Autonomous propulsion of platinum-based catalytic micro/nanomotors

Abstract

This work focuses on the investigation of platinum-based catalytic micro/nanomotors, including working mechanism, design, fabrication and related characterization. Three different categorized micro/nanomotors have been investigated, and key observations can be summarized as follows: i.A novel disk-like gold-nickel-platinum nanomotor is proposed. A bubble propulsion mechanism is employed to characterize the locomotion of the proposed nanomotor. The propulsion activities of the nanomotor are investigated at different hydrogen peroxide concentrations and different temperatures. Moreover, the magnetic effect on the propulsion of the nanomotor is also characterized. In addition, for the first time the three-dimensional propulsion of the nanomotor is characterized by using digital holographic microscope. ii. Two different types of gold-nickel-platinum nanojets are designed. One is with singular off-center nanoengine, the other one is with dual off-center nanoengines. The self-steerable propulsion activities of these two different nanojets are characterized at different hydrogen peroxide concentrations. The results show that the nanojet with singular off-center nanoengine is able to propel forward circularly; while the nanojet with dual off-center nanoengines can move forward linearly. iii.Another novel micro/nanomotor (platinum-nickel-SU-8 microrocket) is proposed. The microrocket has an eccentric nanoengine. A circularly self-steerable propulsion mechanism is proposed for characterizing the autonomous locomotion of the microrocket. The circularly steerable propulsion of the microrocket is characterized at different hydrogen peroxide concentrations. The results reveal that the speed of the microrocket increases with the increment of hydrogen peroxide concentrations. These observations prove the fabrication feasibility of newly designed micro/nanomotors. The wide applications of these micro/nanomotors can be expected.