Electrocatalytic Reduction of HNO2 by a Silicomolybdate Polyanion: A Differential Electrochemical Mass Spectrometry Study

✍ Scribed by Catherine Debiemme-Chouvy; Hubert Cachet; Guy Folcher; Claude Deslouis

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 154 KB
• Volume: 19
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200603719

✦ Synopsis

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 Keggintype HPA, SiMo 12 O 4À 40 , 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 4À 40 and HSO À 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 4À 40 . Under an applied cathodic potential, when both HNO 2 and SiMo 12 O 4À 40 are present in the medium, NO gas is produced whereas, when SiMo 12 O 4À 40 ions are immobilized in a PPy film, N 2 O evolves and the NO concentration, notably due to the disproportionation of HNO 2 , decreases.