Facile one-step sonochemical synthesis of AgCl quantum dots with enhanced photocatalytic activity and its size effects

In this work, a facile ultrasonic method for the fabrication of AgCl quantum dots (AgCl QDs) with an average diameter of about 2.5 nm was reported for the first time. The material was analyzed by various techniques. In addition, effects of material's size on its photocatalytic activities were studied. Results suggested that the AgCl QDs exhibited excellent photocatalytic activity to degrade Rhodamine B (RhB) and tetracycline (TC) under visible light illumination, and the degradation rate of RhB (TC) had reached up to 96.6% (72.2%) in 20 min, which was higher than that of AgCl nanoparticles (23 nm) and AgCl nanospheres (114 nm), respectively. Besides, the band gap of the material was increased when the size of material decreased from 23 nm to 2.5 nm. The significantly improved photocatalytic performance and increased band gap of AgCl QDs were mainly related to the quantum size effects of AgCl, which results in the more electron fluctuation in quantized energy levels and the lower recombination of electrons and holes.