Extraction of Mechanical Work from Collective Motion of Pt Catalytic Particles Induced by Chemical Reactions

It has been previously reported that bacteria exhibiting a collective motion spin a gear-shaped particle that are much larger than themselves. Such a collective biological motion is expected to be useful for the development of novel energy conversion systems. In our laboratory, we observed that Pt catalytic particles, which have a simpler structure than living organisms, exhibit a unique collective motion (repeated cluster formation and collapse) in an aqueous ethanol solution. Herein, we demonstrate the extraction of mechanical work from this collective motion. We observed that the collective motion of the Pt particles causes translation for spherical particles and spinning motion for a gear-shaped particle. Furthermore, we estimated the energy conversion efficiency from chemical energy to mechanical work via collective motion of the Pt catalytic particles.