MXene-Derived g-C3N5/TiO2/Ti3C2 Nanoheterostructure Activated by Peroxymonosulfate for Photocatalytic Tetracycline Degradation under Visible Light

Graphical Under visible light, a Z-type heterojunction is formed between Ti 3 C 2 /TiO 2 and g-C 3 N 5 to enhance charge separation. Electrons and holes directly or indirectly react with PMS to generate free radicals such as · ,·OH, and 1 O 2 to degrade tetracycline. Photocatalysis-assisted peroxymonosulfate (PMS) activation is a promising technology for the degradation of antibiotics in water remediation. Herein, MXene-derived oxide (TiO 2 ) and g-C 3 N 5 Z-scheme ternary heterojunction photocatalytic composite materials are synthesized using an electrostatic self-assembly approach and characterized. The optimized g-C 3 N 5 /TiO 2 /Ti 3 C 2 (CNTT) heterostructure demonstrates exceptional photocatalytic activity for tetracycline (TC) removal, achieving 90% degradation within 60 min at an optimal g-C 3 N 5 :TiO 2 /Ti 3 C 2 mass ratio of 3:2. Remarkably, the system exhibits broad pH adaptability (80.8–96.3% TC removal across pH 2–12), overcoming the pH sensitivity limitations of traditional PMS-based processes. Mechanistic investigations reveal a synergistic photocatalysis-PMS activation pathway, with quenching experiments confirming , ·OH, · , and 1 O 2 , as dominant reactive species. The CNTT composite maintains 65.2% degradation efficiency after five cycles, demonstrating robust stability. Coexisting ions negatively influence TC removal in the order: H 2 PO 4 − > > Cl − > > . This work establishes the CNTT heterostructure as a promising, environmentally tolerant candidate for efficient pharmaceutical pollutant remediation in complex aqueous matrices.