Integration of BiOI nanosheets into bubble-propelled micromotors for efficient water purification

Integration of 2D layered materials into micromotors is of great interest for scientists since 2D materials can endow micromotors with new characteristics or enhance their intrinsic properties. In this work, we develop the BiOI-based self-propelled micromotors (i.e., rGO/ZnO/BiOI/Co-Pi/Pt micromotors) with tubular and arc geometric shapes via template-assisted electrochemical deposition method. BiOI, constructed by nanosheets, is a visible-light-excited photocatalyst. The elaborately designed heterostructure is able to promote the charge separation and transport capacity of BiOI. Each micromotor can not only exhibit vigorous stirring-like movement for self-propulsion but also lead to enhanced photocatalytic dynamics for dye degradation. Using Rhodamine 6G as the dye pollutant model, BiOI-based micromotors can degrade 94% of dye molecules within 30 min under visible light illumination while their degradation efficiency is only 5.2% when in dark. The dye degradation mechanism is mainly based on the generation of reactive oxygen species during the photocatalysis process. The synergistic effect among i) “on-the-fly” chemistry, ii) the collective behavior of micromotors and iii) the visible-light-excited BiOI photocatalyst with synthetic nanoflake morphology and well-designed heterojunction make an efficient and active photocatalytic platform for water purification.