Sol-gel auto combustion synthesis of Cu-doped NiFe2O4/GCN/RGO photocatalyst: characterization and mechanistic insights for environmental remediation
摘要
The rapid pace of industrialization has intensified environmental contamination, necessitating the development of highly efficient and sustainable photocatalytic material for wastewater remediation. In this work, a novel Cu-doped NiFe2O4/GCN/RGO S-scheme photocatalyst was successfully synthesized via a facile sol-gel auto-combustion approach. Unlike conventional ferrite/GCN photocatalysts, the present system integrates Cu substitution into the NiFe2O4 lattice with reduced graphene oxide as an electron mediator, thereby promoting efficient interfacial charge transfer, enhanced visible-light utilization, and suppressed e−/h+ pair recombination through a robust S-scheme charge transfer pathway. Ciprofloxacin was selected as a representative emerging pharmaceutical contaminant to evaluate the photocatalytic performance. The synthesized nanocomposite was comprehensively characterized using advanced analytical techniques to investigate its crystal structure, chemical bonding, morphology, elemental composition, microstructure, surface chemical states, optical properties, and stability. Owing to the synergistic effects of Cu doping, S-scheme heterojunction formation, and the conductive RGO network, the optimized Cu-doped NiFe2O4/GCN/RGO photocatalyst exhibited a degradation efficiency of 95.08% with an apparent kinetic rate constant of 0.0201 min− 1, approximately 5.03 times higher than that of pristine GCN under visible-light irradiation within 130 min. The outstanding photocatalytic performance demonstrates that the rational integration of Cu-doped NiFe2O4, GCN, and RGO offers a promising strategy for developing high-performance ferrite-based S-scheme photocatalysts for the efficient removal of pharmaceutical pollutants from wastewater, providing a practical and sustainable solution for environmental remediation.