Efficient tetracycline degradation using carbon quantum dot modified TiO₂@LaFeO₃ hollow core shell photocatalysts

Efficient harnessing of solar energy presents a significant challenge in environmental cleanup efforts. This study develops a highly effective carbon quantum dots-modified hollow core-shell TiO₂-LaFeO₃ heterojunction photocatalyst (CDs-TLFO). Structural analysis confirmed that nanosheets are loaded with CQDs, forming a hollow core-shell structure with intimate interconnection. Photocatalytic experiments reveal that CDs-TLFO degrads tetracycline hydrochloride (TC) 2.02 times faster than TLFO alone, and significantly outperformes h-TiO₂ and LaFeO₃ (11.28 and 2.78 times, respectively). This enhancement is attributed to CQDs acting as electron acceptors with upconversion properties, enhancing the separation of e^--h⁺ pairs and boosting visible light absorption. Integration of CQDs onto the TLFO surface creates numerous active sites and enhances visible light absorption. SEM and TEM tests confirm that the catalyst has a hollow core-shell structure. ESR tests and radical trapping experiments indicate that the high degradation efficiency of the catalyst mainly owns to the synergistic effect of hydroxyl radicals (·OH) and superoxide radicals (·O₂^-). The reusability and stability of the catalysts are investigated, potential TC degradation pathways are proposed as well as the photocatalytic reaction mechanism is revealed. This research introduces promising avenues for environmental cleanup and offers a straightforward, energy-efficient, and environmentally friendly method for producing CDs-TLFO heterojunction materials with superior photocatalytic capabilities.