Fe and Cu co-doped graphitic carbon nitride as an eco-friendly photo-assisted catalyst for aniline degradation

A novel bimetallic coordinated g-C3N4 with Fe2O3 composite catalyst (FeCu-g-C3N4) was synthesized by simple calcination of Fe3+/Cu2+/melamine precursor. Its catalytic performance was analyzed via photodegrading aniline. The X-ray diffraction (XRD), field emission scanning electronic microscopy (FESEM), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) were employed to characterize the composition and structure of the catalysts. Results indicated that Fe mainly distributed in the Fe(III)-N coordination form and partly in Fe2O3 lattice, and Cu inserted at the interstitial positions of g-C3N4 in the Cu(I)-N form. The great optical property was also proved by ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), photoluminescence (PL) spectroscopy, and photocurrent responses. The heterogeneous photo-assisted catalyst exhibited excellent performance in activation of H2O2, resulting in 80% decomposition of aniline with low metal leaching in 6 h. The incorporation of Cu elevated the performance of degradation compared to that only iron doped. A synergistic catalytic effect between solid Cu(I) and Fe(III) accelerated the reduction of Fe(III). The ·OH and 1O2 were confirmed as major reactive oxygen species (ROS) identified by scavenging experiments and ESR, and e− was the most essential since it not only led to the generation of ROS but also participated in the circulation of Fe3+/Fe2+, Cu2+/Cu+, and Fe3+/Cu+. Furthermore, the possible catalytic mechanism was proposed based on the analysis.