In-situ synthesized 2D MXene/TiO2/Fe hybrid with (001)–(101) surface heterojunction for degradation of tetracycline under visible light

Tetracycline (TC) as a common antibiotic has adverse effects on human healthy and biological survival. In this study, a novel MXene/TiO 2 /Fe hybrid was designed and successfully synthesized by combination method of calcination and hydrothermal reduction. The photocatalysts were characterized by PXRD , SEM , TEM , VSM and XPS, etc. It was found that MXene/TiO 2 /Fe exhibited 2D multilayer structure like MXene. The in-situ synthesized TiO 2 through calcinating MXene exhibited an octahedral biconical structure with exposed (001) and (101) facets. Surface heterojunction of (001) and (101) facets was formed within TiO 2 , which enhanced the separation of photogenerated electrons and holes. The residual MXene could play a role in co-catalyst to capture the photo-generated electrons from TiO 2 . Moreover, Fe nanoparticles not only optimize the band gap structure and increase the specific surface area, but also store the electrons as a good electrons acceptor, which further promote the separation of electrons and holes. The TC removal efficiency of optimal MXene/TiO 2 /Fe could reach 92% within 120 min. Moreover, the influence of external environment factors such as pH, catalyst dosages and common anions were investigated in detail. Mechanism analysis show that h + , •OH and •O 2 − are the main active substances. Finally, the degradation pathways were proposed according to LC-MS.