Moving photocatalyst of a titanium dioxide-based micromotor asymmetrically decorated with conjugated polymer dots

Abstract

A Janus-type TiO2-based micromotor was fabricated, in which visible-light-absorbing conjugated polymer dots (CPdots) were asymmetrically introduced to the TiO2 hemisphere. The wax-in-water Pickering emulsion method enabled obtaining Janus-type TiO2 microspheres decorated with CPdots, which were attached by electrostatic interaction. Electrons and holes were generated in the CPdots upon visible light absorption and the generated hole oxidized H2O2 used as a fuel. TiO2 suppressed the recombination of electrons and holes by accepting excited electrons from CPdots. The TiO2-based micromotor was moved by O2 produced under visible light. In addition, when H2O2 was decomposed, electrophoresis and diffusiophoresis occurred because of concentration gradient. A SiO2-based micromotor showed a much slower movement, indicating the necessity for TiO2. In addition, the moving TiO2 micromotor showed effectiveness in dye degradation via photocatalysis under visible light, irrespective of the lack of visible light absorbance by TiO2.

Keywords

• Visible-light driven micromotor
• TiO2
• Conjugated polymer dots
• Photocatalytic dye degradation