heavy 
 metal contamination in water is a serious risk to the public 
 health and other life forms on earth . 
 current research in nanotechnology 
 is developing new nanosystems and nanomaterials for the fast and efficient 
 removal of pollutants and heavy metals from water . here , we report 
 graphene oxide - based microbots ( gox - microbots ) as active self - propelled 
 systems for the capture , transfer , and removal of a heavy metal ( i.e. , 
 lead ) and its subsequent recovery for recycling purposes . 
 microbots 
 structure consists of nanosized multilayers of graphene oxide , nickel , 
 and platinum , providing different functionalities . 
 the outer layer 
 of graphene oxide captures lead on the surface , and the inner layer 
 of platinum functions as the engine decomposing hydrogen peroxide 
 fuel for self - propulsion , while the middle layer of nickel enables 
 external magnetic control of the microbots . 
 mobile gox - microbots remove 
 lead 10 times more efficiently than nonmotile gox - microbots , cleaning 
 water from 1000 ppb down to below 50 ppb in 60 min . 
 furthermore , after 
 chemical detachment of lead from the surface of gox - microbots , the 
 microbots can be reused . 
 finally , we demonstrate the magnetic control 
 of the gox - microbots inside a microfluidic system as a proof - of - concept 
 for automatic microbots - based system to remove and recover heavy metals .