Catalytic gold nanoparticle driven pH specific chemical locomotion

Abstract

Gold nanoparticle (Au NP) catalyzed decomposition of alkaline hydrogen peroxide has been utilized in driving chemical locomotives in a liquid. Au NPs deposited on spherical micron sized polymer resin beads catalyzed the decomposition of H₂O₂ in the pH range 9.1–10.8. The O₂ gas bubbles produced in the decomposition moved the beads upward with average velocities that depended on the pH of the solution. The measured average velocity of the bead increased with the increase in pH in the range 9.1–10.8. Above this pH, the self-decomposition of H₂O₂ produced sufficient bubbles in the medium that made the motion haphazard and thus prevented a clear measurement of the velocity. The observed accelerated motion of the locomotive has been explained by considering the time-dependent growth of O₂ gas bubbles on the polymer, while taking into consideration desorption and other factors.