Quílez-Bermejo, Javier, Morallon, Emilia, Cazorla-Amorós, Diego
On the deactivation of N-doped carbon materials active sites during oxygen reduction reaction
Carbon. 2022, 189: 548-560. https://doi.org/10.1016/j.carbon.2021.12.086
URI: http://hdl.handle.net/10045/120731
DOI: 10.1016/j.carbon.2021.12.086
ISSN: 0008-6223 (Print)
Abstract: 
N-doped carbon materials have been considered one of the most promising options for the replacement of platinum-based electrocatalysts towards the oxygen reduction reaction (ORR). This work provides insights into the deactivation routes of N-doped carbon materials. The changes occurring in the active sites of N-doped carbon catalysts have been analyzed in detail through pre- and post-ORR characterization by XPS of selectively N-doped carbon materials. Moreover, computational modelling was used to deepen into the deactivation mechanism of N-doped carbon materials in the ORR. From XPS and computational modelling, it can be concluded that the deactivation of graphitic-type nitrogen species, during the ORR in both acidic and alkaline environments, occurs through oxidation and tautomerization reactions that result in the formation of N–C–O-type groups. In acidic environment, the reaction kinetics is slower due to the high stability of the ORR intermediates. In alkaline electrolyte, the N–C–O-type groups can be easily formed due to the interaction of graphitic-type N species and the OH− anions from the electrolyte. In this case, the catalytic activity is due to the contribution of both graphitic nitrogen groups and N–C–O species.
Keywords:Carbon materials, Nitrogen, Electrocatalysts, Oxygen reduction reaction
Elsevier
info:eu-repo/semantics/article