Construction of Ag/Bi7O9I3 Catalyst for Photocatalytic Degradation of Rhodamine B

In this work, we fabricated an Ag/Bi₇O₉I₃ composite and tested the composite for the photodegradation of Rhodamine B (RhB) dye under UV–vis light irradiation. XRD, FESEM, TEM, UV–visible absorbance, XPS studies, ESR, and electrochemical analysis were used to characterize the synthesized photocatalysts. The synthesized catalyst displayed a maximum degradation efficiency of 98.45% in the 150-min experiment, which is nearly 1.56 times higher than Bi₇O₉I₃. The enhanced photocatalytic activity of Ag/Bi₇O₉I₃ is attributed to the acceleration of charge separation and transfer of charge carriers with the inclusion of Ag. The improvement in photocatalytic efficiency of Ag/Bi₇O₉I₃ can be attributed to Ag deposition, which acts as an electron sink to avoid recombination of photogenerated electrons and holes. Additionally, Ag nanoparticles may show plasmonic resonance producing more electron–hole pairs in Bi₇O₉I₃. Furthermore, a variety of tests were carried out on Ag/Bi₇O₉I₃ in order to clarify how different factors affect the photodegradation efficiency. The medium with pH = 3, catalyst loading = 35 mg, and Rhodamine B concentration = 10 ppm resulted in highest activity. Using a radical scavenging experiment and ESR studies, the effective radicals in promoting dye degradation have been identified, and ·O₂⁻ radicals turned out to be the main radicals in promoting photocatalysis. Additionally, the reusability and degradation mechanisms of the enhanced photodegradation on the specified photocatalyst were examined.