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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

L-cysteine oxidation on Pt and Au rotating disk electrodes: Insights on mixed controlled kinetics

Full text
Author(s):
Dourado, Andre H. B. [1, 2] ; De Angelis, Leonardo D. [2] ; Arenz, Matthias [3] ; Cordoba de Torresi, I, Susana
Total Authors: 4
Affiliation:
[1] Tech Univ Munich, Phys Dept, James Franck Str 1, D-85748 Garching - Germany
[2] I, Univ Sao Paulo, Inst Quim, Av Prof Lineu Prestes, BR-05508080 Sao Paulo, SP - Brazil
[3] Univ Bern, Dept Chem & Biochem, Freiestr 3, CH-3012 Bern - Switzerland
Total Affiliations: 3
Document type: Journal article
Source: JOURNAL OF ELECTROANALYTICAL CHEMISTRY; v. 880, JAN 1 2021.
Web of Science Citations: 1
Abstract

L-Cysteine (L-Cys) oxidation on gold and platinum exhibits different behaviors due to adsorption phenomena related to the affinity between the S atom present on the L-Cys side chain and the metal sites. The adsorption of S on Au is very strong, which renders the determination of the L-Cys adsorption reaction order and its symmetry coefficient impossible. By contrast, on Pt electrodes, the L-Cys protonation state can be controlled by the electrolyte pH, and it is shown that the Tafel slope for L-Cys oxidation is pH dependent, with the most favorable kinetics being observed at pH = 9. Under this condition, the thiol is deprotonated, and thiolate is present, with L-Cys presenting a nucleophilic character. Differences between the two metals during L-Cys oxidation were also investigated. In rotating disk electrode measurements, the oxidation peak was observed to shift with the rotation rate, highlighting the kinetic activation control over this process and showing that diffusion influences this activation control as well. The combination of triangular potential perturbation and convection techniques allowed a chemometric soft model to be used to investigate reactions that are simultaneously controlled by activation and mass transport. (AU)

FAPESP's process: 13/25592-8 - Study of L-cysteine and L-cystine adsorption on platinum electrodes
Grantee:André Henrique Baraldi Dourado
Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
FAPESP's process: 18/13944-0 - SO2 electro-oxidation study. influence of the temperature and convection regime
Grantee:Leonardo Domenico De Angelis
Support Opportunities: Scholarships in Brazil - Scientific Initiation
FAPESP's process: 15/26308-7 - Optimization of the physicochemical properties of nano -structured materials for applications in molecular recognition, catalysis and energy conversion/storage
Grantee:Roberto Manuel Torresi
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 15/08300-9 - Study of L-cysteine and L-cystine adsorption and oxidation on Pt electrode by internal reflection infrared spectroscopy and DEMS
Grantee:André Henrique Baraldi Dourado
Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)