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|Type:||Artigo de periódico|
|Title:||Copper (ii) Adsorbed On Sio2/sno2 Obtained By The Sol-gel Processing Method: Application As Electrochemical Sensor For Ascorbic Acid|
De Castro S.C.
|Abstract:||With the objective of producing a material showing better conductive properties to be used as a support for electroactive species, a SiO 2/SnO2 mixed oxide was prepared. The procedure for SiO2/SnO2 mixed oxide preparation using the sol-gel processing method, starting from tetraethylorthosilicate and SnI4 as precursor reagents, is described. SiO2/SnO2 with composition Sn=15.6 wt% and SBET=525 m2g-1, Vp=0.28 mlg-1, and Dp=1.5 nm, where S BET, Vp, and Dp are the specific surface area, the average pore volume, and the average pore diameter, respectively, was obtained. The X-ray photoelectron spectroscopy showed that the mixed oxide was thermally very stable for samples heat-treated at up to 1073 K. The Brønsted acid sites, probed with pyridine molecules for samples heat-treated at various temperatures, were chemically stable up to 473 K. Segregation of SnO2 crystalline phase was observed at 1473 K but no crystalline phase was verified for SiO2 at this temperature. The porous SiO2/SnO2 matrix was used as base for Cu(II) immobilization and an electrode was developed for application in electrochemical detection of vitamin C in tablets. © 2004 Elsevier Inc. All rights reserved.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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