Highly efficient MOF-based self-propelled micromotors for water purification

Abstract

Self-propelled metal–organic framework (MOF)-based Janus micromotors that propel autonomously in hydrogen peroxide and display effective remediation of contaminated water is presented in this work. The novel Janus micromotors rely on the asymmetric deposition of a catalytically active Ag patch on the surface of MOF composite microspheres. The active Ag sites are used for the splitting of H₂O₂ to form oxygen bubbles. As a result, these Janus micromotors can reach a high speed of over 310 μm s⁻¹ due to effective bubble propulsion, which is comparable to common Pt-based micromotors. By coupling the high catalytic capacity of MOFs with their autonomous propulsion, the MOF-based micromotors are shown to play a dominant role in the effective removal of organic pollutants. In addition, scanning electronic microscopy, Fourier-transform infrared spectroscopy and energy dispersive X-ray spectroscopy are performed to verify their morphology and composition. Based on the obtained results, a potential mechanism of the motion and the high catalytic activity is also proposed. It is expected that these energy saving micromotors with catalytic activity should be unprecedentedly spread in real applications.