Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6471210 | Electrochimica Acta | 2017 | 12 Pages |
â¢Graphene modified with cystamine and DWCNT forms a superior Pt catalyst support.â¢CO electro-oxidation onset potential is lowered by the cystamine modification.â¢Ethanol electro-oxidation activity, stability and poisoning resistance increases.â¢Activation energy for ethanol oxidation is higher with cystamine modification.
In this study, Pt nanoparticles are deposited on the surface of nitrogen-sulfur functionalized reduced graphene oxide and mixed with double wall carbon nanotubes (Pt/NS-rGO/DWCNT). The obtained nanocomposite is used as an electrocatalyst for the ethanol electro-oxidation reaction (EOR). CO oxidation studies with differential electrochemical mass spectroscopy (DEMS) show a lower onset potential indicating higher poisoning tolerance of these materials. The electrocatalytic activity of the Pt/NS-rGO/DWCNT nanocomposite is studied at different temperatures (40, 50, 60, and 70 °C) and compared with that of Pt/rGO, Pt/rGO/DWCNT composites and commercial carbon-supported Pt catalyst. Pt/rGO/DWCNT and Pt/NS-rGO/DWCNT display significantly higher ethanol electro-oxidation currents especially at low potentials relevant to fuel cell applications. At high temperatures (>50 °C), Pt/NS-rGO/DWCNT is the most active catalyst in concordance with its higher apparent activation energy. Pt/NS-rGO/DWCNT is also the most durable of the catalysts after a 500 potential cycle test and suffers the least from poisoning effects during chronopotentiometric testing. These results allow to conclude that combining NS-functionalized graphene catalyst support with DWCNT to form a composite provides excellent performances due to enhanced Pt electrocatalytic activity from NS-functionalization and enhanced mass transfer from the DWCNT filler.
Graphical abstractDownload high-res image (99KB)Download full-size image