Sonochemical Fabrication of S-Scheme AgI/g-C3N4 Heterojunction for Efficient Photocatalytic Degradation of RhB Dye.

This research work demonstrates a highly efficient photocatalytic destruction of rhodamine B dye and tetracycline drug on the surface of S-scheme AgI/g-C₃N₄ heterojunctions under simulated solar radiations. The thermal decomposition of urea fabricates g-C₃N₄ nanosheets with auspicious physicochemical and photocatalytic properties. However, brilliant yellow AgI nanoparticles are synthesized by combined precipitation-ultrasonic routes. AgI/g-C₃N₄ heterojunctions containing different compositions of g-C₃N₄ and AgI nanoparticles are constructed sonochemically. The physicochemical properties of the heterojunctions are investigated by DRS, PL, HRTEM, Zeta potential measurements, BET, XPS and XRD analysis. The photocatalytic experiments have pointed out that g-C₃N₄ sheets decomposes 12% of RhB dye due to the poor separation efficiency of the electron-hole pairs and low surface area of solid specimen. With introducing AgI nanoparticles on g-C₃N₄ sheets, the surface properties of the photocatalyst improved and the ultra-fast recombination rate of the electron-hole pairs is inhibited. The decomposition of RhB dye approaches 67, 92 and 85% of initial dye concentration for heterojunctions containing 5, 10 and 15 wt% AgI, respectively. Superoxide, positive holes and hydroxyl radicals are the main reactive species for expelling RhB as elucidated from scrubber experiments. S-scheme charge transportation mechanism records a plausible explanation for production of charge carriers with auspicious redox power. Hopefully, this research study inspire the rational design of the photocatalysts for efficient destruction of organic pollutants. [ABSTRACT FROM AUTHOR]