Solution‐Synthesized Multifunctional Janus Nanotree Microswimmer

Abstract Synthetic active matters are perfect model systems for non‐equilibrium thermodynamics and of great potential for novel biomedical and environmental applications. However, most applications are limited by the complicated and low‐yield preparation, while a scalable synthesis for highly functional microswimmers is highly desired. In this paper, an all‐solution synthesis method is developed where the gold‐loaded titania‐silica nanotree can be produced as a multi‐functional self‐propulsion microswimmer. By applying light, heat, and electric field, the Janus nanotree demonstrated multi‐mode self‐propulsion, including photochemical self‐electrophoresis by UV and visible light radiation, thermophoresis by near‐infrared light radiation, and induced‐charge electrophoresis under AC electric field. Due to the scalable synthesis, the Janus nanotree is further demonstrated as a high‐efficiency, low‐cost, active adsorbent for water decontamination, where the toxic mercury ions can be reclaimed with enhanced efficiency.