Oxygen reduction on iron-melanin granular surfaces

We report the catalytic activity of iron-eumelanin granular deposits supported on graphite for the oxygen reduction in neutral and alkaline solutions. These deposits contain quinone groups and iron-melanin complexes as revealed by XPS, XANES, EXAFS, and IR spectroscopy. Voltammetric data show that t...

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Detalles Bibliográficos
Autores principales: Orive, A.G., Creus, A.H., Grumelli, D., Benitez, G.A., Andrini, L., Requejo, F.G., Bonazzola, C., Salvarezza, R.C.
Formato: JOUR
Materias:
Alkaline solutions
Catalytic activity
Dopaminergic neurons
Electrocatalytic activity
Eumelanins
EXAFS
Four electrons
Granular deposits
Hydroxyl species
IR spectroscopy
Lipid peroxidation
Neurodegeneration
Oxygen Reduction
Quinone groups
Voltammetric data
XANES
XPS
Catalyst activity
Deposits
Electrocatalysis
Electrochemical sensors
Electrolytic reduction
Graphite
Iron compounds
Neurons
Oxygen
Physical chemistry
Iron deposits
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_19327447_v113_n39_p17097_Orive
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:We report the catalytic activity of iron-eumelanin granular deposits supported on graphite for the oxygen reduction in neutral and alkaline solutions. These deposits contain quinone groups and iron-melanin complexes as revealed by XPS, XANES, EXAFS, and IR spectroscopy. Voltammetric data show that the iron-eumelanin system exhibits higher electrocatalytic activity than quinone/hydroquinone films (Q/QH) on the same substrate. In contrast to Q/QH deposits, the iron-containing eumelanin system is able to reduce oxygen with transfer of four electrons, thus allowing the formation of reactive hydroxyl species. Our results can explain the physical chemistry basis of the oxygen-radical induced lipid peroxidation and consequent neurodegeneration of the melanin-containing dopaminergic neurons observed by several authors. © 2009 American Chemical Society.

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