Photocatalytic degradation of sulfamethoxazole over S-scheme Fe₂O₃/g-C₃N₄ photocatalyst under visible light

The application of promising g-C₃N₄ has been limited by poor photogenerated electron-hole separation and limited absorption for visible light. Sulfamethoxazole (SMX) is a typical antibiotic drug that is used worldwide and hard to be disposed through conventional wastewater treatment methods. Herein, S-scheme Fe₂O₃/g-C₃N₄ heterojunction was successfully prepared via a facile one-step sintering method and applied to photodegrade SMX under visible light irradiation. The integration of Fe₂O₃ and g-C₃N₄ shows superior charge separation and light absorption ability. As a result, the removal efficiency of 11 wt% Fe₂O₃/g-C₃N₄ reaches to 99.2% within 30 min, which is visibly higher than 59.5% of pure g-C₃N₄. ·O₂⁻ and ·OH are demonstrated to be the predominant active species for SMX photodegradation, and the possible degradation pathway is also proposed based on electronic band structure of Fe₂O₃/g-C₃N₄ heterojunction. This study presents a facile construction of g-C₃N₄ based S-scheme photocatalyst and offers an environmentally friendly approach to effectively remove organic pollutants using renewable solar energy.