Predoped Oxygenated Defects Activate Nitrogen-Doped Graphene for the Oxygen Reduction Reaction

Lin Jiang; Bas van Dijk; Longfei Wu; Clément Maheu; Jan P Hofmann; Viorica Tudor; Marc T M Koper; Dennis G H Hetterscheid; Grégory F Schneider

doi:10.1021/acscatal.1c03662

Predoped Oxygenated Defects Activate Nitrogen-Doped Graphene for the Oxygen Reduction Reaction

ACS Catal. 2022 Jan 7;12(1):173-182. doi: 10.1021/acscatal.1c03662. Epub 2021 Dec 14.

Authors

Lin Jiang¹, Bas van Dijk¹, Longfei Wu², Clément Maheu³, Jan P Hofmann^{2

3}, Viorica Tudor¹, Marc T M Koper¹, Dennis G H Hetterscheid¹, Grégory F Schneider¹

Affiliations

¹ Leiden Institute of Chemistry, Leiden University, 2333CC Leiden, The Netherlands.
² Laboratory for Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
³ Surface Science Laboratory, Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287 Darmstadt, Germany.

Abstract

The presence of defects and chemical dopants in metal-free carbon materials plays an important role in the electrocatalysis of the oxygen reduction reaction (ORR). The precise control and design of defects and dopants in carbon electrodes will allow the fundamental understanding of activity-structure correlations for tailoring catalytic performance of carbon-based, most particularly graphene-based, electrode materials. Herein, we adopted monolayer graphene - a model carbon-based electrode - for systematical introduction of nitrogen and oxygen dopants, together with vacancy defects, and studied their roles in catalyzing ORR. Compared to pristine graphene, nitrogen doping exhibited a limited effect on ORR activity. In contrast, nitrogen doping in graphene predoped with vacancy defects or oxygen enhanced the activities at 0.4 V vs the reversible hydrogen electrode (RHE) by 1.2 and 2.0 times, respectively. The optimal activity was achieved for nitrogen doping in graphene functionalized with oxygenated defects, 12.8 times more than nitrogen-doped and 7.7 times more than pristine graphene. More importantly, oxygenated defects are highly related to the 4e^- pathway instead of nitrogen dopants. This work indicates a non-negligible contribution of oxygen and especially oxygenated vacancy defects for the catalytic activity of nitrogen-doped graphene.