Nanoelectrode ensembles (NEEs) are popular platforms for sensor design and electroanalysis largely due to ease of fabrication, and operational advantages including rapid response time, increased sensitivity, small iR drop, and high mass-transport rates compared to a single macroelectrode, and enhanced faradaic currents compared to a single nanoelectrode (NE). The majority of experimental and theoretical studies for NEEs have involved macro-supports of large geometric area that operate primarily under transient conditions. In contrast, we have been working with NEEs having an overall geometric area of ultramicro-dimensions (i.e., 10 micrometer diameter) that operate under simpler steady-state conditions due to their higher mass-transport rates. We recently reported the development of arrays of these so-called micro-NEEs.1,2 We will discuss the fabrication of micro-NEEs, their theory, their characterization using steady-state voltammetry (SSV) and scanning electrochemical microscopy (SECM), and their unique advantages in electrocatalysis applications. Specifically, each individual NE site of a micro-NEE serves as a support for an electrodeposited nanoparticle (NP) so that the surface distribution of NPs follows the random pattern of the supporting micro-NEE. Thus, we will also discuss the oxygen reduction and hydrogen evolution electrocatalytic reactions at Pt-modified micro-NEEs. C.G. Zoski, N. Yang, P.He, L. Berdondini, M.Koudelka-Hep, Anal. Chem., 2007, 79, 1474-1484. C.G. Zoski, M. Wijesinghe, Isr. J. Chem., 2010, 50, 347-359.

Electrochemistry at nanoelectrode ensembles of ultramicrodimensions

241st National Meeting (2011)

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