Facile Fabrication of Bubble-Propelled Micromotors Carrying Nanocatalysts for Water Remediation

Abstract

A facile and flexible approach is developed to fabricate bubble-propelled mesoporous micromotors carrying nanocatalysts for efficient water remediation. The micromotors are prepared by simply coating the hemispherical surface of Fe3O4-nanoparticle-containing mesoporous SiO2 microparticles with a polydopamine layer for decorating Ag nanoparticles, based on the versatile adhesion and reduction properties of polydopamine. The Fe3O4 nanoparticles can produce OH radicals from H2O2 for pollutant degradation via Fenton reaction, whereas the mesoporous SiO2 matrix provides large surface area with anchored Fe3O4 nanoparticles for improved degradation performance. Moreover, the Ag nanoparticles can decompose H2O2 into oxygen bubbles for powering the movement of micromotors to further enhance the pollutant degradation. The micromotors that synergistically integrate these functions enable efficient degradation of pollutants, such as methylene blue demonstrated in this work, for water remediation. This approach offers a simple and versatile strategy for creating micromotors with flexible compositions and structures for applications in water remediation, drug delivery, and cargo transport.

From Passive Inorganic Oxides to Active Matters of Micro/Nanomotors

“…Furthermore, the micromotors are collected and reused after the oil removal in the presence of magnetic Fe 3 O 4 . Similarly, the walnut‐like SiO 2 ‐based micromotors [ 85b ] loaded Fe 3 O 4 could be separated by a magnetic field after the motor collected the oil droplets. In addition, one fully inorganic oxide complex microjet of FeSiMnO x (Fe 2 O 3 /SiO 2 ‐MnO 2 ) is synthesized and could remove contaminants under the combined action of photocatalysis and Fenton reaction.…”

“…Moreover, combination of iron oxide (Fe 2 O 3 or Fe 3 O 4 ) NPs within the SiO 2 ‐ or MnO 2 ‐based micromotors allows the magnetic recycling and enhances the catalytic capability. [ 45b,83c,84b,85 ] Iron oxide NPs are magnetically available and can generate OH radicals from H 2 O 2 for pollutant degradation by Fenton reaction. Generally, Fe 3 O 4 NPs are loaded on matrix of mSiO 2 or polymer, providing photocatalytic functions, along with magnetic guidance and feasible removal.…”

Symmetric Catalytic Pt-MnO2@Carbon Microspheres as Micromotors for Dynamic Pollutant Remediation

“…The rapid development of nanotechnology has resulted in diverse strategies and techniques for the fabrication of such micro/nanomotors, and bimetallic catalytic nanowires, microtubular microrockets, Janus microspheres and supermolecule-based nanomotors have all been proposed. [27][28][29] Tubular micro/nanomotors are typically fabricated via a rolling-up process, template-assisted electrodeposition or template-assisted layer-by-layer assembly. 27,28 In contrast, the techniques developed for the fabrication of Janus micromotors include physical vapor deposition, asymmetric bipolar electrodeposition, assembly and trapping of micro/ nanoparticles and the assembly and incorporation of synthetic molecules.…”

“…[27][28][29] Tubular micro/nanomotors are typically fabricated via a rolling-up process, template-assisted electrodeposition or template-assisted layer-by-layer assembly. 27,28 In contrast, the techniques developed for the fabrication of Janus micromotors include physical vapor deposition, asymmetric bipolar electrodeposition, assembly and trapping of micro/ nanoparticles and the assembly and incorporation of synthetic molecules. 27,28 However, the existing methods tend to comprise troublesome multistep processes and sometimes require the utilization of expensive equipment to asymmetrically engineer various products, which greatly hinders the further development of micromotors for practical applications.…”

“…27,28 In contrast, the techniques developed for the fabrication of Janus micromotors include physical vapor deposition, asymmetric bipolar electrodeposition, assembly and trapping of micro/ nanoparticles and the assembly and incorporation of synthetic molecules. 27,28 However, the existing methods tend to comprise troublesome multistep processes and sometimes require the utilization of expensive equipment to asymmetrically engineer various products, which greatly hinders the further development of micromotors for practical applications. Therefore, the development of a facile, e±cient strategy for the continuous fabrication of bubble-propelled micromotors is still a requirement.…”