Extended Data Fig. 9: Characterizations of the 2D monolayer PCZ.
a, XRD profiles of LDH, LDH-S2O82− and LDH-PCZ. Similar to the ion-exchange and confined polymerization process of NAMC, the interlayer distance of LDH increases from 7.47 Å to 9.07 Å after the intercalation of S2O82−, and shrinks to 8.66 Å upon the decomposition of S2O82− to produce LDH-PCZ. b, TEM image and SAED pattern of PCZ. c, AFM image and the corresponding height profile of monolayer PCZ. d, Atomic resolution STEM-ADF image of monolayer PCZ. e, Overlay of the schematic atomic structural model on d. The 5-, 7- and 8-membered rings are highlighted with green, blue and purple, respectively. f, EELS spectrum acquired over a 32 nm × 32 nm sample area. The N content is approximately 4% as quantified from the EELS spectrum. g, STEM-ADF image of a PCZ nanosheet. h, Summed NBED pattern of the whole area in g over an area of 32 nm × 32 nm, showing diffuse halos characteristic of an amorphous structure. i, Array of the NBED patterns of the 16 × 16 subregions of g. The size of each subregion is 2 nm × 2 nm. j, k, two representative pairs of adjacent NBED patterns in i, all showing diffuse halos, suggesting that the sample features a highly disordered structure even at a scale as small as 2 nm × 2 nm.
