Confined Tri‐Functional FeO<i><sub>x</sub></i>@MnO<sub>2</sub>@SiO<sub>2</sub> Flask Micromotors for Long‐Lasting Motion and Catalytic Reactions
Yangyang Yang, Lei Shi, Jingkai Lin, Panpan Zhang, Kunsheng Hu, Shuang Meng, Peng Zhou, Xiaoguang Duan, Hongqi Sun, Shaobin Wang
Abstract
Abstract H 2 O 2 ‐fueled micromotors are state‐of‐the‐art mobile microreactors in environmental remediation. In this work, a magnetic FeO x @MnO 2 @SiO 2 micromotor with multi‐functions is designed and demonstrated its catalytic performance in H 2 O 2 /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 x nanoellipsoids primarily trigger radical species ( • OH and O 2 •− ) to attack organics via Fenton‐like reactions. The coated MnO 2 layers on FeO x surface are responsible for decomposing H 2 O 2 into O 2 bubbles to provide a propelling torque in the solution and generating SO 4 •− and • OH for organic degradation. The outer SiO 2 microcapsules with a hollow head and tail result in an asymmetrical Janus structure for the motion, driven by O 2 bubbles ejecting from the inner cavity via the opening tail. Intriguingly, PMS adjusts the local environment to control over‐violent O 2 formation from H 2 O 2 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 x 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.