Sunlight-Driven Degradation of Persistent Antibiotic Oxytetracycline and Hydrogen Generation by a Nanostructured Brownmillerite Ba₂In₂O₅–TiO₂ Heterojunction

Present work reports the design and development of a nanostructured Ba₂In₂O₅–TiO₂ (BT)-heterostructured composite for photocatalytic hydrogen (H₂) generation and drug degradation. The composite revealed a shift toward the visible region in the absorption spectra, with the band-edge positions assisting in staggered type II heterojunction formation. A lower recombination rate of photogenerated electrons and holes could be observed for the BT composite from the photoluminescence spectra. Photoelectrochemical measurements on the composite reveal better photoconducting properties compared to parent materials. The composite could also generate H₂ at a rate of 1066 μmol/g/h (without an expensive cocatalyst), which fares better than many existing photocatalytic composites. The composite was also found to be useful for enhanced degradation of the antibiotic drug oxytetracycline by up to 95% with a rate constant of 0.02 min^–1. Recyclability experiments and various studies on the sample pre- and postdegradation studies support its chemical stability. This work reveals the multifunctional nature of the composite for energy as well as environmental remediation.