Synthesis of carbon dot LDHs@MnO₂ tubular magnetic micromotors for detection and degradation of oxytetracycline

Antibiotic residues in water are closely related to human health and environment. Therefore, it is of great significance to detect and remove antibiotics in water. Here, by integrating nanozyme activity and self-propelled movement that can promote the mass transfer and diffusion in solution, a novel dual-functional CDsLDHs@MnO2/Fe3O4 magnetic micromotor with high exposed active sites for the detection and removal of oxytetracycline (OTC) was prepared by a biotemplate method. The micromotor could move autonomously in aqueous solution containing H2O2, reaching a mean speed of 158.35 +/- 11.64 mu m/s in 5 wt% H2O2. Due to the synergy of motion and the CDs-enhanced peroxidase-like activity, the micromotor could easily detect OTC in aqueous solution with a low detection limit (0.291 mu M), wide detection range (0-100 mu M), high selectivity, and a high magnetic recovery rate (near 85 %). More importantly, these micromotors also enabled rapid degradation of OTC through Fenton and Fenton-like reactions, reaching 87.93 % in the presence of 5 wt% H2O2. This work could provide a new idea for detecting and removing antibiotics from water.