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

[Display omitted] •The decoration of conjugated polymer nanoparticles to TiO2 microsphere enables to obtain a self-propelled, Janus-type micromotor.•Facilitated transfer of the excited electrons from conjugated polymer to TiO2 enhances the propulsion and photocatalysis under visible light irradiation.•The movable micromotor shows successful uses in organic dye degradation under visible light. 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.