Nitrogen-doped graphene has sparked a lot of interest due to its exceptional catalytic activity in a variety of chemical processes. We examine the catalytic ability of a series of nitrogen-containing graphene surfaces for CO oxidation using first-principles computations. The activation of the O2 molecule in these systems is affected by the number and distribution of nitrogen impurities. According to the results, O2 may be readily decomposed to O* species adsorbed on the nearest carbon atoms in the most active nitrogen-doped structures. The oxidation of second CO is the rate-limiting step of the process due to the strong binding of the remaining O* moiety on the surface. Based on our findings, N-doped graphenes can provide excellent metal-free catalytic performance for CO oxidation.