Construction of a Fe₂O₃/Ti₃C₂Tx heterojunction photocatalyst with oxygen-rich vacancies and its photocatalytic properties

As a class of antibiotics, tetracycline (TC) poses a serious threat to aquatic environments, thereby necessitating new demands on their restoration. Herein, a Fe2O3/Ti3C2Tx heterojunction photocatalyst with abundant surface oxygen vacancies was prepared using a solvothermal method, which can promote the migration and separation of photogenerated electron-hole pairs and improve the catalytic degradation performance of the material. The experimental results revealed that the prepared Fe2O3/Ti3C2Tx heterojunction catalysts exhibited better TC degradation performance under simulated sunlight, corresponding to 2.5 times that of Fe2O3 and 5.1 times that of Ti3C2Tx. Fe2O3 and Ti3C2Tx formed a close contact interface, and the staggered energy-level structure achieved the rapid transfer of electrons, resulting in the formation of numerous oxygen vacancies during the conversion of Fe3+ to Fe2+; these oxygen vacancies not only changed the Fe2O3/Ti3C2Tx crystal structure but also provided additional active centers for the reaction. In addition, transient fluorescence spectroscopy and photocurrent experiments revealed that the method considerably improved the separation rate of photo-excited carriers and the corresponding optoelectronic capability. The possible degradation pathways were revealed by the determination of the TC post-degradation by-products. Moreover, toxicity modeling results revealed that most degradation intermediates were less toxic than TC. This study discusses the importance of heterojunctions with oxygen-rich vacancies for improving the performance of degraded TC and provides an effective strategy for constructing heterojunction photocatalysts, broadening the applications of Fe2O3 and Ti3C2Tx materials in environmental remediation.