Desenvolvimento de heterojunções de MOF/Nitreto de carbono grafítico (EuBDC/g-C3N4) para fotodegradação de corante

Abstract

The environmental impacts resulting from industrial growth and improper waste disposal have worsened over the years. The production of materials with catalytic activity emerges as a promising alternative to mitigate these issues. Although the development of pure catalysts is widely studied, the formation of heterojunctions has gained prominence, as it combines the individual properties of materials, enhancing their performance. In this context, this study describes the synthesis and characterization of heterojunctions

between the MOF Eu2(1,4-benzenedicarboxylate)3(H2O)4 and Graphitic Carbon Nitride (g- C3N4) in different mass compositions, aiming at their application in the photodegradation of

dyes. The samples were characterized using various analytical, structural, and morphological techniques, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TG), diffuse reflectance spectroscopy in the UV-Vis region, fluorescence spectroscopy, Zeta potential (Pcz), and scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS). The photocatalytic activities of the heterojunctions were evaluated using the rhodamine B dye, with the EuBDC/g-C3N4 (50/50) composition showing the best performance, achieving a photodegradation rate of 96.7% and a kinetic constant of k = 8,20 × 10−2 min−1. Tests with methylene blue suggested a photodegradation of 84% (k = 3.80 × 10−2 min−1), while for methyl orange, the results were 73% (k = 2.7 × 10−2 min−1) under simulated visible light irradiation with a power of 30 W. Additionally, tests with scavenger agents suggested that superoxide radicals (O2•−) play a central role in the degradation process. The photocatalytic stability of the material was assessed through reuse tests under optimized conditions, conducted over two consecutive cycles.