Photoelectrochemical reduction of nitrate ions on porous silicon and different silicon modified electrodes

• E. C MUÑOZ ^[1] ; C. A HEYSER ^[1] ; R. S SCHREBLER ^[1] ; R. G HENRÍQUEZ ^[1] ; R. E MAROTTI ^[2]
  1. [1] Pontificia Universidad Católica de Valparaíso

     Pontificia Universidad Católica de Valparaíso

     Valparaíso, Chile

     
  2. [2] Universidad de la República

     Universidad de la República

     Uruguay

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 56, Nº. 3, 2011, págs. 781-785
• Idioma: inglés
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• Resumen

  • We examined the reduction reaction of nitrate ions on different electrode systems: silicon monocrystalline («-type and p-type), porous silicon, and silicon modified by electrodeposited metallic rhenium. In a first stage, voltammetric analysis in different HF media was performed. With this technique it was possible to establish the different processes associated to porous silicon formation. The morphology of the porous silicon was studied using AFM. Voltammetric analysis was then performed using different silicon substrates. This was then used to study the electrochemical reduction reaction of nitrate ions. A decrease in the overpotential of the reaction was observed, with a consequent increase in current density when the silicon electrodes were modified by electrodeposited rhenium. Finally, an analysis of the reaction products from the nitrate electroreduction was carried out using photoelectrolysis at controlled potential.