Enhanced photocatalytic activity of TiO2/Ag2O heterostructures by optimizing the separation of electric charges. (August 2021)

• Record Type: Journal Article
• Authors: Xu, Wei; Tang, Heli; Zhou, Nan; Zhang, Qingyu; Peng, Bo; Shen, Yu
• Is Part Of: Vacuum. Volume 190(2021)
• Publication Date: 2021-08
• Subjects: Ag2O -- TiO2 -- Heterostructure -- Photocatalysis; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2021.110283
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Photodegradation of organic pollutants is becoming a promising technique of remediating environment. In this work, TiO2 /Ag2 O heterostructured films were fabricated by a method of abnormally oxidizing Ag films through reactive magnetron sputtering deposition of TiO2 . The substrate temperature and O2 pressure were found to have significant impacts on the oxidation of Ag films and the formation of Ag2 O. The TiO2 /Ag2 O 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 /Ag2 O heterostructured films and the best result in degrading methylene blue was obtained at TiO2 thickness of 37 nm. The photocatalytic mechanism of TiO2 /Ag2 O 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 /Ag2 O 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. Highlights: Low-oxygen pressure is necessary for fabrication of TiO2 /Ag2 O heterostructured films. Temperature of fabricating TiO2 /Ag2 O heterostructured films is lower than 70 °C. TiO2 thickness can be used to optimize the photocatalytic activity of TiO2 /Ag2 O films. New viewpoint is proposed for charge separation in metal-oxide heterostructures.