resumo
Ultrathin multilayer films containing metal-substituted polyoxometalates, [PW(1) (t)Fe(III)(H(2)O)O(39)](4-) (PW(11)Fe) or [siW(11)Fe(III)(H(2)O)O(39)](5-) (SiW(11)Fe), and poly(ethylenimine) (PEI) were prepared by the electrostatic layer-by-layer self-assembly method on a glassy carbon electrode. The multilayer films were characterized by cyclic voltammetty and scanning electron microscopy and UV-Vis absorption spectroscopy on a quartz slide was used to monitor film growth Cyclic voltammetry indicates that the electrochemical properties of the polyoxometalates are completely maintained in the multilayer films, and the influence of scan rate on the voltammetric features showed that the first tungsten reduction process for immobilized PW(11)Fe and SAW, IFe is a surface-confined process Studies with [Fe(CN(6))](3-/4-) as electrochemical probe showed that their permeability depends on the thickness of the multilayer films, if the outermost layer is negatively charged. Additionally, the (PEI/SiW(11)Fe)(n) multilayer films showed electrocatalytic properties towards nitrite reduction. (C) 2010 Elsevier B.V. All rights reserved
palavras-chave
GLASSY-CARBON ELECTRODE; LAYERED POLYELECTROLYTE FILMS; TRANSITION-METAL; ELECTROCATALYTIC REDUCTION; HOMOGENEOUS CATALYSIS; ULTRATHIN FILMS; POLYOXOMETALATE; POLYMER; NITRITE; HETEROPOLYTUNGSTATES
categoria
Materials Science; Physics
autores
Fernandes, DM; Carapuca, HM; Brett, CMA; Cavaleiro, AMV
nossos autores
Ana Maria Vieira Silva Viana Cavaleiro
Professor CatedráticoGrupos
agradecimentos
The authors thank Fundacao para a Ciencia e a Tecnologia (FCT) for financial support (project POCI 2010-Feder-POCI/QUI/56534/2004). Diana M. Fernandes acknowledges FCT for her PhD grant SFRH/BD/30797/2006. Thanks are also due to CICECO and the University of Aveiro