Highly active BiFeO3–g-C3N4 S-scheme heterojunction with improved antibiotic degradation under visible-light: revealing mechanism

Abstract

The photocatalyst S-scheme BiFeO₃–g-C₃N₄ had been prepared by combining calcination and hydrothermal reaction. 10% BiFeO₃–g-C₃N₄ composite showed the greatest photocatalytic effect during tetracycline hydrochloride degradation (TC-HCl, 99.7% removal) within 100 min. Meantime, the photocatalytic efficacy was further confirmed by the removal efficiency of ciprofloxacin(CIP, 98.2% removal). The formation of S-scheme heterostructure and matching valence band and conduction band may be responsible for the improved photocatalytic efficiency of BiFeO₃–g-C₃N₄. This leads to the rapid separation of photo-induced carriers, increased electronic transport capacity, and extended carrier lifetime. A study was done on the potential mechanism by employing chemical scavenger experiment revealing the paramount role of O₂⁻. The composite could maintain photocatalytically stable even after five consecutive reaction cycles. The recovery efficiency of 10% BiFeO₃–g-C₃N₄ was high because of the magnetic property of BiFeO₃, which was convenient for the recycling process. The produced photocatalyst has potential use in the field of photocatalysis, and this work provides a novel thought to raise the photocatalysts recovery efficiency during recycling.