The reactivity of platinum microelectrodes. Issue 41 (7th October 2016)

• Record Type: Journal Article
• Authors: Jacobse, Leon; Raaijman, Stefan J.; Koper, Marc T. M.
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 41(2016)
• Page Start: 28451
• Page End: 28457
• Publication Date: 2016-10-07
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c6cp05361k
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Platinum ultramicroelectrodes exhibit lower reactivity towards surface sensitive reactions than macroelectrodes, typically due to (trace) contamination, making electrochemical characterization very important for a proper comparison. Abstract : Despite the widespread application of ultramicroelectrodes (UMEs), the customary method of their electrochemical characterization via outer sphere redox probing has serious limitations. In this study we provide additional insights into this subject by measuring not only outer sphere redox couples, but also blank voltammetries and the reactivity towards various catalytic reactions of Pt UMEs. The data for the UMEs are compared to those for macroscale Pt electrodes that can be flame-annealed. Although the reactivity is similar for reactions that are rather insensitive to the surface structure (and/or composition), UMEs perform much worse for more surface sensitive catalytic reactions. This effect can be explained by the UMEs being contaminated much faster, though it remains to be established if the origin of this contamination lies in the preparation method or in the impurities in the (high-purity grade) chemicals used. Our study recommends that catalytic reactivity measurements on ultramicroelectrodes should always be accompanied by blank voltammetries and the results have to be interpreted extremely carefully.