Hematite Fe₂O₃@nitrogen-doped graphene core-shell photocatalyst for efficient cephalexin degradation under visible light irradiation

Recently, photocatalysis has been a promising technology for removing pharmaceutical antibiotics due to low energy utilization and cost-effectiveness. In this study, hematite Fe₂O₃ was encapsulated with nitrogen-doped graphene to produce an active and stable Fe₂O₃@NGr core-shell flatform for photocatalytic degradation of cephalexin. Fe₂O₃@NGr under visible light irradiation delivered an impressive cephalexin degradation efficiency of 90% within 60 min, superior to free-standing Fe₂O₃ (40%) and NGr (15%) species, respectively. Also, it could bring a lasting catalyst for light-driven cephalexin removal. The improvements were synergistically attributed to two following effects. First, the facile generation and transfer of electron-hole pairs in the Fe₂O₃@NGr core-shell design were achieved under visible light. Second, the active surface of NGr shell weakly bound to the CO gas as a central intermediate species in the decomposition by-products, speeding up the cephalexin removal. Thus, these two basic factors provided mechanistic insights into the working of Fe₂O₃@NGr core-shell system in terms of cephalexin degradation under visible light.