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Pyrolyzed polypyrrole-metal composites immobilized on glassy carbon for gas sensing and catalytic applications
|Justus Masa , Michael Bron , Wolfgang Schuhmann
Ruhr-Universität Bochum, Anal. Chem. - Elektroanalytik & Sensorik (ELAN), Universitätsstr. 150, Bochum 44780, Germany
The electrocatalytic application of novel electrode surfaces obtained by thermal treatment of polypyrrole-Co/Mn/Fe composites electrochemically synthesised on glassy carbon has been investigated using the oxygen reduction reaction. Carbon nanotubes (CNTs) were synthesized on glassy carbon by iron catalysed chemical deposition of acetylene vapour. The CNTs were then functionalized by treatment with nitric acid vapour. This was followed by sequentially controlled immobilization of polypyrrole, and dosing of metal (Mn, Co, Fe) particles, alternately, by electropolymerization and electrochemical reduction respectively. Electrochemical characterization by cyclic voltammetry and hydrodynamic linear sweep voltammetry shows that the immobilized polypyrrole-metal composites inherently catalyse the electroreduction of oxygen under acidic conditions. The activity of the composites is significantly augmented albeit with diminished stability, by pyrolysis at high temperatures (500oC-850oC) in a continuous flow of nitrogen. An insight into the nature of the active sites of both the unpyrolyzed and pyrolyzed composites is suggested based on transmission and scanning electron microscopic imaging (TEM and SEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) studies. This work presents a new approach for the synthesis of electrocatalytic surfaces with potential applications in fuel cells and gas sensors, for example biological and chemical oxygen sensors.
Presentation: Poster at SMCBS'2009 International Workshop, by Justus Masa
See On-line Journal of SMCBS'2009 International Workshop
Submitted: 2009-08-09 20:29 Revised: 2009-09-15 21:44