| Abstract
| - Active spatiotemporal control of electrochemical reactions through dynamic electrochemical potential gradientswas explored by investigating three different types of reactions on Au: alkanethiol SAM electrosorption, Cudeposition and stripping, and O2 evolution from H2O2 oxidation. Counterpropagating gradients composed oftwo different thiols differing either in terminal functionality or in chain length were prepared, and their kineticand environmental stability was inferred from spatially resolved contact angle measurements for samplesstored under varying environmental conditions for periods up to one month. Chain length was found to correlatestrongly with stabilitya requirement for stability being that at least one of the chains be at least C8 orlonger. Spatially directed Cu deposition on Au was demonstrated by forming Cu stripes on Au, establishingthat a sequence of different potential gradients could be used to define an area of deposition in the center ofa working electrode. Dynamic spatiotemporal control of Cu deposition on Au was achieved by translating apotential window, which encompassed the Cu redox waves, across the Au surface. The position of the Cu/Autransition was constant at a potential intermediate between the two waves, and the width of the transitionregion in the SPR images was narrower than either of the two electron transfer waves. Spatially directedoxidation of H2O2 was demonstrated by monitoring the formation of oxygen bubbles near the electrode.Consistent with predictions of the Butler−Volmer equation, the rate of bubble formation was found to dependon spatial position (overpotential) in these experiments.
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