Photocatalytic Microplastics “On-The-fly” Degradation via Motile Quantum Materials-Based Microrobots

Nano/micro-plastics pollution is an emerging global concern. A variety of biodegradable polymers have been synthesized to enhance the degradation of plastic materials and thereby avoid their accumulation in the environment. However, even biodegradable polymers can accumulate in environments under specific conditions and present a potential hazard. Here, antimony sulfide-based microrobots decorated with magnetite nanoparticles are designed for microplastics degradation. The propulsion of microrobots is enabled by two independent orthogonal physical modes via magnetic field and via light irradiation. Due to phoretic interactions, the microrobots exhibit affinity toward poly(3-hydroxybutyrate) (PHB) and poly(lactic acid) (PLA) microplastics, which enables subsequent transport of the microplastics in a transversal rotating magnetic field. The photocatalytic activity of Sb₂S₃ quantum material provides microrobots with the ability to degrade the microplastics under UV light irradiation in the “on-the-fly” regime without the need for any fuel. This proof-of-concept work shows efficient capture, transport, and photocatalytic degradation of microplastics and paves the way toward their elimination, especially in water environments.