Transition Metal Atoms Embedded in Graphene: How Nitrogen Doping Increases CO Oxidation Activity

We study 14 transition metals on pristine and N-doped graphene using density functional theory. For double vacancies, nitrogen doping increases the binding strength of harder transition metals to the support and reduces their oxygen affinity. Inversely, the oxygen affinity of softer metals increases. Since O-2, binding energies are correlated with the CO oxidation barrier in a volcano-like trend, doping also affects the activity of the single-atom catalyst. Among these systems, Fe atoms embedded in N-doped graphene are the most active CO oxidation catalysts. These insights can be used to guide the synthesis of highly active oxidation catalysts from nonprecious metals.