Exploiting electrolyte confinement effects for the electrosynthesis of two-engine micromachines

Abstract We exploit electrolyte confinement effects in porous membranes to electrosynthesize a two-engine micromachine from a single electrolyte solution. Taking advantage of the often undesired overplating observed in template-assisted deposition, we can produce micromachines consisting of hollow microstructures with a compositionally graded mushroom-like shape that consist of a manganese oxide-based stipe and an iron oxide-based cap. While the stipe acts as the catalytic motor of the machine, the cap serves as a magnetic steering wheel.