Quercetin-sensitized BiOF nanostructures: An investigation on photoinduced charge transfer and regeneration process for degradation of organic for pollutants

In the present work, a non-toxic and economical route was employed for the synthesis of BiOF using Azadirachta indica plant (A.I.) leaf extract (BiOF-P) and its flavonoid constituent i.e. quercetin (BiOF-Q) separately. Simultaneously, ethylene glycol (EG) assisted BiOF was also synthesized by simple hydrolysis route (BiOF-C). The high reducing and stabilizing action of quercetin was demonstrated via spectroscopic and microscopic investigations, which revealed that the green BiOF-P and BiOF-Q samples followed almost similar morphology with much smaller size of the nanoplates and higher specific surface area than BiOF-C. Meanwhile, the leaf extract and quercetin covered an appreciable spectrum of solar radiation ranging from 600 to 700 nm, indicating the presence of coloring constituents i.e. chromophores in the structure. These chromophores imparted yellow color to the green samples leading to a narrow band gap, and boosted the optical window for high level of solar energy harvesting. Moreover, the electron accepting nature of the quercetin facilitated the charge injection to BiOF with subsequent regeneration process under visible light irradiation. The multiple synergistic effects resulted in significantly higher photo-degradation efficiency for benzotriazole (BT) and methyl orange (MO) by green BiOF-P and BiOF-Q samples than BiOF-C