Novel metal-free intercalation of g-C3N4 using hyperbranched copolymer for efficient photocatalytic degradation of tetracycline

Abstract

Herein, graphitic carbon nitride (g-C3N4) structure was successfully intercalated with a hyperbranched copolymer (poly(DEAEMA-co-MMA)) to utilize a novel and applicable photocatalyst (PCN) for antibiotic degradation under visible light illumination. The as-synthesized catalysts were systematically characterized by XPS, FTIR, TEM, XRD, BET, DRS, PL and EIS methods. The intercalation of g-C3N4 with copolymer increased the specific surface area from 46.8 to 210.2 m2/g, leading to increased active sites on the catalyst surface. DRS, PL, EIS techniques and the transient photocurrent responses demonstrated enhanced visible-light absorption and separation efficiency of photo-generated electron-holes for PCN catalyst. XPS analysis revealed the formation of new delocalization π bonds which improves the electronic conductivity. The photocatalytic performance on tetracycline (TC) degradation on PCN catalyst was investigated under visible light irradiation. The intercalated g-C3N4 exhibited much higher photoactivity toward TC degradation (90 %) comparing with bare g-C3N4 (65 %). The enhanced photocatalytic performance of PCN catalyst was mainly assigned to the increased surface area and low recombination rate of the photogenerated charge carriers. Furthermore, the degradation was greatly influenced in the presence of scavengers, suggesting the crucial role of O2− radicals on the performance. The photoactivity was strongly affected by water matrix, which the degradation efficiency altered with high concentrations of anions. In addition, reusability tests revealed that the catalyst was stable until fifth cycle. This work provides a new insight for intercalation of the photocatalyst using a hyperbranched copolymer for water treatment applications.