Confined Tri-Functional FeO @MnO @SiO Flask Micromotors for Long-Lasting Motion and Catalytic Reactions.

H O -fueled micromotors are state-of-the-art mobile microreactors in environmental remediation. In this work, a magnetic FeO @MnO @SiO micromotor with multi-functions is designed and demonstrated its catalytic performance in H O /peroxymonosulfate (PMS) activation for simultaneously sustained motion and organic degradation. Moreover, this work reveals the correlations between catalytic efficiency and motion behavior/mechanism. The inner magnetic FeO nanoellipsoids primarily trigger radical species ( OH and O ) to attack organics via Fenton-like reactions. The coated MnO layers on FeO surface are responsible for decomposing H O into O bubbles to provide a propelling torque in the solution and generating SO and OH for organic degradation. The outer SiO microcapsules with a hollow head and tail result in an asymmetrical Janus structure for the motion, driven by O bubbles ejecting from the inner cavity via the opening tail. Intriguingly, PMS adjusts the local environment to control over-violent O formation from H O decomposition by occupying the Mn sites via inter-sphere interactions and enhances organic removal due to the strengthened contacts and Fenton-like reactions between inner FeO and peroxides within the microreactor. The findings will advance the design of functional micromotors and the knowledge of micromotor-based remediation with controlled motion and high-efficiency oxidation using multiple peroxides.