Acceleration effects of phosphate modification on the decay dynamics of photo-generated electrons of TiO2 and its photocatalytic activity

The surface modification with a proper amount of phosphate accelerates the dynamic decay of photogenerated electrons in the nanocrystalline anatase TiO2 film in the presence of O-2, consequently prolonging greatly the lifetime of photogenerated holes so as to improve the charge separation of TiO2 and then its photocatalytic activity for degrading gas-phase acetaldehyde and liquid-phase phenol mainly based on the transient absorption spectra and the measurements of electrochemical O-2 reduction and the produced hydroxyl radical amount. The acceleration effects are attributed to the increased amount of adsorbed O-2 by means of the curves of O-2 temperature-programmed desorption.