Influence of size and oxidative treatments of multi-walled carbon nanotubes on their electrocatalytic properties
| Autor: | Alejandro Álvarez-Lueje, Soledad Bollo, M. I. Martínez, A. Ansón, Paulina Cañete-Rosales, M. J. Martínez González, Valeria Ortega |
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| Přispěvatelé: | Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Consejo Superior de Investigaciones Científicas (España), Comisión Nacional de Investigación Científica y Tecnológica (Chile) |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Thermogravimetric analysis
Materials science General Chemical Engineering Inorganic chemistry education Carbon nanotube Electrocatalyst Redox Pseudocapacitance law.invention chemistry.chemical_compound chemistry law Electrochemistry Fourier transform infrared spectroscopy Cyclic voltammetry Hydrogen peroxide |
| Zdroj: | ELECTROCHIMICA ACTA Artículos CONICYT CONICYT Chile instacron:CONICYT Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | The influence of chemical oxidation on the electrochemical behavior against hydrogen peroxide of long and short multi-walled carbon nanotubes (MWCNT) has been investigated. Different degrees of oxidation with a sulfo-nitric mixture and with nitric acid were used and a complete physical and oxygen functional group characterization was performed by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), acid group titration, transmission and scanning electron microscopies (TEM/SEM), elemental analysis, thermogravimetric analysis (TGA), nitrogen adsorption isotherms and cyclic voltammetry. The results revealed that electrodes modified using pristine short CNT (s-NC) present higher amperometric response against hydrogen peroxide than that obtained using long CNT (l-NC), which correlates with the greater degree of packing observed for l-NC by SEM and the long and thin structures observed in s-NC. On the other hand, the chemical oxidation process increases slightly the sensitivity of resulting electrodes, in about 25%, for both s-NC and l-NC indicating that for hydrogen peroxide oxidation the metal catalyst impurities, that are removed in the oxidation process, are not as relevant in the electrocatalysis as the increase in the capacitance values observed in the oxidized CNTs. The presence of oxygen groups introduces (a) new sites for redox reaction (pseudocapacitance) and (b) strong polar sites that would adsorb water molecules favoring double-layer formation (double-layer capacitance). Financial support from the Fondecyt-CHILE (Grant 1080526), CSIC 200480E481 Intramural Project and CSIC/CONICYT 2009CL0057 project (2010–2011) are gratefully acknowledged. P.C. acknowledges CONICYT scholarships for PhD studies in Chile, PhD scholarship support and PhD fellowship stay abroad (BECAS-CHILE). |
| Databáze: | OpenAIRE |
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