TMD-Material-Integrated Micromachines: Synthesis, Propulsion, and Application

The pursuit of artificial micro/nanoscale intelligent machines that can carry out multi-tasks demands the fabrication and integration of innovative functional materials. In the past decades, transition metal dichalcogenide (TMD) materials, such as molybdenum disulfide (MoS₂), have received immense attention owing to their unique electrical, catalytic, biological, and mechanical properties for myriad applications. Nevertheless, TMD materials have been rarely explored in the research of micro/nanomachines, the success of which could bring unparallel opportunities to basic research and applications in micro/nanorobotics. Herein, we report the design, fabrication, and performance of an original one-side-open MoS₂/TiO₂ hollow Janus micromotor (OHJM) that autonomously propels in an aqueous solution with light simulation. Owing to the unique type-II bandgap alignment of the MoS₂/TiO₂ heterojunction, the OHJMs exhibit enhanced propulsion due to an extended light absorption to the visible region. They also demonstrate anomalous speed acceleration in response to an ionic environment, observed for the first time among various chemical-driven micromotors. Finally, the MoS₂/TiO₂ micromotors are applied for water treatment and disinfect 99.999% of E. coli in one hour. This research highlights the potentials of TMD materials for both the fundamental investigation and applications of micro/nanomachines.