Theoretical insights on the reaction pathways of the oxygen reduction reaction on yttrium doped graphene as a catalyst in fuel cells

- Y-N4 doped graphene is stable thermodynamically.
- ORR is a four-electron process.
- The most favorable pathway is the OOH hydrogenation to form OH + OH with energy barrier of 1.09 eV.

The pyrolyzed transition metal and nitrogen-derived carbon are recently proposed as promising candidates in substituting Pt catalyst for oxygen reduction reaction (ORR) in the fuel cells. In this study, the active sites and reaction pathways for ORR on Y-N4 doped graphene are investigated theoretically. The ORR elementary reactions could take place within a small region around the Y-N4 moiety and its adjacent eight carbon atoms. ORR is a four electron process. The kinetically most favorable pathway is the OOH hydrogenation into OH + OH species, in which the formation of the second H2O is the rate-determining step with an energy barrier of 1.09 eV. The free energy change is discussed on different electrode potentials.