Silver Vanadium Oxide Nanomaterials: Controlled Synthesis by Hydrothermal Method and Efficient Photocatalytic Degradation of Atrazine and CV Dye

Silver vanadium oxides have received remarkable attention in recent years because of their stability, suitable band gaps, and relatively superior photocatalytic abilities. This study synthesizes silver vanadates by the hydrothermal method and investigates their photocatalytic abilities for removing crystal violet (CV) and atrazine pollutants under visible-light irradiation. The as-prepared silver vanadates are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). Crystal violet and atrazine could be successfully degraded in the presence of silver vanadate catalyst under visiblelight irradiation. The obtained results show complete degradation of crystal violet after 24 h, and over 97% of atrazine was degraded after 72 h of treatment. Moreover, the as-prepared silver vanadate materials show extremely high catalytic stability and maintain stable activity after three catalytic cycles. The scavenger study indicates that •O2− radicals are the main active species, while •OH and h+ play an assistant role in the degradation of CV and atrazine. Liquid chromatography coupled with electrospray ionization mass spectrometry is applied to the analysis of the samples coming from the photocatalytic degradation of CV and atrazine. Potential degradation pathways for atrazine are evaluated exhibiting two different degradation pathways including dechlorination-hydroxylation, alkylic-oxidationde- alkylation. The N-de-methylation of the CV dye takes place in a stepwise manner with the various N-de-methylated intermediate CV species. The excellent activity and photostability reveal that silver vanadate is a promising visiblelight- responsive photocatalyst for water and wastewater treatment.