Details

Autor(en) / Beteiligte

• Lemes, Giovanni
• Sebastián, David
• Pastor, Elena
• Lázaro, María J.

Titel

N-doped graphene catalysts with high nitrogen concentration for the oxygen reduction reaction

Ist Teil von

• Journal of power sources, 2019-10, Vol.438, p.227036, Article 227036

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Nitrogen doped reduced graphene oxide (NrGO) catalysts and composites of these with carbon nitride (CN) with nitrogen content as high as 19.8 wt% and 35.8 wt%, respectively, have been synthesized by thermal annealing of multilayer graphene oxide and urea at different temperatures. Nitrogen has been effectively introduced as a mix of pyridinic, pyrrolic, pyridonic and quaternary bonding configurations into the carbon lattice of graphene upon removal of CN phase over 650 °C. The electrocatalytic activity towards oxygen reduction reaction (ORR) in 0.1 M NaOH has been investigated. NrGO catalysts with less nitrogen content show better performance than composites. NrGO produced at 800 °C presents the best activity with half-wave potential of 0.76 V vs. RHE and a mean number of electrons of 3.7, which are close to a commercial Pt/C catalyst. This study concludes that a high concentration of nitrogen atoms in multilayer reduced graphene oxide does not necessarily produce a highly active electrocatalyst, suggesting that carbon in the neighbourhood of nitrogen atoms are the active sites for ORR in alkaline medium. [Display omitted] •A simple N doping process of graphene is reported for high N concentration.•Annealing temperature determines N content and the presence of carbon nitride.•The oxygen reduction electro-activity improves with high annealing temperature.•Carbon bonded to nitrogen atoms are the active sites for oxygen reduction.