Self-Propelled Micro-/Nanomotors of ZnO Nanoshuttles Induced by Surface Defects

To accomplish various complex tasksin the microworld,micro-/nanomotors(MNMs) with diverse swimming characteristics have attracted more andmore attention. In this work, ZnO nanoshuttles were synthesized bya simple hydrothermal method. In addition, MNMs based on ZnO nanoshuttleshave been designed, exhibiting self-propelled swimming characteristicswith three motion modes of shake, rotation, and translation in water.It is revealed that the asymmetrically distributed defects on thesurface of ZnO nanoshuttles are responsible for the swimming modes.The unique shuttle-like structure helps to reduce the drag in a lowReynolds number environment and endows the self-propelled ZnO nanoshuttlemotor with a relatively high swimming velocity (5.16 mu m/s).In addition, to demonstrate the versatility and openness of ZnO nanoshuttleMNMs, ZnO/Co magnetic MNMs and ZnO/TiO2 Janus MNMs wereprepared by simple Co doping and TiO2 coating, respectively.This study reveals the possible role of surface defects in regulatingthe motion behavior of ZnO-based MNMs and also provides a feasiblelow-cost method for the large-scale fabrication of self-asymmetricfuel-free micro-/nanomotors.