The experiments above show that all types of carbon NPs evolve under oxidizing conditions, such that EEO2 decreases by 2 to 4 orders of magnitude. In contrast, when graphite and graphene NP were heated (to 2100 K) in argon to drive sublimation, the decreases in sublimation rates were much smaller. For example, the average decrease was a factor of 6 at 1800 K and just a factor of 1.6 at 2100 K. Even when an NP was allowed to sublime for >10 hours at 1900 K, losing 12% of its initial mass, Rsublimation only slowed by a factor of ~2. These small decreases can be rationalized in terms of modest decreases in the number of under-coordinated surface sites due to the combined effects of annealing and preferential sublimation from the least stable surface sites.