Light-Triggered Catalytic Performance Enhancement Using Magnetic Nanomotor Ensembles.

Fengtong Ji,Ben Wang,Li Zhang

doi:10.34133/2020/6380794

Abstract

Micro/nanomachines have attracted extensive attention in the biomedical and environmental fields for realizing functionalities at small scales. However, they have been rarely investigated as active nanocatalysts. Heterogeneous nanocatalysts have exceptional reusability and recyclability, and integration with magnetic materials enables their recovery with minimum loss. Herein, we propose a model active nanocatalyst using magnetic nanomotor ensembles (MNEs) that can degrade contaminants in an aqueous solution with high catalytic performance. MNEs composed of a magnetite core coated with gold nanoparticles as the nanocatalyst can rotate under the action of a programmable external field and carry out rapid reduction of 4-nitrophenol (4-NP). The hydrogen bubbles generated in the catalytic reaction provide random perturbations for the MNEs to travel in the reaction solution, resulting in uniform processing. The reduction can be further boosted by irradiation with near-infrared (NIR) light. Magnetic field induces the rotation of the MNEs and provides microstirring in the catalysis. Light enhances the catalytic activity via the photothermal effect. These MNEs are also capable of moving to the targeted region through the application of a programmable magnetic field and then process the contaminant in the targeted region. We expect that such magnetic MNEs may help better in applying active heterogeneous nanocatalysts with magnetic field and light-enhanced performance in industrial applications due to their advantages of low material cost and short reaction time.

Highlights

Micro/nanomotors have aroused considerable interest in the past decade due to their potential applications in biomedical engineering [1] and environmental remediation [2]
Substantial progress has been achieved for improved self-propulsion of micro/nanomotors driven by various chemical reactions, further development of micro/nanomotors is still required to enable their industrial applications
Transmission electron microscopy (TEM) images presented in Figures 2(a) and 2(b) show the overall view and an enlarged view of the Fe3O4 NPs with excellent crystallinity, obtained by the hydrothermal treatment of the Fe3O4 NPs synthesized by coprecipitation

Summary

Introduction

Micro/nanomotors have aroused considerable interest in the past decade due to their potential applications in biomedical engineering [1] and environmental remediation [2]. The real time control via magnetic actuation is capable of making nanomotors perform collectively [28] Such possibilities may promote nanomotors to be active during the whole sequence of contaminants processing, i.e., catalysis, targeted migration, and removal. We propose a model of an active nanocatalyst using magnetic nanomotor ensembles (MNEs) to improve the catalytic performance from the combined effects of the magnetic field and irradiation from an NIR laser (Figure 1(a)). MNEs reach a high catalytic activity under the hybrid stimuli of magnetic field and light, demonstrating their potential industrial impact with regard to the improved catalytic efficiency, shortened catalytic cycle, and cost savings from the reduced noble metal usage

Results and Discussion

Conclusion

Materials and Methods

Conflicts of Interest