Amine functionalized reduced graphene oxide decorated with BiOI and Ag3PO4 as a Novel Visible Light catalyst against RhB

Bismuth-based structures are recognized as active photocatalysts against emerging contaminants such as organic dyes. However, the pure form of semiconductors needs modification to improve characteristics such as photo reactivity and catalytic performance. In this context, a novel heterojunction comprising BiOI, amine-functionalized reduced graphene oxide (rGO), and Ag₃PO₄ was prepared which led to a reduction in energy bandgap and electron-hole recombination rate. Additionally, amine functionalization enhances catalytic performance of ArGO@BiOI photocatalyst against rhodamine B (RhB). The photocatalytic performance of BiOI, ArGO@BiOI, and ArGO@BiOI@Ag₃PO₄ composites for RhB was observed to be 92.25, 92.57, and 99.40% after 35 min, respectively. Optimizing RhB removal process by response surface methodology (RSM), indicated that the highest removal of ~ 99% was achieved at a catalyst dose = 620 mg/L, pH = 5.4, RhB = 5 mg/L, and irradiation time = 35 min. The catalytic performance was demonstrated on real water matrix samples, which revealed a significant removal of 89.76%- 98.29%. The kinetics of RhB abatement obeyed the first-order model, where the rate constant increases as the dye level decrease (0.074-0.114 min^-1). Furthermore, the rate constant of first-order kinetic model under sunlight was ~ 7.5 times faster than LED light. Radical trapping tests indicated the vital role of electrons in RhB removal process. ArGO@BiOI@Ag₃PO₄ maintained its photocatalytic efficiency over four cycles, with dye removal observed in the range of 99.40-71.4%.