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Electrocatalytic Reduction of HNO 2 by a Silicomolybdate Polyanion: A Differential Electrochemical Mass Spectrometry Study
Author(s) -
DebiemmeChouvy Catherine,
Cachet Hubert,
Folcher Guy,
Deslouis Claude
Publication year - 2007
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200603719
Subject(s) - polypyrrole , chemistry , electrochemistry , inorganic chemistry , hydrogen peroxide , disproportionation , mass spectrometry , nitrous acid , electrocatalyst , amperometry , electrode , catalysis , chromatography , organic chemistry
Electrocatalytic activities towards the reduction of important analytes such as nitrite, bromate, chlorate and hydrogen peroxide have been demonstrated for numerous heteropolyanions (HPAs). In this paper, the behavior of a Keggin‐type HPA, SiMo 12 O $\rm{ {_{40}^{4-}}}$ , on the one hand in solution and on the other hand immobilized in a conducting polymer, polypyrrole (PPy), in the presence of nitrous acid (HNO 2 ) is examined. It is shown that the PPy films codoped with SiMo 12 O $\rm{ {_{40}^{4-}}}$ and HSO $\rm{ {_{4}^{-}}}$ ions could be used as sensitive part of an amperometric sensor even if the response is limited by HNO 2 diffusion into the PPy film. Differential electrochemical mass spectrometry (DEMS) was used to determine the gas formed during nitrous acid reduction by H 2 SiMo 12 O $\rm{ {_{40}^{4-}}}$ . Under an applied cathodic potential, when both HNO 2 and SiMo 12 O $\rm{ {_{40}^{4-}}}$ are present in the medium, NO gas is produced whereas, when SiMo 12 O $\rm{ {_{40}^{4-}}}$ ions are immobilized in a PPy film, N 2 O evolves and the NO concentration, notably due to the disproportionation of HNO 2 , decreases.