Wastewater Mediated Activation of Micromotors for Efficient Water Cleaning

We present wastewater-mediated activation of catalytic micromotors for the degradation of nitroaromatic pollutants in water. These next-generation hybrid micromotors are fabricated by growing catalytically active Pd particles over thin-metal films (Ti/Fe/Cr), which are then rolled-up into self-propelled tubular microjets. Coupling of catalytically active Pd particles inside the micromotor surface in the presence of a 4-nitrophenol pollutant (with NaBH4 as reductant) results in autonomous motion via the bubble recoil propulsion mechanism such that the target pollutant mixture (wastewater) is consumed as a fuel, thereby generating nontoxic byproducts. This study also offers several distinct advantages over its predecessors including no pH/temperature manipulation, limited stringent process control and complete destruction of the target pollutant mixture. The improved intermixing ability of the micromotors caused faster degradation ca. 10 times higher as compared to its nonmotile counterpart. The high catalytic efficiency obtained via a wet-lab approach has promising potential in creating hybrid micromotors comprising of multicatalytic systems assembled into one entity for sustainable environmental remediation and theranostics.