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

Abstract

Photocatalysis-assisted peroxymonosulfate (PMS) activation is a promising technology for the degradation of antibiotics in water remediation. Herein, MXene-derived oxide (TiO₂) and g-C₃N₅ Z-scheme ternary heterojunction photocatalytic composite materials are synthesized using an electrostatic self-assembly approach and characterized. The optimized g-C₃N₅/TiO₂/Ti₃C₂ (CNTT) heterostructure demonstrates exceptional photocatalytic activity for tetracycline (TC) removal, achieving 90% degradation within 60 min at an optimal g-C₃N₅:TiO₂/Ti₃C₂ 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 ¹O₂, 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: H₂PO₄⁻ > $$ > Cl⁻ > $$ > $$. This work establishes the CNTT heterostructure as a promising, environmentally tolerant candidate for efficient pharmaceutical pollutant remediation in complex aqueous matrices.