| Autor: |
Ivar Kruusenberg, Urmas Joost, Eugene Shulga, Merilin Vikkisk, Ilmar Kink, Kaido Tammeveski |
| Rok vydání: |
2014 |
| Předmět: |
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| Zdroj: |
Applied Catalysis B: Environmental. 147:369-376 |
| ISSN: |
0926-3373 |
| DOI: |
10.1016/j.apcatb.2013.09.011 |
| Popis: |
a b s t r a c t Nitrogen-doped graphene nanosheets were prepared from nitrogen precursor and graphene oxide (GO), which was synthesised from graphite by modified Hummers' method. Melamine, urea and dicyandi- amide (DCDA) were used as nitrogen precursors and the doping was achieved by pyrolysing GO in the presence of these nitrogen-containing compounds at 800 ◦C. The N-doped graphene (NG) samples were characterised by scanning electron microscopy and X-ray photoelectron spectroscopy, the latter method revealed successful nitrogen doping. The oxygen reduction reaction (ORR) was examined on NG-modified glassy carbon (GC) electrodes in alkaline media using the rotating disk electrode (RDE) method. It was found on the basis of the RDE results that nitrogen-containing catalysts possess higher electrocatalytic activity towards the ORR than the annealed GO. Oxygen reduction on this GO material and on NG catalysts prepared by pyrolysis of GO-melamine and GO-urea followed a two-electron pathway at low overpo- tentials, but at higher cathodic potentials the desirable four-electron pathway occurred. For NG catalyst prepared from GO-DCDA a four-electron O2 reduction pathway dominated in a wide range of potentials. The half-wave potential of O2 reduction on this NG catalyst was close to that of Pt/C catalyst in 0.1 M KOH. These results are important for the development of alkaline membrane fuel cells based on non-platinum cathode catalysts. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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