CaMoO4 mesocrystals with sonocatalytic activity for Rhodamine b removal

Abstract

In this paper, Calcium molybdate (CaMoO4) mesocrystals were prepared by the microwave-assisted hydrothermal method, and their sonocatalytic activity was explored by observing the removal of the dye Rhodamine B (RhB). X-ray diffraction confirmed the tetragonal scheelite-type structure, and micrographs revealed mesocrystals formed by nanograins with an average diameter of ∼ 100 nm. The band gap energy was estimated at ∼ 4.31 eV with the presence of an intermediate energy level of ∼ 3.98 eV. Photoluminescence spectra indicated broadband emission with green and orange contributions. It was demonstrated that the addition of the sonocatalyst induced ∼ 60 % dye removal in 120 min, under ultrasonic waves (40 kHz, 120 W). The sonocatalytic reaction was primarily driven by hydroxyl radicals as the main active species. In addition, the CaMoO4 mesocrystals exhibited excellent reusability, proving to be a potential sonocatalyst for water purification applications.