Effects of Inorganic Acid Modification on Photocatalytic Performance of TiO and Its Activity-Enhanced Mechanism Related to Adsorbed O.

In this work, commercial P25 TiO is modulated by post-treatments with different acidic substances, and the effects of residual acidic substances on the photogenerated charge separation of TiO and its photocatalytic activity are investigated in detail. It is demonstrated by means of atmosphere-controlled surface photovoltage spectroscopy that an increase in acid surface modification is favorable for improving the photogenerated charge separation of TiO . As a result, its photocatalytic activity for the degradation of gas-phase acetaldehyde is enhanced greatly. On the basis of measurements of O temperature-programmed desorption of untreated and treated TiO , it is confirmed that an increased amount of acid surface modification promotes the adsorption of O on TiO . Hence, it is suggested for the first time that an increase in surface acidity through post-treatment with an appropriate amount of acidic substance leads to a clear enhancement of the photocatalytic activity of TiO by promoting O adsorption, and thus, improving the photogenerated charge separation of TiO . This work provides a feasible route for the synthesis of high-activity oxide-based semiconductor photocatalysts through surface modification with stable inorganic acids.