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Engineering the shape of nanoparticles has emerged as an effective approach for optimizing their physical/chemical properties. In particular, two-dimensional (2D) nanostructures with their high surface area/volume ratio have opened up exciting opportunities for developing advanced anisotropic materials and facilitating chemical processes that demand high levels of surface interactions. Although the great potential of low-dimensional 2D nanoswimmers has been suggested by theoretical works, very little experimental study has been undertaken thus far. Here we fabricated a low-dimensional magnetic nanomotor based on discotic barium ferrite nanoplates. We demonstrated that the “fuel-to-motion” behavior and the enhanced diffusion of nanoswimmers are not limited to just 0D nanospheres or 1D nanorods but are also applicable to 2D nanoplates. In addition, the 2D nanoswimmers showed excellent catalytic performance in removing molecular and particle stains on cloth likely due to their catalytic activity as well as active locomotion that enhanced microconvection of solution. This study validated a new self-powered nanomachine for cleaning application without any requirement of surfactants or external mechanical energy.

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Janus colloidal surfactants with opposing wettabilities are receiving attention for their practical application in industry. Combining the advantages of molecular surfactants and particle-stabilized Pickering emulsions, Janus colloidal surfactants generate remarkably stable emulsions. Here we report a straightforward and cost-efficient strategy to develop Janus nanoplate surfactants (JNPS) from an aluminosilicate nanoclay, halloysite, by stepwise surface modification, including an innovative selective surface modification step. Such colloidal surfactants are found to be able to stabilize Pickering emulsions of different oil/water systems. The microstructural characterization of solidified polystyrene emulsions indicates that the emulsion interface is evenly covered by JNPS. The phase behaviors of water/oil emulsion generated by these novel platelet surfactants were also investigated. Furthermore, we demonstrate the application of JNPS for enhanced oil recovery with a microfluidic flooding test, showing a dramatic increase of oil recovery ratio. This research provides important insights for the design and synthesis of two-dimensional Janus colloidal surfactants, which could be utilized in biomedical, food and mining industries, especially for circumstances where high salinity and high temperature are involved.