In this work, the modification of a glassy carbon
electrode with tetraruthenated porphyrins electrostatically
assembled onto a Nafion film, previously adsorbed on the
electrode surface, is reported. This modified electrode was
characterized by scanning electron microscopy–energydispersive
X-ray, Raman spectroscopy, UV-Vis spectroelectrochemistry,
and cyclic voltammetry. The Nafion film onto
the glassy carbon electrode shows a smooth disposition; when
the tetraruthenated porphyrin is incorporated on the Nafion
film, the complex is adsorbed in a homogeneous way. The
modified electrode catalyzes HSO3
− oxidation in water–
ethanol solutions and shows an enhanced stability compared
with the electrode modified with the dip coating method.
Rotating disk electrode experiments showed a kinetic
limitation to the electron transfer controlled by charge
propagation in the film. I/E curves show a Tafel slope of
120 mV/decade corresponding to a first electron-transfer
reaction, depending on the potential, as the determining step.
Spectroelectrochemical experiments demonstrated that Ru(II)
is the active site for the electrocatalysis.This work was supported by the program
“Anillo Bicentenario de Ciencia y Tecnología CONICYT” ACT No.
24. AECID and A/012666707 PCI projects. KC is grateful to
CONICYT for the doctoral scholarship
This work describes electrocatalytic detection of S(IV) compounds in water-ethanol solutions under acidic conditions,
on a glassy carbon electrode modified with Co(II) tetraruthenated porphyrin electrostatically assembled onto a
Nafion film. The Ipc current shows a linear relationship with the concentration of S(IV) oxo-anions. Controlled
potential electrolysis shows that thiosulfate was detected as reaction product. Rotating disk electrode and UV-visible
spectroelectrochemistry experiments showed a kinetic limitation to the electron transfer controlled by charge
propagation in the film and the formation of an intermediary between Co center and S(IV) species. The
reproducibility of the modification methodology presents a RSD of 4.1%.This work was supported by the program “Anillo Bicentenario
de Ciencia y Tecnolog a CONICYT”ACTN824. K. C.
and M. G. are grateful to CONICYT doctoral scholarships
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