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In Situ Spectroelectrochemical Techniques Applied to Electrocatalysis

Shi, Ping
http://rave.ohiolink.edu/etdc/view?acc_num=case1144950929

Abstract Details

2006, Doctor of Philosophy, Case Western Reserve University, Chemistry.
A UV-visible rapid scan spectrophotometer was coupled to a Au rotating disk electrode for monitoring at near normal incidence the reflection-absorption spectrum of the diffusion boundary layer in [Fe(CN)6]4- aqueous solutions at several rotation rates over a potential region in which [Fe(CN)6]4- oxidizes generating highly absorbing [Fe(CN)6]3- (lmax = 420 nm). Results are in agreement with theoretical predictions quantitatively. Significant advantages offered by this unique type of spectroelectrochemical measurements were also discussed. The optical data collected with single wavelength, normal incidence UV-visible reflectance spectroscopy were used to determine differential coverage-potential relations of 3 kinds of cobalt phthalocyanines, CoTSPc, CoPc and CoTAPc, adsorbed on glassy carbon. No detectable changes in the DeltaR/R vs E profiles of either bare or macrocyclic-functionalized surfaces were observed upon addition of hydrazine to the neat 0.2 M NaOH solution at potentials at which these surfaces display electrocatalytic properties for its oxidation. Possible factors responsible for this behavior are discussed. A novel experimental arrangement that combines reflectance spectroscopy and microelectrodes was developed and the measurements were performed with Pt microelectrode in acid media. Linear correlations between reflectance signal (DeltaR/R) and surface oxide coverage were obtained after data analysis. By monitoring the changes in reflectance induced by oxidation of the substrate, this method allows for the rates of adsorbed CO oxidation on Pt(poly) microelectrodes to be determined. The results obtained revealed differences in the rates of the oxidation of COads induced by the potential at which the CO saturated layer is formed. In the last chapter, a method is described for simultaneous measurements of cyclic voltammetry and in situ dual spectroscopic techniques, normal incidence reflectance spectroscopy (RS) and probe beam deflection (PBD), at solid electrodes in aqueous electrolytes. The exquisite sensitivity of both of these optical methods to interfacial phenomena was illustrated using a monolayer of hemin irreversibly adsorbed on glassy carbon surfaces in 0.1 M Na2B4O7 (pH: ~9.2).
Daniel Scherson (Advisor)
122 p.
Spectroelectrochemistry; electrocatalysis; adsorption; reaction dynamics; microelectrode

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Citations

  • Shi, P. (2006). In Situ Spectroelectrochemical Techniques Applied to Electrocatalysis [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1144950929

    APA Style (7th edition)

  • Shi, Ping. In Situ Spectroelectrochemical Techniques Applied to Electrocatalysis. 2006. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1144950929.

    MLA Style (8th edition)

  • Shi, Ping. "In Situ Spectroelectrochemical Techniques Applied to Electrocatalysis." Doctoral dissertation, Case Western Reserve University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1144950929

    Chicago Manual of Style (17th edition)

case1144950929
859
© 2006, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.