Biotemplated Shell Micromotors for Efficient Degradation of Antibiotics via Enhanced Peroxymonosulfate Activation

Self-propelled magnetic MnO 2 @pollen micromotors have been developed as active heterogeneous catalysts of peroxymonosulfate (PMS) activation for efficient degradation of antibiotics. The MnO 2 nanosheets (NSs) and Fe 3 O 4 nanoparticles (NPs) are constructed on hollow pollens with small openings, endowing the natural materials with multifunctional properties. MnO 2 NSs can decompose H 2 O 2 to provide propulsion for micromotor movement, and also cooperate with Fe 3 O 4 NPs to activate PMS to produce active free radicals SO 4 ·− . Together with the OH· generated by Fe 3 O 4 NPs and H 2 O 2 , the prepared micromotor catalyst can realize the degradation of tetracycline (TC) within several minutes. The self-propulsion and abundant bubble formation cause effective fluid mixing and intensification of mass transfer, making up the low diffusivity defect of traditional heterogeneous catalysts. Moreover, the magnetic properties lay a foundation for the long-range magnetic control and reutilization of heterogeneous catalysts, avoiding wastage and secondary contamination. The proposed self-propelled pollen micromotors provide a highly efficient, economic, and environmentally friendly platform for the degradation of antibiotics.