Tuning of BixOyCl formation with sonication time during ultrasound-hydrothermal preparation

Developing novel and visible-light drive photocatalysts is a hot topic, and bismuth oxychloride is one of the popular photocatalysts. In this paper, a series of bismuth oxychloride were synthesized by ultrasonic-hydrothermal method with different ultrasonic time. By simply changing the ultrasonic time, we can control the morphology, structure, stoichiometry and photoelectric performance of bismuth oxychloride. The possible mechanism for the formation of BixOyCl photocatalysts involved the ultrasonic destruction of chemical bonds and increase of oxygen vacancy concentration, and the influence of ultrasonic on the pH during preparation. The sample of ultrasonic 30 min (U-30) showed the best photocatalytic activity due to the suitable morphology, structure, photoelectric performance, the formation of the heterostructure, and the presence of oxygen vacancies. For the removal of Rhodamine B (/Ciprofloxacin), the reaction rate constant for U-30 was 10.4 (/3.6), 4.9 (11.6), 6.9 (/4.8), and 9.3 (/2.3) times that of the U-0, U-10, U-20, and U-40, respectively. Photoluminescence spectra showed that the photogenerated electron-hole recombination rate decreased gradually with the ultrasonic time. Further, the possible mechanism of photocatalytic process was investigated. This research provides a green, economical and simple method to modify bismuth oxychloride. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.