Using first principles density functional theory calculations, we systematically studied oxygen reduction reactions (ORRs) on N-doped graphene (N-Gr) with and without a Cu metallic support (N-Gr/Cu(111) surface). Our ab-initio calculated free energy diagrams surprisingly show that oxygen molecules are dissociated into two oxygen atoms on the N-Gr/Cu(111) surface, which alters the well-known associative ORR mechanisms on pure graphene and N-Gr. Our results, however, indicate that the mechanistic shift does not directly lead to enhancement of ORR activity once water molecules solvate the N-Gr/Cu(111) surface via substantially stabilized intermediates such as O, OH, and OOH. Our results suggest that transition metal supports can be a promising way to control the ORR mechanism on doped graphene and that the evaluation of ORR activity requires understandings of not only the electronic structures of doped graphene but also the chemical interactions between the intermediates and solvating water molecules.
Bibliographical noteFunding Information:
This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (MEST) (2012K1A4A3053565), and by the New and Renewable Energy R&D Program (20113020030020) under the Ministry of Knowledge Economy, Republic of Korea. This work was supported by the Global Frontier R&D Program (2013-073298) on Center for Hybrid Interface Materials (HIM), funded by the Ministry of Science, ICT & Future Planning. Korea Institute of Science and Technology Information (KISTI) to allow us to use the supercomputing facility (KSC-2013-C2-008).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)