Integrated treatment of tetracycline in complex environments with MIPs-based Fe3O4-Cu2O-Au nanocomposites: Selective SERS detection and targeted photocatalytic degradation

Tetracycline (TC) is widely distributed in environment and a significant environmental pollutant. It has been challenging to rapidly identify and effectively remove TC contaminants. This work produced a multifunctional Fe3O4-Cu2O-Au-MIPs nanocomposite (FCAu-MIPs NCs) based on molecular imprinting technology for selective SERS detection and photocatalytic degradation of TC. We synthesized FCAu NCs with various Au contents and analyzed the relationship between Au content and SERS performance using finite-difference time-domain (FDTD) technique. Exceptional SERS performance could be attributed to the dense distribution of multiple hotspots on the SERS substrate. The photocatalytic mechanism of FCAu-MIPs NCs towards TC was also discussed. The combination of the narrow-bandgap semiconductor Cu2O and noble metal Au with localized surface plasmon resonance (LSPR) effect facilitated efficient light absorption and enhanced charge carrier transfer efficiency. Both SERS detection limits as low as 10−9 M and selective photocatalytic degradation of TC in soil were achieved. Furthermore, FCAu-MIPs NCs were successfully recovered and reused with assistance of external magnetic field. After six cycles, outstanding SERS and photocatalytic capacities from FCAu-MIPs NCs could still be maintained. The FCAu-MIPs NCs with selective recognition ability to TC should thus hold tremendous applicative possibilities for highly sensitive detection and efficient degradation of TC.