One body, two hands: photocatalytic function- and Fenton effect-integrated light-driven micromotors for pollutant degradation.

The threat of water pollution represents a serious global concern and requires rapid and efficient neutralization methods. Herein, we report novel two-in-one light-driven micromotors, i.e., light-driven TiO2-Fe Janus micromotors with both photocatalysis and photo-Fenton processes, for efficiently degrading organic pollutants in contaminated water. The TiO2-Fe micromotors moved rapidly by utilizing the photocatalytic H2O2 decomposition over TiO2 under UV irradiation, as well as generating highly reactive oxygen species responsible for the in situ degradation of the organic pollutants into non-harmful products. Notably, such coupling of photocatalysis generated on the TiO2 sides and the photo-Fenton process generated on the Fe sides, along with the rapid movement of these catalytic Janus micromotors, results in a synergetic effect that can greatly enhance the degradation of organic pollutants. The degradation efficiency of the TiO2-Fe micromotors is 52-fold that of only Fenton effects, and it is further improved by 40% compared to photocatalytic degradation alone. Considering the excellent advantages of the high efficiency, simple structure, reusability and the bubble-driven property, the new "on-the-fly" TiO2-Fe micromotor-based method has a promising potential for future water cleaning and waste-water treatments.