A Review on Photocatalytic degradation of Congo red Dye Using Graphene-BiFeO3 Nanocomposite

Abstract

The increasing discharge of synthetic dyes, particularly azo dyes such as Congo red, into water bodies has become a serious environmental concern due to their toxicity, stability, and resistance to biodegradation. In this study, graphene–BiFeO₃ nanocomposites were investigated as efficient visible-light-driven photocatalysts for the degradation of Congo red dye. Pure BiFeO₃ was synthesized using a chemical route followed by annealing, and the composite was prepared by ultrasonically dispersing BiFeO₃ with graphene in a suitable solvent medium.Structural analysis confirmed the formation of rhombohedral BiFeO₃ with minor impurity phases, while morphological studies revealed that BiFeO₃ nanoparticles were uniformly anchored on graphene sheets, providing a high surface area and improved interaction with dye molecules. Photocatalytic activity was evaluated under UV–visible light irradiation using a Congo red solution, and degradation was monitored through UV–Vis spectroscopy.The results demonstrated that the graphene–BiFeO₃ nanocomposite exhibited significantly enhanced photocatalytic performance compared to pure BiFeO₃. Approximately 75% degradation of Congo red dye was achieved within 120 minutes using the composite, whereas pure BiFeO₃ showed only about 40% degradation under similar conditions. This improvement is attributed to the synergistic effects of graphene, which enhances charge separation, reduces electron–hole recombination, and increases adsorption capacity.the study confirms that graphene–BiFeO₃ nanocomposites are promising, efficient, and sustainable photocatalysts for the treatment of dye-contaminated wastewater under visible light irradiation.