Reversible Adsorption of Outer-Sphere Redox Molecules at Pt Electrodes.
Adsorption often dominates the response of nanofluidic systems due to their high surface-to-volume ratios. Here we harness this sensitivity to investigate the reversible adsorption of outer-sphere redox species at electrodes, a phenomenon that is easily overlooked in bulk measurements. We find that even though adsorption does not necessarily play a role in the electron-transfer process, such adsorption is nevertheless ubiquitous for the widely used outer-sphere species. We investigate the physical factors driving adsorption and find that this counterintuitive behavior is mediated by the anionic species in the supporting electrolyte, closely following the well-known Hofmeister series. Our results provide foundations both for theoretical studies of the underlying mechanisms and for contriving strategies to control adsorption in micro/nanoscale electrochemical transducers where surface effects are dominant.
MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands.
Dileep
D
Mampallil
MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands.
Klaus
K
Mathwig
MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands.
Shuo
S
Kang
MESA+ Institute for Nanotechnology, University of Twente, Carre 4409, Achterhorst, 7500AE Enschede, The Netherlands.
Serge G
SG
Lemay
Hofmeister series; adsorption; nanofluidics; outer-sphere species; redox cycling