On the deactivation of N-doped carbon materials active sites during oxygen reduction reaction. (15th April 2022)

• Record Type: Journal Article
• Authors: Quílez-Bermejo, Javier; Morallón, Emilia; Cazorla-Amorós, Diego
• Is Part Of: Carbon. Volume 189(2022)
• Page Start: 548
• Page End: 560
• Publication Date: 2022-04-15
• Subjects: Carbon materials -- Nitrogen -- Electrocatalysts -- Oxygen reduction reaction; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2021.12.086
• Languages: English
• ISSNs: 0008-6223

Abstract

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. Graphical abstract: Image 1