Enhanced Visible Light Photocatalytic Performance of CeO2@Acidified g-C3N4 Nanoheterostructures for RhB Degradation

Photocatalysis with visible light is emerging as an effective solution for tackling environmental concerns, specifically focusing on the removal of dye pollution from wastewater. In this work, we have developed a scalable and efficient route for the synthesis of a (CeO₂@CN) nanocomposite by in situ co-pyrolysis of the cerium adipate complex and melamine, followed by acidification and exfoliation of the nanocomposite (CeO₂@A-gCN) for the degradation of rhodamine (RhB) dye in visible light. The synthesized photocatalysts were characterized by sophisticated techniques: X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, zeta potential, Brunauer–Emmett–Teller surface area measurements, and electrochemical impedance spectroscopy. The microstructure analysis confirmed the formation of an effective n–n type heterojunction with intimate close contact. The sample 3%CeO₂@A-gCN shows complete degradation compared to pristine CN (63%) and 3%CeO₂@CN (70%) with respective rate constant values of 0.011, 0.005, and 0.006 min^–1. The enhanced photocatalytic efficiency was due to synergistic interaction between the energy levels of CeO₂ and A-gCN, leading to highly improved photogenerated charge carrier separation, enhancement in specific surface area, reduced interfacial charge transfer resistance, and improved charge carrier transport. The charge separation and degradation mechanism was investigated in detail using photoluminescence spectroscopy, quenching and quantification experiments, and transient current response under light irradiation. 3%CeO₂@A-gCN demonstrated consistent stability, highlighting its suitability for practical wastewater treatment applications.