Electrooxidation of nitrite on a silica-cerium mixed oxide carbon paste electrode

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• 作者：Gustavo Silveira^a ; André ; ia de Morais^a ; Paulo Cé ; sar Mendes Villis^a ; Camila Marchetti Maroneze^b ; Yoshitaka Gushikem^b ; Alzira Maria Serpa Lucho^a ; Fá ; bio Luiz Pissetti^a ; ^{pissetti@unifal-mg.edu.br}
• 关键词：Sol&ndash ; gel process ; Mixed oxide ; Silica&ndash ; ceria ; Electrochemical sensor
• 刊名：Journal of Colloid and Interface Science
• 出版年：2012
• 出版时间：1 March 2012
• 年：2012
• 卷：369
• 期：1
• 页码：302-308
• 全文大小：701 K

文摘

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 m² g^?. Infrared spectroscopy of the SiCe material showed the formation of the SiOCe 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 ²⁹Si 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 ¡Á 10^? at 3.9 ¡Á 10^? mol L^?.