Catalytic and Light-Driven ZnO/Pt Janus Nano/Micromotors:Switching of Motion Mechanism via Interface Roughness and Defect Tailoring at the Nanoscale

The first models of mesoporous ZnO/Pt Janus micromotors that show fuel‐free and light‐powered propulsion depending on the interface roughness are shown. Two models of ZnO semiconducting particles with distinct surface morphologies and pore structures are synthesized by self‐aggregation of primary nanoparticles and nanosheets into nanoscale rough and smooth microparticles, respectively. The self‐assembled nanosheet model (smooth) provides a large surface for the formation of a continuous Pt layer with strong adherence, whereas the discontinuous Pt species take place inside the inter‐nanoparticles pores in the self‐assembled nanoparticle model (rough). The effects of the interface, surface porosity, defect, and charge transfer on the light‐powered motion for both well‐designed mesoporous ZnO/Pt Janus micromotors are investigated and compared to find the underlying propulsion mechanisms. The degradation of two model pollutants is demonstrated as a proof‐of‐concept application of these carefully engineered Janus micromotors. In this work, it is shown that by discreet material fabrication together with semiconductor/metal interface charge transport interpretation, it would be possible to develop new light‐driven Janus micromotors based on other photocatalysts containing active surfaces such as TiO₂.