Perhaps the most surprising finding was that under high temperature reaction conditions, the rates for N2O etching increased over time, at least initially, whereas the sublimation rates slowed over time. The slowing of sublimation implies that the average stability of the sites exposed on the NP surfaces increased over time, thus we might expect that etching would also slow, as was observed for O2 etching 1 of graphitic NPs. The fact that the N2O etching rate increased as sublimation slowed, suggests that N2O etching can occur at sites that do not support O2 etching, and that become more common on the NP surface as mass is lost to etching and sublimation.