Enhanced photocatalytic activity of TiO2/Ag2O heterostructures by optimizing the separation of electric charges

Photodegradation of organic pollutants is becoming a promising technique of remediating environment. In this work, TiO2/Ag2O heterostructured films were fabricated by a method of abnormally oxidizing Ag films through reactive magnetron sputtering deposition of TiO2. The substrate temperature and O-2 pressure were found to have significant impacts on the oxidation of Ag films and the formation of Ag2O. The TiO2/Ag2O heterostructured films fabricated under the conditions of low temperature and low-oxygen pressure exhibited excellent photocatalytic activity under irradiation of ultraviolet and visible light. The thickness of TiO2 layer was substantiated to be important in optimizing photocatalytic activity of TiO2/Ag2O heterostructured films and the best result in degrading methylene blue was obtained at TiO2 thickness of 37 nm. The photocatalytic mechanism of TiO2/Ag2O heterostructured films was discussed and the enhanced photocatalytic activity was attributed to the separation of electron-hole pairs, which is basically determined by the band structure in the heterostructures. This work provides an effective method of fabricating TiO2/Ag2O heterostructured films and are easily scaled up in industry. The suggested photocatalytic mechanism is helpful for comprehensively understanding the enhancement of photocatalytic activity observed in various forms of metal-oxide heterostructures.

Automated summary

This study fabricated TiO2/Ag2O heterostructured films using a unique method, which showed excellent photocatalytic activity under low temperature and low oxygen pressure conditions. The thickness of the TiO2 layer was found to significantly impact the photocatalytic performance, with enhanced activity attributed to the separation of electron-hole pairs.