Fig. compares the etching of pre-heated silica NPs with analogous results for NPs of Si, SiC, and various carbon materials, all pre-heated above ~1900 K prior to oxidation. Fig. compares EEO2 vs. TNP for pre-heated silica, Si, C, and SiC NPs, based on mass loss rates taken from the first TNP ramps in experiments like that shown in To show the evolution of the NPs more clearly, Fig. compares experiments in which TNP was held constant for long etching periods as in Fig. . EEO2 is plotted vs. reaction time for three pre-heated silica NPs, for a typical Si NP, and for graphene platelet NP, 11 all of which had been pre-heated above 1750 K to clean the NPs prior to the etching study. For the Si NP, preheating would also have melted the NP (silicon Tmelt = 1687 K).