where λ ≡1/ Nring is the mean probability that a hexagonal ring has one defect (SW or vacancy). When considering NPC (θ-Al2O3) as an example, the single, double, and triple defect formation probabilities, P1, P2 and P3, are calculated to be 1.9 × 10 -2 , 1.9 × 10 -4 , and 1.2 × 10 -6 , respectively, as shown in Fig. , using the value of λ obtained from the Raman spectrum (λRaman = 2.0×10 -2 ), which semi-quantitively agrees with that from TPD analysis (λTPD= 4.2×10 -2 ) as shown in Table . λTPD is proportional to λRaman 1/2 (Fig. ). The values of λTPD, λRaman (Table ), and Pn (Fig. ) indicate that the density of defects in NPCs are two orders of magnitude lower than that in ZTC, a nanoporous carbon material with a well-defined structure (see ESI for details). NPGs obtained by annealing of NPCs at a temperature of 1800℃ retain the single-layer graphene structure, as confirmed by the TEM images (Fig. ) and nanoporosity (Table ). The measured Raman spectra and deconvoluted peaks of NPGs are shown in Figs. and. There also exist eight pronounced peaks in the spectra, including the D band at 1330-1340 cm -1 , while the small Ntotal of NPG by TPD analysis (0.16-0.39 mmol g -1 , Table ) suggests very few edge defects. The nitrogen sorption isotherms of NPGs (Fig. ) are classified as type IV with a distinct hysteresis loop, and the SBET values derived from the NPC (θ-Al2O3) 5.33 2.12 0.43 2.3×10 9.2 1.05 3.1 4.2×10 5.12 1.68 1.39 1.9×10 3 9.0 ---0.16 2.6×10 -3 1.1×10 ---15.4 1.5×10 -1 1.1×10 0 a amount of evolved gases determined by TPD analysis (Fig. ); b defined as the number of defects per hexagon based on SBET, Ntotal, and the area of the graphene's hexagon Sh = 0.0523 nm . λTPD values estimate the defects at the edges of NPGs; c derived from the deconvolution of the original Raman spectra shown in Fig. ; d determined by the thermogravimetric analysis of the carbon/alumina composites as shown in Fig. ; e the Raman spectra are shown in Fig. .