Facile synthesis of bismuth-based photocatalysts using ionic liquids for enhanced photodegradation of organic dyes

In this study, BiOBr nanophotocatalysts were synthesized via a solution combustion method employing different fuel agents, 2-hydroxyethylammonium acetate (2-HEAA) and 2-hydroxyethylammonium formate (2-HEAF), to investigate the influence of fuel type on their structural and photocatalytic properties. Comprehensive characterization was conducted using various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and diffuse reflectance spectroscopy (DRS). Compared with conventional solution combustion synthesis (SCS) methods based on organic fuels, the ionic-liquid-assisted combustion process provides rapid energy release, resulting in enhanced crystallinity and improved visible-light absorption, particularly in the BiOBr(F) sample. Tauc plot analysis revealed a narrowed band gap (2.26 eV) for BiOBr(F), promoting more efficient charge-carrier generation. The photocatalytic activity of the prepared samples was evaluated under simulated solar irradiation through the degradation of methylene blue (MB) and Eosin Y dyes. The BiOBr nanophotocatalyst synthesized with 2-HEAF fuel achieved the highest photodegradation efficiencies, reaching 96.7% for MB and 87.6% for Eosin Y. Additionally, the effects of operational parameters, including initial dye concentration, pH of the solution, and photocatalyst dosage, were systematically examined. These findings underscore the critical role of fuel type in tuning the physicochemical properties of BiOBr nanostructures and optimizing their photocatalytic activity for potential wastewater treatment applications.