Synergic effect of oxygen vacancy defect and shape on the photocatalytic performance of nanostructured TiO2 coating

In the present work TiO2 coatings with different level of oxygen vacancy defect and different shapes of nanosphere, nanocube, and nanopyramid were deposited on glass substrate by modified ultrasonic spray pyrolysis method. The prepared coatings were successfully used for the photocatalytic degradation of paraoxon pesticide under visible light irradiation. Based on the obtained results, among the papered coatings, the TiO2 coating with nanopyramidal shape and oxygen vacancy defect has the highest photocatalytic activity, and the lowest photocatalytic activity was observed in the case of the TiO2 coating with nanospherical shape and without oxygen vacancy defect. The reason for these results is the sharp edges and corners of nanopyramid which decreases the electron-hole recombination rate. Furthermore, presence of oxygen vacancy defect improve the visible light photocatalytic activity via narrowing the band gap energy and separation of the electron-hole. (C) 2019 Elsevier Ltd. All rights reserved.