease after heat-treatment at 200°C, remarkably the photoactivity of these samples was fully repaired after re-hydrogenation under similar conditions. The electrodes were characterized using electrochemical and spectroscopic techniques