Evaluating the performance of polypyrrole nanowires on the electrochemical sensing of ammonia in solution

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 669; pp. 90 - 94
• Main Authors: Massafera, Mariana P., Córdoba de Torresi, Susana I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2012
• Subjects: Ammonia; Amperometry; contact angle; electrochemistry; gold; Nanowires; oxidation; Polypyrrole; scanning electron microscopy; Sensors; Amperometry; Ammonia; Nanowires; Sensors; Polypyrrole
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2012.01.004

[Display omitted] ► Polypyrrole nanowires as electrochemical sensors for ammonia in solution. ► Electroactivity of these nanowires strictly depends on the electrodeposition method. ► Nanostructured sensors present different sensing behavior if compared to bulk ones. This work encompasses the direct electrodeposition of polypyrrole nanowires onto Au substrates using different electrochemical techniques: normal pulse voltammetry (NPV) and constant potential method with the aim in applying these films for the first time in ammonia sensing in solution. The performance of these nanowire-based sensors are compared and evaluated in terms of: film morphology (analyzed with scanning electron microscopy); their sensitivity towards ammonia; electrochemical and contact angle measurements. For nanowires prepared by NPV, the sensitivity towards ammonia increases with increasing amount of electrodeposited polypyrrole, as expected due to the role of polypyrrole as electrochemical transducer for ammonia oxidation. On the other hand, nanowires prepared potentiostatically displayed an unexpected opposite behavior, attributed to the lower conductivity of longer polypyrrole nanowires obtained through this technique. These results evidenced that the analytical and physico-chemical features of nanostructured sensors can differ greatly from those of their conventional bulky analogous.