Photoactive brownmillerite Ba₂In₂O₅ for photocatalytic degradation of organic pollutants

In the present work, photoactivity of Ba₂In₂O₅ (BIO) is explored through degradation of aqueous persistent organic pollutants such as Norfloxacin (NF) in presence of natural solar irradiation, visible light as well as ultraviolet irradiation and in absence of a co-catalyst. To the best of our knowledge, this is the first report on degradation of persistent antibiotic NF by brownmillerite BIO. BIO is an inherent brownmillerite type oxide, synthesized through effective solution combustion method. The structural and morphological studies were performed using X-ray diffraction technique and scanning electron microscopy respectively. The effective optical bandgap (~2.5 eV) opens up the possibility of BIO being used as a photoactive material. The ability of BIO to generate charge carriers and produce photocurrent (~1.38 μA/cm²) was explored using photoelectrochemical measurements. About 58% degradation of NF was achieved in 75 min (with a rate constant ~ 0.012 min⁻¹) and appreciable recyclability. Besides NF, the sample was also utilized for photodegradation of common water pollutants from textile industries, such as methylene blue.