Bipolar electrochemical mechanism for the propulsion of catalytic nanomotors in hydrogen peroxide solutions

Yang Wang, Rose M. Hernandez, David J. Bartlett, Julia M. Bingham, Timothy R. Kline, Ayusman Sen, Thomas E. Mallouk

Research output: Contribution to journalArticle

347 Scopus citations

Abstract

Bimetallic nanorods are propelled in aqueous solutions by the catalytic decomposition of hydrogen peroxide to oxygen and water. Several mechanisms (interfacial tension gradients, bubble recoil, viscous Brownian ratchet, self-electrophoresis) have been proposed for the transduction of chemical to mechanical energy in this system. From Tafel plots of anodic and cathodic hydrogen peroxide reactions at various metal (Au, Pt, Rh, Ni, Ru, and Pd) ultramicroelectrodes, we determine the potential at which the anodic and cathodic reaction rates are equal for each metal. These measurements allow one to predict the direction of motion of all possible bimetallic combinations according to the bipolar electrochemical (or self-electrophoretic) mechanism. These predictions are consistent with the observed direction of motion in all cases studied, providing strong support for the mechanism. We also find that segmented nanorods with one Au end and one poly(pyrrole) end containing catalase, an enzyme that decomposes hydrogen peroxide nonelectrochemically, perform the overall catalytic reaction at a rate similar to that of nanorods containing Au and Pt segments. However, in this case there is no observed axial movement, again supporting the bipolar electrochemical propulsion mechanism for bimetallic nanorods.

Original languageEnglish (US)
Pages (from-to)10451-10456
Number of pages6
JournalLangmuir
Volume22
Issue number25
DOIs
StatePublished - Dec 5 2006

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Fingerprint Dive into the research topics of 'Bipolar electrochemical mechanism for the propulsion of catalytic nanomotors in hydrogen peroxide solutions'. Together they form a unique fingerprint.

  • Cite this

    Wang, Y., Hernandez, R. M., Bartlett, D. J., Bingham, J. M., Kline, T. R., Sen, A., & Mallouk, T. E. (2006). Bipolar electrochemical mechanism for the propulsion of catalytic nanomotors in hydrogen peroxide solutions. Langmuir, 22(25), 10451-10456. https://doi.org/10.1021/la0615950