High performance of Ag/BiVO₄ photocatalyst for 2,4-Dichlorophenoxyacetic acid degradation under visible light

With the aim of exploring and comparing the photocatalytic degradation of 2,4-Dichlorophenoxyacetic acid (2,4-D) under visible light, BiVO₄ was synthesized by using coprecipitation and hydrothermal methods and modified with silver nanoparticles (AgNP) employing a photo-deposition method. X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were some of the characterization techniques used. A particular synergy was observed when decorating the hydrothermally prepared BiVO₄ with AgNP, showing the higher degradation/mineralization of 2,4-D. According to the results, AgNP served as efficient co-catalysts of BiVO₄, allowing the electron separation/transfer to generate the OH radicals required for the reaction. A parallel pathway of 2,4-D photodegradation was proposed, including 2,4-Dichlorophenol and oxalic acid as the main intermediary compounds. Active species trapping experiments demonstrated that the photogenerated holes play a fundamental role in promoting both the direct oxidation of 2,4-D and generation of OH radicals.