Light-controlled bubble propulsion of amorphous TiO2/Au Janus micromotors

In this work, a bubble-propelled photoactivated amorphous TiO2/Au (Am-TiO2/Au) Janus micromotor has been demonstrated by utilizing the efficient photocatalytic H2O2 decomposition over the in situ H2O2 sensitized Am-TiO2 under UV irradiation. The power conversion of the micromotor experiences a process from UV light power, to chemical power and finally to mechanical power. The quantum efficiency of O-2 bubble evolution from photocatalytic decomposition of H2O2 reaches 28%, and the power conversion efficiency reaches 1.28 x 10(-9), which enables the micromotor to generate a strong bubble thrust propelling itself forward with a maximum speed of 135 mm s(-1). The motion state and speed of the Am-TiO2/Au micromotors can be reversibly, wirelessly and remotely controlled at will with an ultrafast response rate (less than 0.1 s) by regulating "on/off" switch and intensity of UV irradiation. Consequently, the as-developed Am-TiO2/Au micromotors may promise potential challenging applications in such as "on-the-fly" adsorption and decomposition of pollutants in water.