Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/64595
Type: Artigo de periódico
Title: Electrooxidation of nitrite on a silica-cerium mixed oxide carbon paste electrode
Author: Silveira, G
de Morais, A
Villis, PCM
Maroneze, CM
Gushikem, Y
Lucho, AMS
Pissetti, FL
Abstract: A silica-cerium mixed oxide (SiCe) was prepared by the sol-gel process, using tetraethylorthosilicate and cerium nitrate as precursors and obtained as an amorphous solid possessing a specific surface area of 459 m(2) g(-1). Infrared spectroscopy of the SiCe material showed the formation of the Si-O-Ce linkage in the mixed oxide. Scanning electron microscopy/energy dispersive spectroscopy indicated that the cerium oxide particles were homogenously dispersed on the matrix surface. X-ray diffraction and Si-29 solid-state nuclear magnetic resonance implied non-crystalline silica matrices with chemical environments that are typical for silica-based mixed oxides. X-ray photoelectron spectroscopy showed that Ce was present in approximately equal amounts of both the 3+ and 4+ oxidation states. Cyclic voltammetry data of electrode prepared from the silica-cerium mixed oxide showed a peak for oxidation of Ce3+/Ce4+ at 0.76 V and electrochemical impedance spectroscopy equivalent circuit indicated a porous structure with low charge transfer resistance. In the presence of nitrite, the SiCe electrode shows an anodic oxidation peak at 0.76 V with a linear response as the concentration of the analyte increases from 3 x 10(-5) at 3.9 x 10(-3) mol L-1. (C) 2011 Elsevier Inc. All rights reserved.
Subject: Sol-gel process
Mixed oxide
Silica-ceria
Electrochemical sensor
Country: EUA
Editor: Academic Press Inc Elsevier Science
Rights: fechado
Identifier DOI: 10.1016/j.jcis.2011.11.060
Date Issue: 2012
Appears in Collections:Unicamp - Artigos e Outros Documentos

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