Photocatalytic activity of nitrogen-substituted TiO2 deposited with Pt and Ru

In this work, Pt- and Ru-deposited, nitrogen-substituted TiO2 were prepared and characterized by the discoloration of MB and H2 evolution. The characteristics were evaluated in terms of methylene blue (MB) discoloration, open circuit voltage (OCV), photocurrent (I ph ), and hydrogen production. First, the Pt-deposited TiON revealed comparable activity in MB discoloration, while both TiONs resulted in somewhat less activity than P25. Second, an external bias was systematically applied to electrodes made of the prepared samples, resulting in −0.41∼0.51 OCV, −400∼400 μA and noticeable hydrogen evolution above 300 μA in absolute value when a bias of −1.5∼1.5 V was applied to the working electrode of P25. The electrolyte and light intensity affected the light-responsive characteristics of the photocatalysts, confirming the relationship between OCV, I ph and H2 and that metal deposition slightly inhibited the I ph and H2 evolution while Ru-deposited TiON did not degrade MB effectively.