Scalable self-growth of magnetic Janus microparticles for microplastics degradation

Janus particles exhibiting different physical and chemical properties in a single particle have attracted tremendous attention for extensive applications, especially ones constructed from micro/nanoscale building blocks. However, a reliable and scalable fabrication of magnetic Janus particles with hierarchical structures and desired functions remains challenging. Herein, a self-growing strategy is proposed for magnetic Janus microparticles (MJMPs) composed of Fe 3 O 4 submicron spheres and photoactive BiOI nanosheets. The resultant MJMPs have a distinctive asymmetric three-dimensional hierarchical structure assembled from two-dimensional nanosheets and submicron particles. Such a structure not only achieves the enhancement of surface area, but also achieves good magnetic response for control and reuse as well as high photocatalytic ability for microplastics degradation. This work presents a facile and efficient approach for developing various Janus microparticles suitable for widespread practical applications.