Semiconductor-Based Microswimmers: Attention to Detail Matters

Colloidal active matter is known for its sensitivity to external conditions; for example, the swimming speeds depend strongly on substrates, fuel concentration, and in the case of light-driven colloids, the illumination. While these points are regularly considered, the nanoscopic material properties of the motor bodies are often barely mentioned, but they are highly influential in the case of photocatalysts. In order to demonstrate the influence of subtle differences in chemical composition and interfacing between the different material compounds, we designed a system based on colloidal titania spheres asymmetrized by different nanoscale cobalt oxide species. We examine how the material properties and combinations lead to highly specific catalytic activity and cross-relate the subtle differences to the typical active behaviors of these complex materials.