Synthesis of Snowman‐shaped Photocatalytic Microrotors and Mechanical Micropumps

Abstract We synthesize snowman‐shaped microrotors that are composed of TiO 2 and SiO 2 particles fused together and half‐coated with Au. The microrotors rotate in the presence of fuel and UV light and the rotation speed is readily modulated by the fuel concentration and the light intensity. Such a microrotor can be transformed into a mechanical micropump that hydrodynamically, rather than electrokinetically, pumps nearby fluids and particles, with a pump power that scales linearly with its rotation speed. This work thereby opens up a new way for the study of microrotors as micropumps.